From d117ca7a2a4dfda62e46f448a219828db3c7b1a5 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 10 Oct 2019 10:37:29 +0200
Subject: [PATCH 01/30] simple extension example

---
 examples/simple/README.md                     |  34 ++++++++++++
 .../server_simple.json                        |   7 +++
 .../simple/jupyter_server_simple/__init__.py  |   8 +++
 .../jupyter_server_simple/application.py      |  52 ++++++++++++++++++
 .../simple/jupyter_server_simple/handler.py   |  11 ++++
 .../jupyter_server_simple/handler_template.py |  11 ++++
 .../jupyter_server_simple/static/favicon.ico  | Bin 0 -> 32038 bytes
 .../jupyter_server_simple/static/test.html    |   1 +
 .../jupyter_server_simple/templates/404.html  |   5 ++
 .../templates/browser-open.html               |  18 ++++++
 .../templates/error.html                      |  21 +++++++
 .../jupyter_server_simple/templates/main.html |   5 ++
 .../jupyter_server_simple/templates/page.html |  20 +++++++
 .../templates/server_simple.html              |   5 ++
 examples/simple/setup.py                      |  38 +++++++++++++
 15 files changed, 236 insertions(+)
 create mode 100644 examples/simple/README.md
 create mode 100644 examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json
 create mode 100644 examples/simple/jupyter_server_simple/__init__.py
 create mode 100644 examples/simple/jupyter_server_simple/application.py
 create mode 100644 examples/simple/jupyter_server_simple/handler.py
 create mode 100644 examples/simple/jupyter_server_simple/handler_template.py
 create mode 100644 examples/simple/jupyter_server_simple/static/favicon.ico
 create mode 100644 examples/simple/jupyter_server_simple/static/test.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/404.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/browser-open.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/error.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/main.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/page.html
 create mode 100644 examples/simple/jupyter_server_simple/templates/server_simple.html
 create mode 100755 examples/simple/setup.py

diff --git a/examples/simple/README.md b/examples/simple/README.md
new file mode 100644
index 0000000000..c6259a12b9
--- /dev/null
+++ b/examples/simple/README.md
@@ -0,0 +1,34 @@
+# Jupyter Server Simple Extension Example
+
+This folder contains an example to develop an simple extension on top of Jupyter Server.
+
+```bash
+# Install the server simple extension.
+python setup.py develop
+```
+
+```bash
+# Start the jupyter server simple extension.
+jupyter server-simple
+```
+
+Render server content in your browser.
+
+```bash
+# Default server page.
+open http://localhost:8888
+# Default favicon.
+open http://localhost:8888/favicon.ico
+# HTML static page.
+open http://localhost:8888/static/server_simple/test.html
+# Content from Handlers.
+open http://localhost:8888/server_simple
+open http://localhost:8888/server_simple/something?var1=foo
+# Content from Template.
+open http://localhost:8888/template
+```
+
+## TO FIX
+
++ The token created in `browser-open.html` is `None` - http://localhost:8888/?token=None
++ This static favicon request fails with `403 : Forbidden - favicon.ico is not in root static directory` - http://localhost:8888/static/server_simple/favicon.ico
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json b/examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json
new file mode 100644
index 0000000000..607ec527aa
--- /dev/null
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json
@@ -0,0 +1,7 @@
+{
+    "ServerApp": {
+        "jpserver_extensions": {
+            "server_simple": true
+        }
+    }
+}
diff --git a/examples/simple/jupyter_server_simple/__init__.py b/examples/simple/jupyter_server_simple/__init__.py
new file mode 100644
index 0000000000..21752c111f
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/__init__.py
@@ -0,0 +1,8 @@
+from .application import ServerSimple
+
+EXTENSION_NAME = "server_simple"
+
+def _jupyter_server_extension_paths():
+    return [{"module": EXTENSION_NAME}]
+
+load_jupyter_server_extension = ServerSimple.load_jupyter_server_extension
diff --git a/examples/simple/jupyter_server_simple/application.py b/examples/simple/jupyter_server_simple/application.py
new file mode 100644
index 0000000000..430baa8167
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/application.py
@@ -0,0 +1,52 @@
+import os, jinja2
+from .handler import ServerSimpleHandler
+from .handler_template import ServerSimpleTemplateHandler
+from jupyter_server.extension.application import ExtensionApp
+
+DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
+DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
+
+class ServerSimple(ExtensionApp):
+    
+    # Name of the extension
+    extension_name = "server_simple"
+
+    # Local path to static files directory.
+    static_paths = [
+        DEFAULT_STATIC_FILES_PATH
+    ]
+
+    # Local path to templates directory.
+    template_paths = [
+        DEFAULT_TEMPLATE_FILES_PATH
+    ]
+
+    def initialize_handlers(self):
+        self.handlers.append(
+            (r'/server_simple', ServerSimpleHandler, {})
+        )
+        self.handlers.append(
+            (r'/server_simple/(.+)$', ServerSimpleHandler, {})
+        )
+        self.handlers.append(
+            (r'/template', ServerSimpleTemplateHandler, {})
+        )
+
+    def initialize_templates(self):
+        jenv_opt = {"autoescape": True}
+        env = jinja2.Environment(
+            loader=jinja2.FileSystemLoader(self.template_paths),
+            extensions=["jinja2.ext.i18n"],
+            **jenv_opt
+        )
+        template_settings = {"server_simple_jinja2_env": env}
+        self.settings.update(**template_settings)
+
+    def initialize_settings(self):
+        pass
+
+#-----------------------------------------------------------------------------
+# Main entry point
+#-----------------------------------------------------------------------------
+
+main = launch_new_instance = ServerSimple.launch_instance
diff --git a/examples/simple/jupyter_server_simple/handler.py b/examples/simple/jupyter_server_simple/handler.py
new file mode 100644
index 0000000000..d8de78605f
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/handler.py
@@ -0,0 +1,11 @@
+from jupyter_server.extension.handler import ExtensionHandler
+
+class ServerSimpleHandler(ExtensionHandler):
+    
+    def get(self, matched_part=None, *args, **kwargs):
+        var1 = self.get_argument('var1', default=None)
+        components = [x for x in self.request.path.split("/") if x]
+        self.write('<h1>Hello Server Simple from Handler.</h1>')
+        self.write('<p>matched_part: {}</p>'.format(matched_part))
+        self.write('<p>var1: {}</p>'.format(var1))
+        self.write('<p>components: {}</p>'.format(components))
diff --git a/examples/simple/jupyter_server_simple/handler_template.py b/examples/simple/jupyter_server_simple/handler_template.py
new file mode 100644
index 0000000000..9966ea22a5
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/handler_template.py
@@ -0,0 +1,11 @@
+from jupyter_server.extension.handler import ExtensionHandler
+
+class ServerSimpleTemplateHandler(ExtensionHandler):
+    
+    def get_template(self, name):
+        """Return the jinja template object for a given name"""
+        return self.settings['server_simple_jinja2_env'].get_template(name)
+
+    def get(self):
+#        print(self.get_template('server_simple.html'))
+        self.write(self.render_template('server_simple.html'))
diff --git a/examples/simple/jupyter_server_simple/static/favicon.ico b/examples/simple/jupyter_server_simple/static/favicon.ico
new file mode 100644
index 0000000000000000000000000000000000000000..2d1bcff7ca0ed6c77fdf1b016986f9137a43d31a
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diff --git a/examples/simple/jupyter_server_simple/static/test.html b/examples/simple/jupyter_server_simple/static/test.html
new file mode 100644
index 0000000000..0d8106c290
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/static/test.html
@@ -0,0 +1 @@
+<h1>Hello Server Simple from test HTML page.</h1>
diff --git a/examples/simple/jupyter_server_simple/templates/404.html b/examples/simple/jupyter_server_simple/templates/404.html
new file mode 100644
index 0000000000..e29646af1a
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/404.html
@@ -0,0 +1,5 @@
+{% extends "error.html" %}
+{% block error_detail %}
+<p>{% trans %}You are requesting a page that does not exist!{% endtrans %}</p>
+{% endblock %}
+
diff --git a/examples/simple/jupyter_server_simple/templates/browser-open.html b/examples/simple/jupyter_server_simple/templates/browser-open.html
new file mode 100644
index 0000000000..6f277967fc
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/browser-open.html
@@ -0,0 +1,18 @@
+{# This template is not served, but written as a file to open in the browser,
+   passing the token without putting it in a command-line argument. #}
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta http-equiv="refresh" content="1;url={{ open_url }}" />
+    <title>Opening Jupyter Notebook</title>
+</head>
+<body>
+
+<p>
+    This page should redirect you to Jupyter Notebook. If it doesn't,
+    <a href="{{ open_url }}">click here to go to Jupyter</a>.
+</p>
+
+</body>
+</html>
diff --git a/examples/simple/jupyter_server_simple/templates/error.html b/examples/simple/jupyter_server_simple/templates/error.html
new file mode 100644
index 0000000000..1e3fae6225
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/error.html
@@ -0,0 +1,21 @@
+{% extends "page.html" %}
+
+{% block site %}
+
+<div class="error">
+    {% block h1_error %}
+    <h1>{{status_code}} : {{status_message}}</h1>
+    {% endblock h1_error %}
+
+    {% block error_detail %}
+    {% if message %}
+    <p>{% trans %}The error was:{% endtrans %}</p>
+    <div class="traceback-wrapper">
+    <pre class="traceback">{{message}}</pre>
+    </div>
+    {% endif %}
+    {% endblock error_detail %}
+</div>
+
+{% endblock %}
+
diff --git a/examples/simple/jupyter_server_simple/templates/main.html b/examples/simple/jupyter_server_simple/templates/main.html
new file mode 100644
index 0000000000..51f8be1c07
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/main.html
@@ -0,0 +1,5 @@
+{% extends "page.html" %}
+
+{% block site %}
+<h1>Server 1 is running.</h1>
+{% endblock site %}
diff --git a/examples/simple/jupyter_server_simple/templates/page.html b/examples/simple/jupyter_server_simple/templates/page.html
new file mode 100644
index 0000000000..cf01c9a0b0
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/page.html
@@ -0,0 +1,20 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>{% block title %}Jupyter Server 1{% endblock %}</title>
+    {% block favicon %}<link id="favicon" rel="shortcut icon" type="image/x-icon" href="{{ static_url("favicon.ico") }}">{% endblock %}
+    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    {% block meta %}
+    {% endblock %}
+</head>
+<body>
+  <div id="site">
+    {% block site %}
+    {% endblock site %}
+  </div>
+  {% block after_site %}
+  {% endblock after_site %}
+</body>
+</html>
diff --git a/examples/simple/jupyter_server_simple/templates/server_simple.html b/examples/simple/jupyter_server_simple/templates/server_simple.html
new file mode 100644
index 0000000000..36190d42c6
--- /dev/null
+++ b/examples/simple/jupyter_server_simple/templates/server_simple.html
@@ -0,0 +1,5 @@
+{% extends "page.html" %}
+
+{% block site %}
+<h1>Hello Server Simple from Template.</h1>
+{% endblock site %}
diff --git a/examples/simple/setup.py b/examples/simple/setup.py
new file mode 100755
index 0000000000..9ef276ee28
--- /dev/null
+++ b/examples/simple/setup.py
@@ -0,0 +1,38 @@
+import setuptools
+
+VERSION = '0.0.1'
+
+setuptools.setup(
+    name = 'jupyter_server_simple',
+    version = VERSION,
+    description = 'Datalayer',
+    long_description = open('README.md').read(),
+    packages = [
+        'jupyter_server_simple',
+    ],
+    package_data = {
+        'jupyter_server_simple': [
+            '*',
+        ],
+    },
+    setup_requires = [
+    ],
+    install_requires = [
+        'jupyter_server==0.2.0.dev0',
+        'jinja2',
+    ],
+    tests_requires = [
+        'pytest',
+        'pytest-cov',
+        'pylint',
+    ],
+    python_requires = '>=3.5',
+    data_files = [
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/server_simple.json']),
+    ],
+    entry_points = {
+        'console_scripts': [
+             'jupyter-server-simple = jupyter_server_simple.application:main'
+        ]
+    },
+)

From 8ea90328105409eadb810ca9924718c616095da5 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Fri, 11 Oct 2019 19:04:56 +0200
Subject: [PATCH 02/30] add typescript example

---
 .gitignore                                    |   3 +-
 examples/simple/Makefile                      |  11 ++
 examples/simple/README.md                     |  32 ++---
 .../{server_simple.json => simple_ext.json}   |   2 +-
 .../simple/jupyter_server_simple/__init__.py  |   8 --
 .../simple/jupyter_server_simple/handler.py   |  11 --
 .../jupyter_server_simple/handler_template.py |  11 --
 .../jupyter_server_simple/static/test.html    |   1 -
 .../templates/server_simple.html              |   5 -
 .../simple/jupyter_simple_ext/__init__.py     |   8 ++
 .../application.py                            |  37 +++---
 .../simple/jupyter_simple_ext/handlers.py     |  38 ++++++
 .../jupyter_simple_ext/static/bundle.js       | 111 ++++++++++++++++++
 .../static/favicon.ico                        | Bin
 .../jupyter_simple_ext/static/index.d.ts      |   1 +
 .../simple/jupyter_simple_ext/static/index.js |   5 +
 .../jupyter_simple_ext/static/test.html       |   1 +
 .../static/tsconfig.tsbuildinfo               |  98 ++++++++++++++++
 .../templates/404.html                        |   0
 .../templates/browser-open.html               |   0
 .../templates/error.html                      |   1 -
 .../jupyter_simple_ext/templates/index.html   |  21 ++++
 .../templates/main.html                       |   0
 .../templates/page.html                       |   0
 .../jupyter_simple_ext/templates/page1.html   |  19 +++
 .../templates/simple_ext.html                 |  21 ++++
 examples/simple/package.json                  |  18 +++
 examples/simple/setup.py                      |  12 +-
 examples/simple/webpack.config.js             |   8 ++
 29 files changed, 407 insertions(+), 76 deletions(-)
 create mode 100644 examples/simple/Makefile
 rename examples/simple/etc/jupyter/jupyter_server_config.d/{server_simple.json => simple_ext.json} (67%)
 delete mode 100644 examples/simple/jupyter_server_simple/__init__.py
 delete mode 100644 examples/simple/jupyter_server_simple/handler.py
 delete mode 100644 examples/simple/jupyter_server_simple/handler_template.py
 delete mode 100644 examples/simple/jupyter_server_simple/static/test.html
 delete mode 100644 examples/simple/jupyter_server_simple/templates/server_simple.html
 create mode 100644 examples/simple/jupyter_simple_ext/__init__.py
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/application.py (53%)
 create mode 100644 examples/simple/jupyter_simple_ext/handlers.py
 create mode 100644 examples/simple/jupyter_simple_ext/static/bundle.js
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/static/favicon.ico (100%)
 create mode 100644 examples/simple/jupyter_simple_ext/static/index.d.ts
 create mode 100644 examples/simple/jupyter_simple_ext/static/index.js
 create mode 100644 examples/simple/jupyter_simple_ext/static/test.html
 create mode 100644 examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/templates/404.html (100%)
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/templates/browser-open.html (100%)
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/templates/error.html (99%)
 create mode 100644 examples/simple/jupyter_simple_ext/templates/index.html
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/templates/main.html (100%)
 rename examples/simple/{jupyter_server_simple => jupyter_simple_ext}/templates/page.html (100%)
 create mode 100644 examples/simple/jupyter_simple_ext/templates/page1.html
 create mode 100644 examples/simple/jupyter_simple_ext/templates/simple_ext.html
 create mode 100644 examples/simple/package.json
 create mode 100644 examples/simple/webpack.config.js

diff --git a/.gitignore b/.gitignore
index 28a83b48fd..b9a436dd76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,7 +15,8 @@ notebook/static/*/built/
 notebook/static/built/
 notebook/static/*/js/main.min.js*
 notebook/static/lab/*bundle.js
-node_modules
+**/node_modules
+**/yarn.lock
 *.py[co]
 __pycache__
 *.egg-info
diff --git a/examples/simple/Makefile b/examples/simple/Makefile
new file mode 100644
index 0000000000..4292cafbb1
--- /dev/null
+++ b/examples/simple/Makefile
@@ -0,0 +1,11 @@
+default: all ## default target is all.
+
+install:
+	yarn install
+	
+build:
+	yarn build
+	pip install -e .
+
+start:
+	jupyter simple-ext
diff --git a/examples/simple/README.md b/examples/simple/README.md
index c6259a12b9..92d0ef9518 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -1,15 +1,18 @@
 # Jupyter Server Simple Extension Example
 
-This folder contains an example to develop an simple extension on top of Jupyter Server.
+This folder contains an example of a simple extension on top of Jupyter Server.
+
+You need yarn and python3.
 
 ```bash
-# Install the server simple extension.
-python setup.py develop
+# Install and build.
+make install
+make build
 ```
 
 ```bash
 # Start the jupyter server simple extension.
-jupyter server-simple
+make start
 ```
 
 Render server content in your browser.
@@ -17,18 +20,17 @@ Render server content in your browser.
 ```bash
 # Default server page.
 open http://localhost:8888
-# Default favicon.
-open http://localhost:8888/favicon.ico
+# Favicon static content.
+open http://localhost:8888/static/simple_ext/favicon.ico
 # HTML static page.
-open http://localhost:8888/static/server_simple/test.html
+open http://localhost:8888/static/simple_ext/test.html
 # Content from Handlers.
-open http://localhost:8888/server_simple
-open http://localhost:8888/server_simple/something?var1=foo
+open http://localhost:8888/simple_ext/params/test?var1=foo
 # Content from Template.
-open http://localhost:8888/template
+open http://localhost:8888/simple_ext/page1/test
+# Content from Template with Typescript.
+open http://localhost:8888/simple_ext
+open http://localhost:8888/simple_ext/template
+# Error content.
+open http://localhost:8888/simple_ext/nope
 ```
-
-## TO FIX
-
-+ The token created in `browser-open.html` is `None` - http://localhost:8888/?token=None
-+ This static favicon request fails with `403 : Forbidden - favicon.ico is not in root static directory` - http://localhost:8888/static/server_simple/favicon.ico
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
similarity index 67%
rename from examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json
rename to examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
index 607ec527aa..f58607d536 100644
--- a/examples/simple/etc/jupyter/jupyter_server_config.d/server_simple.json
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
@@ -1,7 +1,7 @@
 {
     "ServerApp": {
         "jpserver_extensions": {
-            "server_simple": true
+            "simple_ext": true
         }
     }
 }
diff --git a/examples/simple/jupyter_server_simple/__init__.py b/examples/simple/jupyter_server_simple/__init__.py
deleted file mode 100644
index 21752c111f..0000000000
--- a/examples/simple/jupyter_server_simple/__init__.py
+++ /dev/null
@@ -1,8 +0,0 @@
-from .application import ServerSimple
-
-EXTENSION_NAME = "server_simple"
-
-def _jupyter_server_extension_paths():
-    return [{"module": EXTENSION_NAME}]
-
-load_jupyter_server_extension = ServerSimple.load_jupyter_server_extension
diff --git a/examples/simple/jupyter_server_simple/handler.py b/examples/simple/jupyter_server_simple/handler.py
deleted file mode 100644
index d8de78605f..0000000000
--- a/examples/simple/jupyter_server_simple/handler.py
+++ /dev/null
@@ -1,11 +0,0 @@
-from jupyter_server.extension.handler import ExtensionHandler
-
-class ServerSimpleHandler(ExtensionHandler):
-    
-    def get(self, matched_part=None, *args, **kwargs):
-        var1 = self.get_argument('var1', default=None)
-        components = [x for x in self.request.path.split("/") if x]
-        self.write('<h1>Hello Server Simple from Handler.</h1>')
-        self.write('<p>matched_part: {}</p>'.format(matched_part))
-        self.write('<p>var1: {}</p>'.format(var1))
-        self.write('<p>components: {}</p>'.format(components))
diff --git a/examples/simple/jupyter_server_simple/handler_template.py b/examples/simple/jupyter_server_simple/handler_template.py
deleted file mode 100644
index 9966ea22a5..0000000000
--- a/examples/simple/jupyter_server_simple/handler_template.py
+++ /dev/null
@@ -1,11 +0,0 @@
-from jupyter_server.extension.handler import ExtensionHandler
-
-class ServerSimpleTemplateHandler(ExtensionHandler):
-    
-    def get_template(self, name):
-        """Return the jinja template object for a given name"""
-        return self.settings['server_simple_jinja2_env'].get_template(name)
-
-    def get(self):
-#        print(self.get_template('server_simple.html'))
-        self.write(self.render_template('server_simple.html'))
diff --git a/examples/simple/jupyter_server_simple/static/test.html b/examples/simple/jupyter_server_simple/static/test.html
deleted file mode 100644
index 0d8106c290..0000000000
--- a/examples/simple/jupyter_server_simple/static/test.html
+++ /dev/null
@@ -1 +0,0 @@
-<h1>Hello Server Simple from test HTML page.</h1>
diff --git a/examples/simple/jupyter_server_simple/templates/server_simple.html b/examples/simple/jupyter_server_simple/templates/server_simple.html
deleted file mode 100644
index 36190d42c6..0000000000
--- a/examples/simple/jupyter_server_simple/templates/server_simple.html
+++ /dev/null
@@ -1,5 +0,0 @@
-{% extends "page.html" %}
-
-{% block site %}
-<h1>Hello Server Simple from Template.</h1>
-{% endblock site %}
diff --git a/examples/simple/jupyter_simple_ext/__init__.py b/examples/simple/jupyter_simple_ext/__init__.py
new file mode 100644
index 0000000000..41a687982b
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/__init__.py
@@ -0,0 +1,8 @@
+from .application import SimpleServer
+
+EXTENSION_NAME = "simple_ext"
+
+def _jupyter_server_extension_paths():
+    return [{"module": EXTENSION_NAME}]
+
+load_jupyter_server_extension = SimpleServer.load_jupyter_server_extension
diff --git a/examples/simple/jupyter_server_simple/application.py b/examples/simple/jupyter_simple_ext/application.py
similarity index 53%
rename from examples/simple/jupyter_server_simple/application.py
rename to examples/simple/jupyter_simple_ext/application.py
index 430baa8167..8ff8c5ed68 100644
--- a/examples/simple/jupyter_server_simple/application.py
+++ b/examples/simple/jupyter_simple_ext/application.py
@@ -1,15 +1,22 @@
 import os, jinja2
-from .handler import ServerSimpleHandler
-from .handler_template import ServerSimpleTemplateHandler
 from jupyter_server.extension.application import ExtensionApp
+from .handlers import ParameterHandler, TemplateHandler, Page1Handler, IndexHandler, ErrorHandler
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-class ServerSimple(ExtensionApp):
+print(DEFAULT_TEMPLATE_FILES_PATH)
+
+class SimpleServer(ExtensionApp):
     
-    # Name of the extension
-    extension_name = "server_simple"
+    # The name of the extension
+    extension_name = "simple_ext"
+
+    # default_url: the url that your extension will serve its homepage.
+    default_url = '/simple_ext'
+
+    # load_other_extensions: should your extension expose other server extensions when launched directly?
+    load_other_extensions = True
 
     # Local path to static files directory.
     static_paths = [
@@ -22,15 +29,13 @@ class ServerSimple(ExtensionApp):
     ]
 
     def initialize_handlers(self):
-        self.handlers.append(
-            (r'/server_simple', ServerSimpleHandler, {})
-        )
-        self.handlers.append(
-            (r'/server_simple/(.+)$', ServerSimpleHandler, {})
-        )
-        self.handlers.append(
-            (r'/template', ServerSimpleTemplateHandler, {})
-        )
+        self.handlers.extend([
+            (r'/simple_ext/params/(.+)$', ParameterHandler),
+            (r'/simple_ext/template', TemplateHandler),
+            (r'/simple_ext/page1/(.*)$', Page1Handler),
+            (r'/simple_ext/?', IndexHandler),
+            (r'/simple_ext/(.*)', ErrorHandler)
+        ])
 
     def initialize_templates(self):
         jenv_opt = {"autoescape": True}
@@ -39,7 +44,7 @@ def initialize_templates(self):
             extensions=["jinja2.ext.i18n"],
             **jenv_opt
         )
-        template_settings = {"server_simple_jinja2_env": env}
+        template_settings = {"simple_ext_jinja2_env": env}
         self.settings.update(**template_settings)
 
     def initialize_settings(self):
@@ -49,4 +54,4 @@ def initialize_settings(self):
 # Main entry point
 #-----------------------------------------------------------------------------
 
-main = launch_new_instance = ServerSimple.launch_instance
+main = launch_new_instance = SimpleServer.launch_instance
diff --git a/examples/simple/jupyter_simple_ext/handlers.py b/examples/simple/jupyter_simple_ext/handlers.py
new file mode 100644
index 0000000000..b5b92cf499
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/handlers.py
@@ -0,0 +1,38 @@
+from jupyter_server.extension.handler import ExtensionHandler
+
+class TemplateHandler(ExtensionHandler):
+
+    def get_template(self, name):
+        """Return the jinja template object for a given name"""
+        return self.settings['simple_ext_jinja2_env'].get_template(name)
+
+class IndexHandler(TemplateHandler):
+    
+    def get(self):
+        self.write(self.render_template("index.html"))
+
+class ParameterHandler(TemplateHandler):
+    
+    def get(self, matched_part=None, *args, **kwargs):
+        var1 = self.get_argument('var1', default=None)
+        components = [x for x in self.request.path.split("/") if x]
+        self.write('<h1>Hello Simple Server from Handler.</h1>')
+        self.write('<p>matched_part: {}</p>'.format(matched_part))
+        self.write('<p>var1: {}</p>'.format(var1))
+        self.write('<p>components: {}</p>'.format(components))
+
+class TemplateHandler(TemplateHandler):
+    
+    def get(self):
+        print(self.get_template('simple_ext.html'))
+        self.write(self.render_template('simple_ext.html'))
+
+class Page1Handler(TemplateHandler):
+    
+    def get(self, path):
+        self.write(self.render_template('page1.html', text=path))
+
+class ErrorHandler(TemplateHandler):
+    
+    def get(self, path):
+        self.write(self.render_template('error.html'))
diff --git a/examples/simple/jupyter_simple_ext/static/bundle.js b/examples/simple/jupyter_simple_ext/static/bundle.js
new file mode 100644
index 0000000000..eedfa23390
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/static/bundle.js
@@ -0,0 +1,111 @@
+/******/ (function(modules) { // webpackBootstrap
+/******/ 	// The module cache
+/******/ 	var installedModules = {};
+/******/
+/******/ 	// The require function
+/******/ 	function __webpack_require__(moduleId) {
+/******/
+/******/ 		// Check if module is in cache
+/******/ 		if(installedModules[moduleId]) {
+/******/ 			return installedModules[moduleId].exports;
+/******/ 		}
+/******/ 		// Create a new module (and put it into the cache)
+/******/ 		var module = installedModules[moduleId] = {
+/******/ 			i: moduleId,
+/******/ 			l: false,
+/******/ 			exports: {}
+/******/ 		};
+/******/
+/******/ 		// Execute the module function
+/******/ 		modules[moduleId].call(module.exports, module, module.exports, __webpack_require__);
+/******/
+/******/ 		// Flag the module as loaded
+/******/ 		module.l = true;
+/******/
+/******/ 		// Return the exports of the module
+/******/ 		return module.exports;
+/******/ 	}
+/******/
+/******/
+/******/ 	// expose the modules object (__webpack_modules__)
+/******/ 	__webpack_require__.m = modules;
+/******/
+/******/ 	// expose the module cache
+/******/ 	__webpack_require__.c = installedModules;
+/******/
+/******/ 	// define getter function for harmony exports
+/******/ 	__webpack_require__.d = function(exports, name, getter) {
+/******/ 		if(!__webpack_require__.o(exports, name)) {
+/******/ 			Object.defineProperty(exports, name, { enumerable: true, get: getter });
+/******/ 		}
+/******/ 	};
+/******/
+/******/ 	// define __esModule on exports
+/******/ 	__webpack_require__.r = function(exports) {
+/******/ 		if(typeof Symbol !== 'undefined' && Symbol.toStringTag) {
+/******/ 			Object.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });
+/******/ 		}
+/******/ 		Object.defineProperty(exports, '__esModule', { value: true });
+/******/ 	};
+/******/
+/******/ 	// create a fake namespace object
+/******/ 	// mode & 1: value is a module id, require it
+/******/ 	// mode & 2: merge all properties of value into the ns
+/******/ 	// mode & 4: return value when already ns object
+/******/ 	// mode & 8|1: behave like require
+/******/ 	__webpack_require__.t = function(value, mode) {
+/******/ 		if(mode & 1) value = __webpack_require__(value);
+/******/ 		if(mode & 8) return value;
+/******/ 		if((mode & 4) && typeof value === 'object' && value && value.__esModule) return value;
+/******/ 		var ns = Object.create(null);
+/******/ 		__webpack_require__.r(ns);
+/******/ 		Object.defineProperty(ns, 'default', { enumerable: true, value: value });
+/******/ 		if(mode & 2 && typeof value != 'string') for(var key in value) __webpack_require__.d(ns, key, function(key) { return value[key]; }.bind(null, key));
+/******/ 		return ns;
+/******/ 	};
+/******/
+/******/ 	// getDefaultExport function for compatibility with non-harmony modules
+/******/ 	__webpack_require__.n = function(module) {
+/******/ 		var getter = module && module.__esModule ?
+/******/ 			function getDefault() { return module['default']; } :
+/******/ 			function getModuleExports() { return module; };
+/******/ 		__webpack_require__.d(getter, 'a', getter);
+/******/ 		return getter;
+/******/ 	};
+/******/
+/******/ 	// Object.prototype.hasOwnProperty.call
+/******/ 	__webpack_require__.o = function(object, property) { return Object.prototype.hasOwnProperty.call(object, property); };
+/******/
+/******/ 	// __webpack_public_path__
+/******/ 	__webpack_require__.p = "";
+/******/
+/******/
+/******/ 	// Load entry module and return exports
+/******/ 	return __webpack_require__(__webpack_require__.s = 0);
+/******/ })
+/************************************************************************/
+/******/ ({
+
+/***/ "./jupyter_simple_ext/static/index.js":
+/*!********************************************!*\
+  !*** ./jupyter_simple_ext/static/index.js ***!
+  \********************************************/
+/*! no static exports found */
+/***/ (function(module, exports) {
+
+eval("function main() {\n    let div = document.getElementById(\"mydiv\");\n    div.innerText = \"<h1>Hello from Typescript</h1>\";\n}\nwindow.addEventListener('load', main);\n\n\n//# sourceURL=webpack:///./jupyter_simple_ext/static/index.js?");
+
+/***/ }),
+
+/***/ 0:
+/*!**************************************************!*\
+  !*** multi ./jupyter_simple_ext/static/index.js ***!
+  \**************************************************/
+/*! no static exports found */
+/***/ (function(module, exports, __webpack_require__) {
+
+eval("module.exports = __webpack_require__(/*! ./jupyter_simple_ext/static/index.js */\"./jupyter_simple_ext/static/index.js\");\n\n\n//# sourceURL=webpack:///multi_./jupyter_simple_ext/static/index.js?");
+
+/***/ })
+
+/******/ });
\ No newline at end of file
diff --git a/examples/simple/jupyter_server_simple/static/favicon.ico b/examples/simple/jupyter_simple_ext/static/favicon.ico
similarity index 100%
rename from examples/simple/jupyter_server_simple/static/favicon.ico
rename to examples/simple/jupyter_simple_ext/static/favicon.ico
diff --git a/examples/simple/jupyter_simple_ext/static/index.d.ts b/examples/simple/jupyter_simple_ext/static/index.d.ts
new file mode 100644
index 0000000000..1be3002bfe
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/static/index.d.ts
@@ -0,0 +1 @@
+declare function main(): void;
diff --git a/examples/simple/jupyter_simple_ext/static/index.js b/examples/simple/jupyter_simple_ext/static/index.js
new file mode 100644
index 0000000000..b18e39c21d
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/static/index.js
@@ -0,0 +1,5 @@
+function main() {
+    let div = document.getElementById("mydiv");
+    div.innerText = "<h1>Hello from Typescript</h1>";
+}
+window.addEventListener('load', main);
diff --git a/examples/simple/jupyter_simple_ext/static/test.html b/examples/simple/jupyter_simple_ext/static/test.html
new file mode 100644
index 0000000000..7426bcb9c6
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/static/test.html
@@ -0,0 +1 @@
+<h1>Hello Simple Server from test HTML page.</h1>
diff --git a/examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo b/examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo
new file mode 100644
index 0000000000..bd022041a6
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo
@@ -0,0 +1,98 @@
+{
+  "program": {
+    "fileInfos": {
+      "../../node_modules/typescript/lib/lib.es5.d.ts": {
+        "version": "ff5688d6b2fcfef06842a395d7ff4d5730d45b724d4c48913118c889829052a1",
+        "signature": "ff5688d6b2fcfef06842a395d7ff4d5730d45b724d4c48913118c889829052a1"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.d.ts": {
+        "version": "7994d44005046d1413ea31d046577cdda33b8b2470f30281fd9c8b3c99fe2d96",
+        "signature": "7994d44005046d1413ea31d046577cdda33b8b2470f30281fd9c8b3c99fe2d96"
+      },
+      "../../node_modules/typescript/lib/lib.dom.d.ts": {
+        "version": "2d53f3741e5a4f78a90f623387d71a1cc809bb258f10cdaec034b67cbf71022f",
+        "signature": "2d53f3741e5a4f78a90f623387d71a1cc809bb258f10cdaec034b67cbf71022f"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.core.d.ts": {
+        "version": "4ab19088d508f9e62bfc61c157e8a65b2afaefa251ecca315e7d20b5b97b256f",
+        "signature": "4ab19088d508f9e62bfc61c157e8a65b2afaefa251ecca315e7d20b5b97b256f"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.collection.d.ts": {
+        "version": "dd94d8ef48c562389eb58af8df3a3a34d11367f7c818192aa5f16470d469e3f0",
+        "signature": "dd94d8ef48c562389eb58af8df3a3a34d11367f7c818192aa5f16470d469e3f0"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.generator.d.ts": {
+        "version": "765e0e9c9d74cf4d031ca8b0bdb269a853e7d81eda6354c8510218d03db12122",
+        "signature": "765e0e9c9d74cf4d031ca8b0bdb269a853e7d81eda6354c8510218d03db12122"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.iterable.d.ts": {
+        "version": "285958e7699f1babd76d595830207f18d719662a0c30fac7baca7df7162a9210",
+        "signature": "285958e7699f1babd76d595830207f18d719662a0c30fac7baca7df7162a9210"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.promise.d.ts": {
+        "version": "e6b8ff2798f8ebd7a1c7afd8671f2cb67ee1901c422f5964d74b0b34c6574ea2",
+        "signature": "e6b8ff2798f8ebd7a1c7afd8671f2cb67ee1901c422f5964d74b0b34c6574ea2"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.proxy.d.ts": {
+        "version": "5e72f949a89717db444e3bd9433468890068bb21a5638d8ab15a1359e05e54fe",
+        "signature": "5e72f949a89717db444e3bd9433468890068bb21a5638d8ab15a1359e05e54fe"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.reflect.d.ts": {
+        "version": "f5b242136ae9bfb1cc99a5971cccc44e99947ae6b5ef6fd8aa54b5ade553b976",
+        "signature": "f5b242136ae9bfb1cc99a5971cccc44e99947ae6b5ef6fd8aa54b5ade553b976"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.symbol.d.ts": {
+        "version": "9ae2860252d6b5f16e2026d8a2c2069db7b2a3295e98b6031d01337b96437230",
+        "signature": "9ae2860252d6b5f16e2026d8a2c2069db7b2a3295e98b6031d01337b96437230"
+      },
+      "../../node_modules/typescript/lib/lib.es2015.symbol.wellknown.d.ts": {
+        "version": "3e0a459888f32b42138d5a39f706ff2d55d500ab1031e0988b5568b0f67c2303",
+        "signature": "3e0a459888f32b42138d5a39f706ff2d55d500ab1031e0988b5568b0f67c2303"
+      },
+      "../../src/index.ts": {
+        "version": "03d69b24d41bd5bd41aecc996c31b8e908696cebbae569924ed26916a10924a9",
+        "signature": "ed4b087ea2a2e4a58647864cf512c7534210bfc2f9d236a2f9ed5245cf7a0896"
+      }
+    },
+    "options": {
+      "outDir": "./",
+      "allowSyntheticDefaultImports": true,
+      "composite": true,
+      "declaration": true,
+      "noImplicitAny": true,
+      "noEmitOnError": true,
+      "noUnusedLocals": true,
+      "esModuleInterop": true,
+      "preserveWatchOutput": true,
+      "module": 1,
+      "moduleResolution": 2,
+      "target": 2,
+      "lib": [
+        "lib.dom.d.ts",
+        "lib.es2015.d.ts"
+      ],
+      "jsx": 2,
+      "types": [],
+      "project": "../../src",
+      "configFilePath": "../../src/tsconfig.json"
+    },
+    "referencedMap": {},
+    "exportedModulesMap": {},
+    "semanticDiagnosticsPerFile": [
+      "../../node_modules/typescript/lib/lib.es5.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.d.ts",
+      "../../node_modules/typescript/lib/lib.dom.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.core.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.collection.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.generator.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.iterable.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.promise.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.proxy.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.reflect.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.symbol.d.ts",
+      "../../node_modules/typescript/lib/lib.es2015.symbol.wellknown.d.ts",
+      "../../src/index.ts"
+    ]
+  },
+  "version": "3.6.4"
+}
\ No newline at end of file
diff --git a/examples/simple/jupyter_server_simple/templates/404.html b/examples/simple/jupyter_simple_ext/templates/404.html
similarity index 100%
rename from examples/simple/jupyter_server_simple/templates/404.html
rename to examples/simple/jupyter_simple_ext/templates/404.html
diff --git a/examples/simple/jupyter_server_simple/templates/browser-open.html b/examples/simple/jupyter_simple_ext/templates/browser-open.html
similarity index 100%
rename from examples/simple/jupyter_server_simple/templates/browser-open.html
rename to examples/simple/jupyter_simple_ext/templates/browser-open.html
diff --git a/examples/simple/jupyter_server_simple/templates/error.html b/examples/simple/jupyter_simple_ext/templates/error.html
similarity index 99%
rename from examples/simple/jupyter_server_simple/templates/error.html
rename to examples/simple/jupyter_simple_ext/templates/error.html
index 1e3fae6225..7426beb571 100644
--- a/examples/simple/jupyter_server_simple/templates/error.html
+++ b/examples/simple/jupyter_simple_ext/templates/error.html
@@ -18,4 +18,3 @@ <h1>{{status_code}} : {{status_message}}</h1>
 </div>
 
 {% endblock %}
-
diff --git a/examples/simple/jupyter_simple_ext/templates/index.html b/examples/simple/jupyter_simple_ext/templates/index.html
new file mode 100644
index 0000000000..e825cf31cb
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/templates/index.html
@@ -0,0 +1,21 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <script src="{{static_url('bundle.js')}}" type="text/javascript" charset="utf-8"></script>
+  <script type="text/javascript">
+    /* Remove token from URL. */
+    (function () {
+      var parsedUrl = new URL(window.location.href);
+      if (parsedUrl.searchParams.get('token')) {
+        parsedUrl.searchParams.delete('token');
+        window.history.replaceState({ }, '', parsedUrl.href);
+      }
+    })();
+  </script>
+</head>
+<body>
+  <div id="mydiv">
+  <h1>Hello world! </h1>
+  </div>
+</body>
diff --git a/examples/simple/jupyter_server_simple/templates/main.html b/examples/simple/jupyter_simple_ext/templates/main.html
similarity index 100%
rename from examples/simple/jupyter_server_simple/templates/main.html
rename to examples/simple/jupyter_simple_ext/templates/main.html
diff --git a/examples/simple/jupyter_server_simple/templates/page.html b/examples/simple/jupyter_simple_ext/templates/page.html
similarity index 100%
rename from examples/simple/jupyter_server_simple/templates/page.html
rename to examples/simple/jupyter_simple_ext/templates/page.html
diff --git a/examples/simple/jupyter_simple_ext/templates/page1.html b/examples/simple/jupyter_simple_ext/templates/page1.html
new file mode 100644
index 0000000000..7fba4842ae
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/templates/page1.html
@@ -0,0 +1,19 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <script type="text/javascript">
+    /* Remove token from URL. */
+    (function () {
+      var parsedUrl = new URL(window.location.href);
+      if (parsedUrl.searchParams.get('token')) {
+        parsedUrl.searchParams.delete('token');
+        window.history.replaceState({ }, '', parsedUrl.href);
+      }
+    })();
+  </script>
+</head>
+<body>
+  <h1>Hello from Page 1 Template.</h1>
+  <p>Path: {{text}}</p>
+</body>
diff --git a/examples/simple/jupyter_simple_ext/templates/simple_ext.html b/examples/simple/jupyter_simple_ext/templates/simple_ext.html
new file mode 100644
index 0000000000..e825cf31cb
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext/templates/simple_ext.html
@@ -0,0 +1,21 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <script src="{{static_url('bundle.js')}}" type="text/javascript" charset="utf-8"></script>
+  <script type="text/javascript">
+    /* Remove token from URL. */
+    (function () {
+      var parsedUrl = new URL(window.location.href);
+      if (parsedUrl.searchParams.get('token')) {
+        parsedUrl.searchParams.delete('token');
+        window.history.replaceState({ }, '', parsedUrl.href);
+      }
+    })();
+  </script>
+</head>
+<body>
+  <div id="mydiv">
+  <h1>Hello world! </h1>
+  </div>
+</body>
diff --git a/examples/simple/package.json b/examples/simple/package.json
new file mode 100644
index 0000000000..26ae47510f
--- /dev/null
+++ b/examples/simple/package.json
@@ -0,0 +1,18 @@
+{
+  "name": "jupyter-server-simple-ext",
+  "version": "0.0.1",
+  "private": true,
+  "scripts": {
+    "build": "tsc -p src && webpack",
+    "clean": "rimraf build",
+    "prepublishOnly": "npm run build"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "rifraf": "2.0.3",
+    "webpack": "~4.29.6",
+    "webpack-cli": "^3.3.0",
+    "whatwg-fetch": "~2.0.3",
+    "typescript": "3.6.4"
+  }
+}
diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index 9ef276ee28..c2eacc8dbe 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -3,22 +3,22 @@
 VERSION = '0.0.1'
 
 setuptools.setup(
-    name = 'jupyter_server_simple',
+    name = 'jupyter_simple_ext',
     version = VERSION,
     description = 'Datalayer',
     long_description = open('README.md').read(),
     packages = [
-        'jupyter_server_simple',
+        'jupyter_simple_ext',
     ],
     package_data = {
-        'jupyter_server_simple': [
+        'jupyter_simple_ext': [
             '*',
         ],
     },
     setup_requires = [
     ],
     install_requires = [
-        'jupyter_server==0.2.0.dev0',
+        'jupyter_server==0.1.1',
         'jinja2',
     ],
     tests_requires = [
@@ -28,11 +28,11 @@
     ],
     python_requires = '>=3.5',
     data_files = [
-        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/server_simple.json']),
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext.json']),
     ],
     entry_points = {
         'console_scripts': [
-             'jupyter-server-simple = jupyter_server_simple.application:main'
+             'jupyter-simple-ext = jupyter_simple_ext.application:main'
         ]
     },
 )
diff --git a/examples/simple/webpack.config.js b/examples/simple/webpack.config.js
new file mode 100644
index 0000000000..f39d5e004c
--- /dev/null
+++ b/examples/simple/webpack.config.js
@@ -0,0 +1,8 @@
+module.exports = {
+  entry: ['./jupyter_simple_ext/static/index.js'],
+  output: {
+    path: require('path').join(__dirname, 'jupyter_simple_ext', 'static'),
+    filename: 'bundle.js'
+  },
+  mode: 'development'
+}

From ec3d1968ad92eb560e6b6eba591d1a841da5c651 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Fri, 11 Oct 2019 19:07:50 +0200
Subject: [PATCH 03/30] force pr refresh

---
 examples/simple/test | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 examples/simple/test

diff --git a/examples/simple/test b/examples/simple/test
new file mode 100644
index 0000000000..e69de29bb2

From de57ab24ff5a7d815590889805737698a6f2414c Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Fri, 11 Oct 2019 19:08:03 +0200
Subject: [PATCH 04/30] force pr refresh

---
 examples/simple/test | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 delete mode 100644 examples/simple/test

diff --git a/examples/simple/test b/examples/simple/test
deleted file mode 100644
index e69de29bb2..0000000000

From 51c3a65ce1246a89d5c82424b3ee736cab0b60f8 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 12 Oct 2019 10:30:45 +0200
Subject: [PATCH 05/30] 2 apps

---
 .gitignore                                    |   4 +-
 examples/simple/Makefile                      |  29 +++++--
 examples/simple/README.md                     |  72 ++++++++++++++----
 .../jupyter_server_config.d/simple_ext.json   |   3 +-
 .../simple/jupyter_simple_ext/__init__.py     |   8 --
 .../jupyter_simple_ext/static/test.html       |   1 -
 .../jupyter_simple_ext/templates/404.html     |   5 --
 .../templates/browser-open.html               |  18 -----
 .../jupyter_simple_ext/templates/main.html    |   5 --
 examples/simple/package.json                  |   2 +-
 examples/simple/setup.py                      |  44 ++++++-----
 examples/simple/simple_ext1/__init__.py       |   8 ++
 .../application.py                            |  26 +++----
 .../handlers.py                               |  10 +--
 .../static/bundle.js                          |  18 ++---
 .../static/favicon.ico                        | Bin
 .../static/index.d.ts                         |   0
 .../static/index.js                           |   2 +-
 examples/simple/simple_ext1/static/test.html  |   1 +
 .../static/tsconfig.tsbuildinfo               |   2 +-
 .../templates/error.html                      |   0
 .../templates/index.html                      |   0
 .../templates/page.html                       |   0
 .../templates/page1.html                      |   0
 .../templates/simple_ext1.html}               |   0
 examples/simple/simple_ext2/__init__.py       |   8 ++
 examples/simple/simple_ext2/application.py    |  56 ++++++++++++++
 examples/simple/simple_ext2/handlers.py       |  33 ++++++++
 .../simple/simple_ext2/static/favicon.ico     | Bin 0 -> 32038 bytes
 examples/simple/simple_ext2/static/test.html  |   1 +
 .../simple/simple_ext2/templates/error.html   |  20 +++++
 .../simple/simple_ext2/templates/index.html   |   1 +
 .../simple/simple_ext2/templates/page.html    |  20 +++++
 .../simple_ext2/templates/simple_ext2.html    |   1 +
 examples/simple/webpack.config.js             |   4 +-
 35 files changed, 292 insertions(+), 110 deletions(-)
 delete mode 100644 examples/simple/jupyter_simple_ext/__init__.py
 delete mode 100644 examples/simple/jupyter_simple_ext/static/test.html
 delete mode 100644 examples/simple/jupyter_simple_ext/templates/404.html
 delete mode 100644 examples/simple/jupyter_simple_ext/templates/browser-open.html
 delete mode 100644 examples/simple/jupyter_simple_ext/templates/main.html
 create mode 100644 examples/simple/simple_ext1/__init__.py
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/application.py (63%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/handlers.py (77%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/static/bundle.js (83%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/static/favicon.ico (100%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/static/index.d.ts (100%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/static/index.js (66%)
 create mode 100644 examples/simple/simple_ext1/static/test.html
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/static/tsconfig.tsbuildinfo (98%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/templates/error.html (100%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/templates/index.html (100%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/templates/page.html (100%)
 rename examples/simple/{jupyter_simple_ext => simple_ext1}/templates/page1.html (100%)
 rename examples/simple/{jupyter_simple_ext/templates/simple_ext.html => simple_ext1/templates/simple_ext1.html} (100%)
 create mode 100644 examples/simple/simple_ext2/__init__.py
 create mode 100644 examples/simple/simple_ext2/application.py
 create mode 100644 examples/simple/simple_ext2/handlers.py
 create mode 100644 examples/simple/simple_ext2/static/favicon.ico
 create mode 100644 examples/simple/simple_ext2/static/test.html
 create mode 100644 examples/simple/simple_ext2/templates/error.html
 create mode 100644 examples/simple/simple_ext2/templates/index.html
 create mode 100644 examples/simple/simple_ext2/templates/page.html
 create mode 100644 examples/simple/simple_ext2/templates/simple_ext2.html

diff --git a/.gitignore b/.gitignore
index b9a436dd76..5f0aa534df 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,8 +15,7 @@ notebook/static/*/built/
 notebook/static/built/
 notebook/static/*/js/main.min.js*
 notebook/static/lab/*bundle.js
-**/node_modules
-**/yarn.lock
+node_modules
 *.py[co]
 __pycache__
 *.egg-info
@@ -42,3 +41,4 @@ config.rst
 
 package-lock.json
 geckodriver.log
+yarn.lock
diff --git a/examples/simple/Makefile b/examples/simple/Makefile
index 4292cafbb1..b7324ebfd0 100644
--- a/examples/simple/Makefile
+++ b/examples/simple/Makefile
@@ -1,11 +1,28 @@
-default: all ## default target is all.
+.PHONY: clean build install uninstall
 
-install:
-	yarn install
+clean:
+	npm clean
+
+install-ts:
+	npm install
 	
+build-ts:
+	npm run build
+
 build:
-	yarn build
 	pip install -e .
 
-start:
-	jupyter simple-ext
+install:
+	python setup.py install
+
+uninstall:
+	pip uninstall -y simple_ext
+
+start1+2:
+	jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
+
+start1:
+	jupyter simple-ext1
+
+start2:
+	jupyter simple-ext2
diff --git a/examples/simple/README.md b/examples/simple/README.md
index 92d0ef9518..766869b98e 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -1,36 +1,80 @@
 # Jupyter Server Simple Extension Example
 
-This folder contains an example of a simple extension on top of Jupyter Server.
+This folder contains an example of 2 simple extensions on top of Jupyter Server.
 
-You need yarn and python3.
+OPTIONAL (compiled js is provided) If you want to build the typescript code, you need npm installed.
 
 ```bash
-# Install and build.
-make install
+make install-ts
+make build-ts
+```
+
+You need python3 to build and run the extensions.
+
+```bash
+conda create -y -n jext python=3.7
+conda activate jext
 make build
 ```
 
 ```bash
-# Start the jupyter server simple extension.
-make start
+# Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
+make start1+2
+```
+
+Optionally, you can copy `simple_ext.json` configuration to your env `etc` folder and start only App 1.
+
+```bash
+make uninstall
+make install
+cp -r ./etc $(dirname $(which jupyter))/..
+# Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
+make start1
 ```
 
-Render server content in your browser.
+Render default Server content in your browser.
 
 ```bash
 # Default server page.
 open http://localhost:8888
+```
+
+Render Extension 1 Server content in your browser.
+
+```bash
 # Favicon static content.
-open http://localhost:8888/static/simple_ext/favicon.ico
+open http://localhost:8888/static/simple_ext1/favicon.ico
 # HTML static page.
-open http://localhost:8888/static/simple_ext/test.html
+open http://localhost:8888/static/simple_ext1/test.html
 # Content from Handlers.
-open http://localhost:8888/simple_ext/params/test?var1=foo
+open http://localhost:8888/simple_ext1/params/test?var1=foo
 # Content from Template.
-open http://localhost:8888/simple_ext/page1/test
+open http://localhost:8888/simple_ext1/page1/test
 # Content from Template with Typescript.
-open http://localhost:8888/simple_ext
-open http://localhost:8888/simple_ext/template
+open http://localhost:8888/simple_ext1
+open http://localhost:8888/simple_ext1/template
 # Error content.
-open http://localhost:8888/simple_ext/nope
+open http://localhost:8888/simple_ext1/nope
 ```
+
+Render Extension 2 Server content in your browser.
+
+```bash
+# HTML static page.
+open http://localhost:8888/static/simple_ext2/test.html
+# Content from Handlers.
+open http://localhost:8888/simple_ext2/params/test?var1=foo
+```
+
+Now stop the server and start again with only Extension 2.
+
+```bash
+# Start the jupyter server extension simple_ext2, it will NOT load simple_ext1 because of load_other_extensions = False.
+make start2
+```
+
+Try with the above links to check that only Extension 2 is responding.
+
+## TODO
+
++ Automatic redirect on the default home page.
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
index f58607d536..b3e2f07b59 100644
--- a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
@@ -1,7 +1,8 @@
 {
     "ServerApp": {
         "jpserver_extensions": {
-            "simple_ext": true
+            "simple_ext1": true,
+            "simple_ext2": true
         }
     }
 }
diff --git a/examples/simple/jupyter_simple_ext/__init__.py b/examples/simple/jupyter_simple_ext/__init__.py
deleted file mode 100644
index 41a687982b..0000000000
--- a/examples/simple/jupyter_simple_ext/__init__.py
+++ /dev/null
@@ -1,8 +0,0 @@
-from .application import SimpleServer
-
-EXTENSION_NAME = "simple_ext"
-
-def _jupyter_server_extension_paths():
-    return [{"module": EXTENSION_NAME}]
-
-load_jupyter_server_extension = SimpleServer.load_jupyter_server_extension
diff --git a/examples/simple/jupyter_simple_ext/static/test.html b/examples/simple/jupyter_simple_ext/static/test.html
deleted file mode 100644
index 7426bcb9c6..0000000000
--- a/examples/simple/jupyter_simple_ext/static/test.html
+++ /dev/null
@@ -1 +0,0 @@
-<h1>Hello Simple Server from test HTML page.</h1>
diff --git a/examples/simple/jupyter_simple_ext/templates/404.html b/examples/simple/jupyter_simple_ext/templates/404.html
deleted file mode 100644
index e29646af1a..0000000000
--- a/examples/simple/jupyter_simple_ext/templates/404.html
+++ /dev/null
@@ -1,5 +0,0 @@
-{% extends "error.html" %}
-{% block error_detail %}
-<p>{% trans %}You are requesting a page that does not exist!{% endtrans %}</p>
-{% endblock %}
-
diff --git a/examples/simple/jupyter_simple_ext/templates/browser-open.html b/examples/simple/jupyter_simple_ext/templates/browser-open.html
deleted file mode 100644
index 6f277967fc..0000000000
--- a/examples/simple/jupyter_simple_ext/templates/browser-open.html
+++ /dev/null
@@ -1,18 +0,0 @@
-{# This template is not served, but written as a file to open in the browser,
-   passing the token without putting it in a command-line argument. #}
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta http-equiv="refresh" content="1;url={{ open_url }}" />
-    <title>Opening Jupyter Notebook</title>
-</head>
-<body>
-
-<p>
-    This page should redirect you to Jupyter Notebook. If it doesn't,
-    <a href="{{ open_url }}">click here to go to Jupyter</a>.
-</p>
-
-</body>
-</html>
diff --git a/examples/simple/jupyter_simple_ext/templates/main.html b/examples/simple/jupyter_simple_ext/templates/main.html
deleted file mode 100644
index 51f8be1c07..0000000000
--- a/examples/simple/jupyter_simple_ext/templates/main.html
+++ /dev/null
@@ -1,5 +0,0 @@
-{% extends "page.html" %}
-
-{% block site %}
-<h1>Server 1 is running.</h1>
-{% endblock site %}
diff --git a/examples/simple/package.json b/examples/simple/package.json
index 26ae47510f..a1b2132753 100644
--- a/examples/simple/package.json
+++ b/examples/simple/package.json
@@ -1,5 +1,5 @@
 {
-  "name": "jupyter-server-simple-ext",
+  "name": "jupyter-simple-ext",
   "version": "0.0.1",
   "private": true,
   "scripts": {
diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index c2eacc8dbe..a2e78122df 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -1,22 +1,32 @@
-import setuptools
+import os, setuptools
+from setuptools import find_packages
 
 VERSION = '0.0.1'
 
+def get_data_files():
+    """Get the data files for the package.
+    """
+    data_files = [
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext.json']),
+    ]
+    def add_data_files(path):
+        for (dirpath, dirnames, filenames) in os.walk(path):
+            if filenames:
+                data_files.append((dirpath, [os.path.join(dirpath, filename) for filename in filenames]))
+    # Add all the templates
+    add_data_files('simple_ext1/static')
+    add_data_files('simple_ext1/templates')
+    add_data_files('simple_ext2/static')
+    add_data_files('simple_ext2/templates')
+    return data_files
+
 setuptools.setup(
-    name = 'jupyter_simple_ext',
+    name = 'simple_ext',
     version = VERSION,
-    description = 'Datalayer',
+    description = 'Jupyter Simple Extension',
     long_description = open('README.md').read(),
-    packages = [
-        'jupyter_simple_ext',
-    ],
-    package_data = {
-        'jupyter_simple_ext': [
-            '*',
-        ],
-    },
-    setup_requires = [
-    ],
+    packages = find_packages(),
+    python_requires = '>=3.5',
     install_requires = [
         'jupyter_server==0.1.1',
         'jinja2',
@@ -26,13 +36,11 @@
         'pytest-cov',
         'pylint',
     ],
-    python_requires = '>=3.5',
-    data_files = [
-        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext.json']),
-    ],
+    data_files = get_data_files(),
     entry_points = {
         'console_scripts': [
-             'jupyter-simple-ext = jupyter_simple_ext.application:main'
+             'jupyter-simple-ext1 = simple_ext1.application:main',
+             'jupyter-simple-ext2 = simple_ext2.application:main'
         ]
     },
 )
diff --git a/examples/simple/simple_ext1/__init__.py b/examples/simple/simple_ext1/__init__.py
new file mode 100644
index 0000000000..cf3068ed96
--- /dev/null
+++ b/examples/simple/simple_ext1/__init__.py
@@ -0,0 +1,8 @@
+from .application import SimpleApp1
+
+def _jupyter_server_extension_paths():
+    return [
+        {'module': 'simple_ext1'}
+    ]
+
+load_jupyter_server_extension = SimpleApp1.load_jupyter_server_extension
diff --git a/examples/simple/jupyter_simple_ext/application.py b/examples/simple/simple_ext1/application.py
similarity index 63%
rename from examples/simple/jupyter_simple_ext/application.py
rename to examples/simple/simple_ext1/application.py
index 8ff8c5ed68..4a6c74965e 100644
--- a/examples/simple/jupyter_simple_ext/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -5,17 +5,17 @@
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-print(DEFAULT_TEMPLATE_FILES_PATH)
+print('--- {}'.format(DEFAULT_STATIC_FILES_PATH))
 
-class SimpleServer(ExtensionApp):
+class SimpleApp1(ExtensionApp):
     
     # The name of the extension
-    extension_name = "simple_ext"
+    extension_name = "simple_ext1"
 
-    # default_url: the url that your extension will serve its homepage.
-    default_url = '/simple_ext'
+    # Te url that your extension will serve its homepage.
+    default_url = '/simple_ext1'
 
-    # load_other_extensions: should your extension expose other server extensions when launched directly?
+    # Should your extension expose other server extensions when launched directly?
     load_other_extensions = True
 
     # Local path to static files directory.
@@ -30,11 +30,11 @@ class SimpleServer(ExtensionApp):
 
     def initialize_handlers(self):
         self.handlers.extend([
-            (r'/simple_ext/params/(.+)$', ParameterHandler),
-            (r'/simple_ext/template', TemplateHandler),
-            (r'/simple_ext/page1/(.*)$', Page1Handler),
-            (r'/simple_ext/?', IndexHandler),
-            (r'/simple_ext/(.*)', ErrorHandler)
+            (r'/simple_ext1/params/(.+)$', ParameterHandler),
+            (r'/simple_ext1/template', TemplateHandler),
+            (r'/simple_ext1/page1/(.*)$', Page1Handler),
+            (r'/simple_ext1/?', IndexHandler),
+            (r'/simple_ext1/(.*)', ErrorHandler)
         ])
 
     def initialize_templates(self):
@@ -44,7 +44,7 @@ def initialize_templates(self):
             extensions=["jinja2.ext.i18n"],
             **jenv_opt
         )
-        template_settings = {"simple_ext_jinja2_env": env}
+        template_settings = {"simple_ext1_jinja2_env": env}
         self.settings.update(**template_settings)
 
     def initialize_settings(self):
@@ -54,4 +54,4 @@ def initialize_settings(self):
 # Main entry point
 #-----------------------------------------------------------------------------
 
-main = launch_new_instance = SimpleServer.launch_instance
+main = launch_new_instance = SimpleApp1.launch_instance
diff --git a/examples/simple/jupyter_simple_ext/handlers.py b/examples/simple/simple_ext1/handlers.py
similarity index 77%
rename from examples/simple/jupyter_simple_ext/handlers.py
rename to examples/simple/simple_ext1/handlers.py
index b5b92cf499..67f3c9daab 100644
--- a/examples/simple/jupyter_simple_ext/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -4,19 +4,19 @@ class TemplateHandler(ExtensionHandler):
 
     def get_template(self, name):
         """Return the jinja template object for a given name"""
-        return self.settings['simple_ext_jinja2_env'].get_template(name)
+        return self.settings['simple_ext1_jinja2_env'].get_template(name)
 
 class IndexHandler(TemplateHandler):
     
     def get(self):
         self.write(self.render_template("index.html"))
 
-class ParameterHandler(TemplateHandler):
+class ParameterHandler(ExtensionHandler):
     
     def get(self, matched_part=None, *args, **kwargs):
         var1 = self.get_argument('var1', default=None)
         components = [x for x in self.request.path.split("/") if x]
-        self.write('<h1>Hello Simple Server from Handler.</h1>')
+        self.write('<h1>Hello Simple App 1 from Handler.</h1>')
         self.write('<p>matched_part: {}</p>'.format(matched_part))
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
@@ -24,8 +24,8 @@ def get(self, matched_part=None, *args, **kwargs):
 class TemplateHandler(TemplateHandler):
     
     def get(self):
-        print(self.get_template('simple_ext.html'))
-        self.write(self.render_template('simple_ext.html'))
+        print(self.get_template('simple_ext1.html'))
+        self.write(self.render_template('simple_ext1.html'))
 
 class Page1Handler(TemplateHandler):
     
diff --git a/examples/simple/jupyter_simple_ext/static/bundle.js b/examples/simple/simple_ext1/static/bundle.js
similarity index 83%
rename from examples/simple/jupyter_simple_ext/static/bundle.js
rename to examples/simple/simple_ext1/static/bundle.js
index eedfa23390..f6b8f608a0 100644
--- a/examples/simple/jupyter_simple_ext/static/bundle.js
+++ b/examples/simple/simple_ext1/static/bundle.js
@@ -86,25 +86,25 @@
 /************************************************************************/
 /******/ ({
 
-/***/ "./jupyter_simple_ext/static/index.js":
-/*!********************************************!*\
-  !*** ./jupyter_simple_ext/static/index.js ***!
-  \********************************************/
+/***/ "./simple_ext1/static/index.js":
+/*!*************************************!*\
+  !*** ./simple_ext1/static/index.js ***!
+  \*************************************/
 /*! no static exports found */
 /***/ (function(module, exports) {
 
-eval("function main() {\n    let div = document.getElementById(\"mydiv\");\n    div.innerText = \"<h1>Hello from Typescript</h1>\";\n}\nwindow.addEventListener('load', main);\n\n\n//# sourceURL=webpack:///./jupyter_simple_ext/static/index.js?");
+eval("function main() {\n    let div = document.getElementById(\"mydiv\");\n    div.innerText = \"Hello from Typescript\";\n}\nwindow.addEventListener('load', main);\n\n\n//# sourceURL=webpack:///./simple_ext1/static/index.js?");
 
 /***/ }),
 
 /***/ 0:
-/*!**************************************************!*\
-  !*** multi ./jupyter_simple_ext/static/index.js ***!
-  \**************************************************/
+/*!*******************************************!*\
+  !*** multi ./simple_ext1/static/index.js ***!
+  \*******************************************/
 /*! no static exports found */
 /***/ (function(module, exports, __webpack_require__) {
 
-eval("module.exports = __webpack_require__(/*! ./jupyter_simple_ext/static/index.js */\"./jupyter_simple_ext/static/index.js\");\n\n\n//# sourceURL=webpack:///multi_./jupyter_simple_ext/static/index.js?");
+eval("module.exports = __webpack_require__(/*! ./simple_ext1/static/index.js */\"./simple_ext1/static/index.js\");\n\n\n//# sourceURL=webpack:///multi_./simple_ext1/static/index.js?");
 
 /***/ })
 
diff --git a/examples/simple/jupyter_simple_ext/static/favicon.ico b/examples/simple/simple_ext1/static/favicon.ico
similarity index 100%
rename from examples/simple/jupyter_simple_ext/static/favicon.ico
rename to examples/simple/simple_ext1/static/favicon.ico
diff --git a/examples/simple/jupyter_simple_ext/static/index.d.ts b/examples/simple/simple_ext1/static/index.d.ts
similarity index 100%
rename from examples/simple/jupyter_simple_ext/static/index.d.ts
rename to examples/simple/simple_ext1/static/index.d.ts
diff --git a/examples/simple/jupyter_simple_ext/static/index.js b/examples/simple/simple_ext1/static/index.js
similarity index 66%
rename from examples/simple/jupyter_simple_ext/static/index.js
rename to examples/simple/simple_ext1/static/index.js
index b18e39c21d..a7a67eed18 100644
--- a/examples/simple/jupyter_simple_ext/static/index.js
+++ b/examples/simple/simple_ext1/static/index.js
@@ -1,5 +1,5 @@
 function main() {
     let div = document.getElementById("mydiv");
-    div.innerText = "<h1>Hello from Typescript</h1>";
+    div.innerText = "Hello from Typescript";
 }
 window.addEventListener('load', main);
diff --git a/examples/simple/simple_ext1/static/test.html b/examples/simple/simple_ext1/static/test.html
new file mode 100644
index 0000000000..8c0bb51855
--- /dev/null
+++ b/examples/simple/simple_ext1/static/test.html
@@ -0,0 +1 @@
+<h1>Hello Simple App 1 from test HTML page.</h1>
diff --git a/examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo b/examples/simple/simple_ext1/static/tsconfig.tsbuildinfo
similarity index 98%
rename from examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo
rename to examples/simple/simple_ext1/static/tsconfig.tsbuildinfo
index bd022041a6..62d6680e8a 100644
--- a/examples/simple/jupyter_simple_ext/static/tsconfig.tsbuildinfo
+++ b/examples/simple/simple_ext1/static/tsconfig.tsbuildinfo
@@ -50,7 +50,7 @@
         "signature": "3e0a459888f32b42138d5a39f706ff2d55d500ab1031e0988b5568b0f67c2303"
       },
       "../../src/index.ts": {
-        "version": "03d69b24d41bd5bd41aecc996c31b8e908696cebbae569924ed26916a10924a9",
+        "version": "fd4f62325debd29128c1990caa4d546f2c48c21ea133fbcbb3e29f9fbef55e49",
         "signature": "ed4b087ea2a2e4a58647864cf512c7534210bfc2f9d236a2f9ed5245cf7a0896"
       }
     },
diff --git a/examples/simple/jupyter_simple_ext/templates/error.html b/examples/simple/simple_ext1/templates/error.html
similarity index 100%
rename from examples/simple/jupyter_simple_ext/templates/error.html
rename to examples/simple/simple_ext1/templates/error.html
diff --git a/examples/simple/jupyter_simple_ext/templates/index.html b/examples/simple/simple_ext1/templates/index.html
similarity index 100%
rename from examples/simple/jupyter_simple_ext/templates/index.html
rename to examples/simple/simple_ext1/templates/index.html
diff --git a/examples/simple/jupyter_simple_ext/templates/page.html b/examples/simple/simple_ext1/templates/page.html
similarity index 100%
rename from examples/simple/jupyter_simple_ext/templates/page.html
rename to examples/simple/simple_ext1/templates/page.html
diff --git a/examples/simple/jupyter_simple_ext/templates/page1.html b/examples/simple/simple_ext1/templates/page1.html
similarity index 100%
rename from examples/simple/jupyter_simple_ext/templates/page1.html
rename to examples/simple/simple_ext1/templates/page1.html
diff --git a/examples/simple/jupyter_simple_ext/templates/simple_ext.html b/examples/simple/simple_ext1/templates/simple_ext1.html
similarity index 100%
rename from examples/simple/jupyter_simple_ext/templates/simple_ext.html
rename to examples/simple/simple_ext1/templates/simple_ext1.html
diff --git a/examples/simple/simple_ext2/__init__.py b/examples/simple/simple_ext2/__init__.py
new file mode 100644
index 0000000000..f9d5935153
--- /dev/null
+++ b/examples/simple/simple_ext2/__init__.py
@@ -0,0 +1,8 @@
+from .application import SimpleApp2
+
+def _jupyter_server_extension_paths():
+    return [
+        {'module': 'simple_ext2'},
+    ]
+
+load_jupyter_server_extension = SimpleApp2.load_jupyter_server_extension
diff --git a/examples/simple/simple_ext2/application.py b/examples/simple/simple_ext2/application.py
new file mode 100644
index 0000000000..fd914237a6
--- /dev/null
+++ b/examples/simple/simple_ext2/application.py
@@ -0,0 +1,56 @@
+import os, jinja2
+from jupyter_server.extension.application import ExtensionApp
+from .handlers import ParameterHandler, TemplateHandler, IndexHandler, ErrorHandler
+
+DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
+DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
+
+print('--- {}'.format(DEFAULT_STATIC_FILES_PATH))
+
+class SimpleApp2(ExtensionApp):
+    
+    # The name of the extension
+    extension_name = "simple_ext2"
+
+    # Te url that your extension will serve its homepage.
+    default_url = '/simple_ext2'
+
+    # Should your extension expose other server extensions when launched directly?
+    load_other_extensions = False
+
+    # Local path to static files directory.
+    static_paths = [
+        DEFAULT_STATIC_FILES_PATH
+    ]
+
+    # Local path to templates directory.
+    template_paths = [
+        DEFAULT_TEMPLATE_FILES_PATH
+    ]
+
+    def initialize_handlers(self):
+        self.handlers.extend([
+            (r'/simple_ext2/params/(.+)$', ParameterHandler),
+            (r'/simple_ext2/template', TemplateHandler),
+            (r'/simple_ext2/?', IndexHandler),
+            (r'/simple_ext2/(.*)', ErrorHandler)
+        ])
+
+    def initialize_templates(self):
+        jenv_opt = {"autoescape": True}
+        env = jinja2.Environment(
+            loader=jinja2.FileSystemLoader(self.template_paths),
+            extensions=["jinja2.ext.i18n"],
+            **jenv_opt
+        )
+        template_settings = {"simple_ext2_jinja2_env": env}
+        self.settings.update(**template_settings)
+
+    def initialize_settings(self):
+        pass
+
+#-----------------------------------------------------------------------------
+# Main entry point
+#-----------------------------------------------------------------------------
+
+main = launch_new_instance = SimpleApp2.launch_instance
diff --git a/examples/simple/simple_ext2/handlers.py b/examples/simple/simple_ext2/handlers.py
new file mode 100644
index 0000000000..21fcec1732
--- /dev/null
+++ b/examples/simple/simple_ext2/handlers.py
@@ -0,0 +1,33 @@
+from jupyter_server.extension.handler import ExtensionHandler
+
+class TemplateHandler(ExtensionHandler):
+
+    def get_template(self, name):
+        """Return the jinja template object for a given name"""
+        return self.settings['simple_ext2_jinja2_env'].get_template(name)
+
+class IndexHandler(TemplateHandler):
+    
+    def get(self):
+        self.write(self.render_template("index.html"))
+
+class ParameterHandler(ExtensionHandler):
+    
+    def get(self, matched_part=None, *args, **kwargs):
+        var1 = self.get_argument('var1', default=None)
+        components = [x for x in self.request.path.split("/") if x]
+        self.write('<h1>Hello Simple App 2 from Handler.</h1>')
+        self.write('<p>matched_part: {}</p>'.format(matched_part))
+        self.write('<p>var1: {}</p>'.format(var1))
+        self.write('<p>components: {}</p>'.format(components))
+
+class TemplateHandler(TemplateHandler):
+    
+    def get(self):
+        print(self.get_template('simple_ext2.html'))
+        self.write(self.render_template('simple_ext2.html'))
+
+class ErrorHandler(TemplateHandler):
+    
+    def get(self, path):
+        self.write(self.render_template('error.html'))
diff --git a/examples/simple/simple_ext2/static/favicon.ico b/examples/simple/simple_ext2/static/favicon.ico
new file mode 100644
index 0000000000000000000000000000000000000000..2d1bcff7ca0ed6c77fdf1b016986f9137a43d31a
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a(pB%rsD1ysk;Z4#c@6$QfaHF(H1K~nNI6dc

literal 0
HcmV?d00001

diff --git a/examples/simple/simple_ext2/static/test.html b/examples/simple/simple_ext2/static/test.html
new file mode 100644
index 0000000000..1ac418d13d
--- /dev/null
+++ b/examples/simple/simple_ext2/static/test.html
@@ -0,0 +1 @@
+<h1>Hello Simple App 2 from test HTML page.</h1>
diff --git a/examples/simple/simple_ext2/templates/error.html b/examples/simple/simple_ext2/templates/error.html
new file mode 100644
index 0000000000..7426beb571
--- /dev/null
+++ b/examples/simple/simple_ext2/templates/error.html
@@ -0,0 +1,20 @@
+{% extends "page.html" %}
+
+{% block site %}
+
+<div class="error">
+    {% block h1_error %}
+    <h1>{{status_code}} : {{status_message}}</h1>
+    {% endblock h1_error %}
+
+    {% block error_detail %}
+    {% if message %}
+    <p>{% trans %}The error was:{% endtrans %}</p>
+    <div class="traceback-wrapper">
+    <pre class="traceback">{{message}}</pre>
+    </div>
+    {% endif %}
+    {% endblock error_detail %}
+</div>
+
+{% endblock %}
diff --git a/examples/simple/simple_ext2/templates/index.html b/examples/simple/simple_ext2/templates/index.html
new file mode 100644
index 0000000000..a42a0ab378
--- /dev/null
+++ b/examples/simple/simple_ext2/templates/index.html
@@ -0,0 +1 @@
+<h1>Hello Extension 2 from HTML Index Static Page</h1>
diff --git a/examples/simple/simple_ext2/templates/page.html b/examples/simple/simple_ext2/templates/page.html
new file mode 100644
index 0000000000..cf01c9a0b0
--- /dev/null
+++ b/examples/simple/simple_ext2/templates/page.html
@@ -0,0 +1,20 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>{% block title %}Jupyter Server 1{% endblock %}</title>
+    {% block favicon %}<link id="favicon" rel="shortcut icon" type="image/x-icon" href="{{ static_url("favicon.ico") }}">{% endblock %}
+    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    {% block meta %}
+    {% endblock %}
+</head>
+<body>
+  <div id="site">
+    {% block site %}
+    {% endblock site %}
+  </div>
+  {% block after_site %}
+  {% endblock after_site %}
+</body>
+</html>
diff --git a/examples/simple/simple_ext2/templates/simple_ext2.html b/examples/simple/simple_ext2/templates/simple_ext2.html
new file mode 100644
index 0000000000..0c7df48e9a
--- /dev/null
+++ b/examples/simple/simple_ext2/templates/simple_ext2.html
@@ -0,0 +1 @@
+<h1>Hello Extension 2 from Simple HTML Static Page</h1>
diff --git a/examples/simple/webpack.config.js b/examples/simple/webpack.config.js
index f39d5e004c..6016ce5260 100644
--- a/examples/simple/webpack.config.js
+++ b/examples/simple/webpack.config.js
@@ -1,7 +1,7 @@
 module.exports = {
-  entry: ['./jupyter_simple_ext/static/index.js'],
+  entry: ['./simple_ext1/static/index.js'],
   output: {
-    path: require('path').join(__dirname, 'jupyter_simple_ext', 'static'),
+    path: require('path').join(__dirname, 'simple_ext1', 'static'),
     filename: 'bundle.js'
   },
   mode: 'development'

From c3f9c286ef22e761d2a88c683da0fa7be00cbec6 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 12 Oct 2019 10:54:14 +0200
Subject: [PATCH 06/30] rm print static path

---
 examples/simple/simple_ext1/application.py | 2 --
 examples/simple/simple_ext2/application.py | 2 --
 2 files changed, 4 deletions(-)

diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 4a6c74965e..8e7512a399 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -5,8 +5,6 @@
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-print('--- {}'.format(DEFAULT_STATIC_FILES_PATH))
-
 class SimpleApp1(ExtensionApp):
     
     # The name of the extension
diff --git a/examples/simple/simple_ext2/application.py b/examples/simple/simple_ext2/application.py
index fd914237a6..f7cf0ad619 100644
--- a/examples/simple/simple_ext2/application.py
+++ b/examples/simple/simple_ext2/application.py
@@ -5,8 +5,6 @@
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-print('--- {}'.format(DEFAULT_STATIC_FILES_PATH))
-
 class SimpleApp2(ExtensionApp):
     
     # The name of the extension

From 08c126689d7fdb10e3b15fc0c4cd5b16fe094ef0 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Mon, 14 Oct 2019 08:56:09 +0200
Subject: [PATCH 07/30] mention
 https://github.com/markellekelly/jupyter-server-example in the README

---
 examples/simple/README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 766869b98e..0f8d9e23b4 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -2,14 +2,14 @@
 
 This folder contains an example of 2 simple extensions on top of Jupyter Server.
 
-OPTIONAL (compiled js is provided) If you want to build the typescript code, you need npm installed.
+OPTIONAL If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifcat in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
 
 ```bash
 make install-ts
 make build-ts
 ```
 
-You need python3 to build and run the extensions.
+You need `python3` to build and run the server extensions.
 
 ```bash
 conda create -y -n jext python=3.7

From 7aa92631a2c3a678c862b8e8414cbfa1e80e28c1 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Mon, 14 Oct 2019 09:15:39 +0200
Subject: [PATCH 08/30] add default redirect

---
 examples/simple/README.md                  | 30 ++++++++++++----------
 examples/simple/simple_ext1/application.py |  3 ++-
 examples/simple/simple_ext1/handlers.py    |  4 +++
 3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 0f8d9e23b4..e08d16e52d 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -2,12 +2,7 @@
 
 This folder contains an example of 2 simple extensions on top of Jupyter Server.
 
-OPTIONAL If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifcat in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
-
-```bash
-make install-ts
-make build-ts
-```
+## Install
 
 You need `python3` to build and run the server extensions.
 
@@ -17,12 +12,21 @@ conda activate jext
 make build
 ```
 
+**OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifcat in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
+
+```bash
+make install-ts
+make build-ts
+```
+
+## Start Extension 1 and Extension 2
+
 ```bash
 # Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
 make start1+2
 ```
 
-Optionally, you can copy `simple_ext.json` configuration to your env `etc` folder and start only App 1.
+Optionally, you can copy `simple_ext.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
 
 ```bash
 make uninstall
@@ -32,10 +36,10 @@ cp -r ./etc $(dirname $(which jupyter))/..
 make start1
 ```
 
-Render default Server content in your browser.
+Now you can render Server content in your browser.
 
 ```bash
-# Default server page.
+# Default server page should redirect to `/static/simple_ext1/favicon.ico`.
 open http://localhost:8888
 ```
 
@@ -66,6 +70,8 @@ open http://localhost:8888/static/simple_ext2/test.html
 open http://localhost:8888/simple_ext2/params/test?var1=foo
 ```
 
+## Start only Extension 2
+
 Now stop the server and start again with only Extension 2.
 
 ```bash
@@ -73,8 +79,4 @@ Now stop the server and start again with only Extension 2.
 make start2
 ```
 
-Try with the above links to check that only Extension 2 is responding.
-
-## TODO
-
-+ Automatic redirect on the default home page.
+Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an error).
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 8e7512a399..727056b506 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,6 +1,6 @@
 import os, jinja2
 from jupyter_server.extension.application import ExtensionApp
-from .handlers import ParameterHandler, TemplateHandler, Page1Handler, IndexHandler, ErrorHandler
+from .handlers import RedirectHandler, ParameterHandler, TemplateHandler, Page1Handler, IndexHandler, ErrorHandler
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
@@ -28,6 +28,7 @@ class SimpleApp1(ExtensionApp):
 
     def initialize_handlers(self):
         self.handlers.extend([
+            (r'/', RedirectHandler),
             (r'/simple_ext1/params/(.+)$', ParameterHandler),
             (r'/simple_ext1/template', TemplateHandler),
             (r'/simple_ext1/page1/(.*)$', Page1Handler),
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index 67f3c9daab..ad64c9df31 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -6,6 +6,10 @@ def get_template(self, name):
         """Return the jinja template object for a given name"""
         return self.settings['simple_ext1_jinja2_env'].get_template(name)
 
+class RedirectHandler(ExtensionHandler):
+    def get(self):
+        self.redirect("/static/simple_ext1/favicon.ico")
+
 class IndexHandler(TemplateHandler):
     
     def get(self):

From f6b8d479862752b264d367a1c1a1ea2cc80547ad Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Mon, 14 Oct 2019 21:37:09 +0200
Subject: [PATCH 09/30] migrate make to README + split simple_ext.json

---
 examples/simple/Makefile                      | 28 -------------------
 examples/simple/README.md                     | 20 ++++++-------
 .../jupyter_server_config.d/simple_ext1.json  |  7 +++++
 .../{simple_ext.json => simple_ext2.json}     |  1 -
 4 files changed, 17 insertions(+), 39 deletions(-)
 delete mode 100644 examples/simple/Makefile
 create mode 100644 examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext1.json
 rename examples/simple/etc/jupyter/jupyter_server_config.d/{simple_ext.json => simple_ext2.json} (75%)

diff --git a/examples/simple/Makefile b/examples/simple/Makefile
deleted file mode 100644
index b7324ebfd0..0000000000
--- a/examples/simple/Makefile
+++ /dev/null
@@ -1,28 +0,0 @@
-.PHONY: clean build install uninstall
-
-clean:
-	npm clean
-
-install-ts:
-	npm install
-	
-build-ts:
-	npm run build
-
-build:
-	pip install -e .
-
-install:
-	python setup.py install
-
-uninstall:
-	pip uninstall -y simple_ext
-
-start1+2:
-	jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
-
-start1:
-	jupyter simple-ext1
-
-start2:
-	jupyter simple-ext2
diff --git a/examples/simple/README.md b/examples/simple/README.md
index e08d16e52d..f373d84db5 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -9,31 +9,31 @@ You need `python3` to build and run the server extensions.
 ```bash
 conda create -y -n jext python=3.7
 conda activate jext
-make build
+pip install -e .
 ```
 
-**OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifcat in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
+**OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifact in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
 
 ```bash
-make install-ts
-make build-ts
+npm install
+npm run build
 ```
 
 ## Start Extension 1 and Extension 2
 
 ```bash
 # Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
-make start1+2
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
 ```
 
-Optionally, you can copy `simple_ext.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
+Optionally, you can copy `simple_ext1.json` and `simple_ext2.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
 
 ```bash
-make uninstall
-make install
+pip uninstall -y simple_ext
+python setup.py install
 cp -r ./etc $(dirname $(which jupyter))/..
 # Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
-make start1
+jupyter simple-ext1
 ```
 
 Now you can render Server content in your browser.
@@ -76,7 +76,7 @@ Now stop the server and start again with only Extension 2.
 
 ```bash
 # Start the jupyter server extension simple_ext2, it will NOT load simple_ext1 because of load_other_extensions = False.
-make start2
+jupyter simple-ext2
 ```
 
 Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an error).
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext1.json b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext1.json
new file mode 100644
index 0000000000..42e7565113
--- /dev/null
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext1.json
@@ -0,0 +1,7 @@
+{
+    "ServerApp": {
+        "jpserver_extensions": {
+            "simple_ext1": true
+        }
+    }
+}
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext2.json
similarity index 75%
rename from examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
rename to examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext2.json
index b3e2f07b59..8104acace1 100644
--- a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext.json
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext2.json
@@ -1,7 +1,6 @@
 {
     "ServerApp": {
         "jpserver_extensions": {
-            "simple_ext1": true,
             "simple_ext2": true
         }
     }

From beff8056208d1004163907c8f9cb500fde53e5ee Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Wed, 16 Oct 2019 07:59:06 +0200
Subject: [PATCH 10/30] relax jupyter_server version

---
 examples/simple/setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index a2e78122df..87ea4963ba 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -28,7 +28,7 @@ def add_data_files(path):
     packages = find_packages(),
     python_requires = '>=3.5',
     install_requires = [
-        'jupyter_server==0.1.1',
+        'jupyter_server',
         'jinja2',
     ],
     tests_requires = [

From d92fb550d9f0bd5aa0b69bb676de5a584500c0be Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Wed, 16 Oct 2019 08:00:47 +0200
Subject: [PATCH 11/30] add -f src

---
 examples/simple/src/index.ts      |  6 ++++++
 examples/simple/src/tsconfig.json | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 examples/simple/src/index.ts
 create mode 100644 examples/simple/src/tsconfig.json

diff --git a/examples/simple/src/index.ts b/examples/simple/src/index.ts
new file mode 100644
index 0000000000..3137216e29
--- /dev/null
+++ b/examples/simple/src/index.ts
@@ -0,0 +1,6 @@
+function main() {
+  let div = document.getElementById("mydiv");
+  div.innerText = "Hello from Typescript";
+}
+
+window.addEventListener('load', main);
diff --git a/examples/simple/src/tsconfig.json b/examples/simple/src/tsconfig.json
new file mode 100644
index 0000000000..711f9c1afc
--- /dev/null
+++ b/examples/simple/src/tsconfig.json
@@ -0,0 +1,21 @@
+    
+{
+  "compilerOptions": {
+    "outDir": "../simple_ext1/static",
+    "allowSyntheticDefaultImports": true,
+    "composite": true,
+    "declaration": true,
+    "noImplicitAny": true,
+    "noEmitOnError": true,
+    "noUnusedLocals": true,
+    "esModuleInterop": true,
+    "preserveWatchOutput": true,
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "target": "es2015",
+    "lib": ["dom", "es2015"],
+    "jsx": "react",
+    "types": []
+  },
+  "include": ["*"]
+}

From 7181ebbd762775674ea2dde12a2e8e3ff5d6fb14 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 19 Oct 2019 09:03:23 +0200
Subject: [PATCH 12/30] refactor handlers and add a TODO fix default URL

---
 examples/simple/README.md                     | 18 +++++++----
 examples/simple/simple_ext1/application.py    | 11 +++----
 examples/simple/simple_ext1/handlers.py       | 31 ++++++++-----------
 examples/simple/simple_ext1/static/home.html  |  1 +
 .../simple/simple_ext1/templates/error.html   |  1 +
 .../templates/{page1.html => simple1.html}    |  4 +--
 .../simple_ext1/templates/simple_ext1.html    | 21 -------------
 .../templates/{index.html => typescript.html} |  0
 examples/simple/simple_ext2/handlers.py       | 28 ++++++++---------
 9 files changed, 48 insertions(+), 67 deletions(-)
 create mode 100644 examples/simple/simple_ext1/static/home.html
 rename examples/simple/simple_ext1/templates/{page1.html => simple1.html} (85%)
 delete mode 100644 examples/simple/simple_ext1/templates/simple_ext1.html
 rename examples/simple/simple_ext1/templates/{index.html => typescript.html} (100%)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index f373d84db5..584b435780 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -44,21 +44,27 @@ open http://localhost:8888
 ```
 
 Render Extension 1 Server content in your browser.
-
+x
 ```bash
-# Favicon static content.
-open http://localhost:8888/static/simple_ext1/favicon.ico
+# Jupyter Server Home Page
+open http://localhost:8888/
+# TODO Fix Default URL.
+# Home page as defined by default_url = '/template1/home'.
+open http://localhost:8888/simple_ext1/
 # HTML static page.
 open http://localhost:8888/static/simple_ext1/test.html
 # Content from Handlers.
 open http://localhost:8888/simple_ext1/params/test?var1=foo
 # Content from Template.
-open http://localhost:8888/simple_ext1/page1/test
+open http://localhost:8888/simple_ext1/template1/test
 # Content from Template with Typescript.
-open http://localhost:8888/simple_ext1
-open http://localhost:8888/simple_ext1/template
+open http://localhost:8888/simple_ext1/typescript
 # Error content.
 open http://localhost:8888/simple_ext1/nope
+# Redirect.
+open http://localhost:8888/simple_ext1/redirect
+# Favicon static content.
+open http://localhost:8888/static/simple_ext1/favicon.ico
 ```
 
 Render Extension 2 Server content in your browser.
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 727056b506..a843a99548 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,6 +1,6 @@
 import os, jinja2
 from jupyter_server.extension.application import ExtensionApp
-from .handlers import RedirectHandler, ParameterHandler, TemplateHandler, Page1Handler, IndexHandler, ErrorHandler
+from .handlers import RedirectHandler, ParameterHandler, TemplateHandler, TypescriptHandler, ErrorHandler
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
@@ -11,7 +11,7 @@ class SimpleApp1(ExtensionApp):
     extension_name = "simple_ext1"
 
     # Te url that your extension will serve its homepage.
-    default_url = '/simple_ext1'
+    default_url = '/template/home'
 
     # Should your extension expose other server extensions when launched directly?
     load_other_extensions = True
@@ -28,11 +28,10 @@ class SimpleApp1(ExtensionApp):
 
     def initialize_handlers(self):
         self.handlers.extend([
-            (r'/', RedirectHandler),
             (r'/simple_ext1/params/(.+)$', ParameterHandler),
-            (r'/simple_ext1/template', TemplateHandler),
-            (r'/simple_ext1/page1/(.*)$', Page1Handler),
-            (r'/simple_ext1/?', IndexHandler),
+            (r'/simple_ext1/template1/(.*)$', TemplateHandler),
+            (r'/simple_ext1/redirect', RedirectHandler),
+            (r'/simple_ext1/typescript/?', TypescriptHandler),
             (r'/simple_ext1/(.*)', ErrorHandler)
         ])
 
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index ad64c9df31..3abd642595 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -1,20 +1,9 @@
 from jupyter_server.extension.handler import ExtensionHandler
 
-class TemplateHandler(ExtensionHandler):
-
-    def get_template(self, name):
-        """Return the jinja template object for a given name"""
-        return self.settings['simple_ext1_jinja2_env'].get_template(name)
-
 class RedirectHandler(ExtensionHandler):
     def get(self):
         self.redirect("/static/simple_ext1/favicon.ico")
 
-class IndexHandler(TemplateHandler):
-    
-    def get(self):
-        self.write(self.render_template("index.html"))
-
 class ParameterHandler(ExtensionHandler):
     
     def get(self, matched_part=None, *args, **kwargs):
@@ -25,18 +14,24 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class TemplateHandler(TemplateHandler):
+class BaseTemplateHandler(ExtensionHandler):
+
+    def get_template(self, path):
+        """Return the jinja template object for a given name"""
+        return self.settings['simple_ext1_jinja2_env'].get_template(path)
+
+class TypescriptHandler(BaseTemplateHandler):
     
     def get(self):
-        print(self.get_template('simple_ext1.html'))
-        self.write(self.render_template('simple_ext1.html'))
+        self.write(self.render_template("typescript.html"))
 
-class Page1Handler(TemplateHandler):
+class TemplateHandler(BaseTemplateHandler):
     
     def get(self, path):
-        self.write(self.render_template('page1.html', text=path))
+#        print(self.get_template('simple1.html'))
+        self.write(self.render_template('simple1.html', path=path))
 
-class ErrorHandler(TemplateHandler):
+class ErrorHandler(BaseTemplateHandler):
     
     def get(self, path):
-        self.write(self.render_template('error.html'))
+        self.write(self.render_template('error.html', path=path))
diff --git a/examples/simple/simple_ext1/static/home.html b/examples/simple/simple_ext1/static/home.html
new file mode 100644
index 0000000000..27fffd9e37
--- /dev/null
+++ b/examples/simple/simple_ext1/static/home.html
@@ -0,0 +1 @@
+<h1>Welcome to Simple App 1 Home Page.</h1>
diff --git a/examples/simple/simple_ext1/templates/error.html b/examples/simple/simple_ext1/templates/error.html
index 7426beb571..1379574a58 100644
--- a/examples/simple/simple_ext1/templates/error.html
+++ b/examples/simple/simple_ext1/templates/error.html
@@ -4,6 +4,7 @@
 
 <div class="error">
     {% block h1_error %}
+    <h1>Error Page</h1>
     <h1>{{status_code}} : {{status_message}}</h1>
     {% endblock h1_error %}
 
diff --git a/examples/simple/simple_ext1/templates/page1.html b/examples/simple/simple_ext1/templates/simple1.html
similarity index 85%
rename from examples/simple/simple_ext1/templates/page1.html
rename to examples/simple/simple_ext1/templates/simple1.html
index 7fba4842ae..95d8403ce0 100644
--- a/examples/simple/simple_ext1/templates/page1.html
+++ b/examples/simple/simple_ext1/templates/simple1.html
@@ -14,6 +14,6 @@
   </script>
 </head>
 <body>
-  <h1>Hello from Page 1 Template.</h1>
-  <p>Path: {{text}}</p>
+  <h1>Hello Simple App 1 from Template.</h1>
+  <p>Path: {{path}}</p>
 </body>
diff --git a/examples/simple/simple_ext1/templates/simple_ext1.html b/examples/simple/simple_ext1/templates/simple_ext1.html
deleted file mode 100644
index e825cf31cb..0000000000
--- a/examples/simple/simple_ext1/templates/simple_ext1.html
+++ /dev/null
@@ -1,21 +0,0 @@
-<!doctype html>
-<html lang="en">
-<head>
-  <meta charset="utf-8">
-  <script src="{{static_url('bundle.js')}}" type="text/javascript" charset="utf-8"></script>
-  <script type="text/javascript">
-    /* Remove token from URL. */
-    (function () {
-      var parsedUrl = new URL(window.location.href);
-      if (parsedUrl.searchParams.get('token')) {
-        parsedUrl.searchParams.delete('token');
-        window.history.replaceState({ }, '', parsedUrl.href);
-      }
-    })();
-  </script>
-</head>
-<body>
-  <div id="mydiv">
-  <h1>Hello world! </h1>
-  </div>
-</body>
diff --git a/examples/simple/simple_ext1/templates/index.html b/examples/simple/simple_ext1/templates/typescript.html
similarity index 100%
rename from examples/simple/simple_ext1/templates/index.html
rename to examples/simple/simple_ext1/templates/typescript.html
diff --git a/examples/simple/simple_ext2/handlers.py b/examples/simple/simple_ext2/handlers.py
index 21fcec1732..07249393a9 100644
--- a/examples/simple/simple_ext2/handlers.py
+++ b/examples/simple/simple_ext2/handlers.py
@@ -1,16 +1,5 @@
 from jupyter_server.extension.handler import ExtensionHandler
 
-class TemplateHandler(ExtensionHandler):
-
-    def get_template(self, name):
-        """Return the jinja template object for a given name"""
-        return self.settings['simple_ext2_jinja2_env'].get_template(name)
-
-class IndexHandler(TemplateHandler):
-    
-    def get(self):
-        self.write(self.render_template("index.html"))
-
 class ParameterHandler(ExtensionHandler):
     
     def get(self, matched_part=None, *args, **kwargs):
@@ -21,13 +10,24 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class TemplateHandler(TemplateHandler):
+class BaseTemplateHandler(ExtensionHandler):
+
+    def get_template(self, name):
+        """Return the jinja template object for a given name"""
+        return self.settings['simple_ext2_jinja2_env'].get_template(name)
+
+class IndexHandler(BaseTemplateHandler):
     
     def get(self):
+        self.write(self.render_template("index.html"))
+
+class TemplateHandler(BaseTemplateHandler):
+    
+    def get(self, path):
         print(self.get_template('simple_ext2.html'))
-        self.write(self.render_template('simple_ext2.html'))
+        self.write(self.render_template('simple_ext2.html', path=path))
 
-class ErrorHandler(TemplateHandler):
+class ErrorHandler(BaseTemplateHandler):
     
     def get(self, path):
         self.write(self.render_template('error.html'))

From b5c371387a5e00bd52f8bbfda5db3a52b25e75ac Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Tue, 22 Oct 2019 11:13:28 +0200
Subject: [PATCH 13/30] be more precise on returned error

---
 examples/simple/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 584b435780..c5f3bfd0a0 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -85,4 +85,4 @@ Now stop the server and start again with only Extension 2.
 jupyter simple-ext2
 ```
 
-Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an error).
+Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an 404 error).

From ea0555afe5e478bce6811d844de1241ec4a5f3ce Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Wed, 30 Oct 2019 16:44:27 +0100
Subject: [PATCH 14/30] more examples related to settings and extension

---
 examples/simple/README.md                     | 74 ++++++++++++++-----
 .../jupyter_server_config.d/simple_ext11.json |  7 ++
 examples/simple/jupyter_server_config.py      | 11 +++
 examples/simple/setup.py                      |  3 +-
 examples/simple/simple_ext1/application.py    | 27 ++++---
 examples/simple/simple_ext1/handlers.py       | 22 ++++--
 examples/simple/simple_ext11/__init__.py      |  8 ++
 examples/simple/simple_ext11/application.py   | 35 +++++++++
 examples/simple/simple_ext2/application.py    |  2 +-
 examples/simple/simple_ext2/handlers.py       |  5 --
 10 files changed, 154 insertions(+), 40 deletions(-)
 create mode 100644 examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext11.json
 create mode 100644 examples/simple/jupyter_server_config.py
 create mode 100644 examples/simple/simple_ext11/__init__.py
 create mode 100644 examples/simple/simple_ext11/application.py

diff --git a/examples/simple/README.md b/examples/simple/README.md
index c5f3bfd0a0..d9287a0034 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -7,9 +7,9 @@ This folder contains an example of 2 simple extensions on top of Jupyter Server.
 You need `python3` to build and run the server extensions.
 
 ```bash
-conda create -y -n jext python=3.7
-conda activate jext
-pip install -e .
+conda create -y -n jext python=3.7 && \
+  conda activate jext && \
+  pip install -e .
 ```
 
 **OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifact in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
@@ -36,21 +36,14 @@ cp -r ./etc $(dirname $(which jupyter))/..
 jupyter simple-ext1
 ```
 
-Now you can render Server content in your browser.
+Now you can render Extension 1 Server content in your browser.
 
 ```bash
-# Default server page should redirect to `/static/simple_ext1/favicon.ico`.
-open http://localhost:8888
-```
-
-Render Extension 1 Server content in your browser.
-x
-```bash
-# Jupyter Server Home Page
+# Jupyter Server Home Page.
 open http://localhost:8888/
-# TODO Fix Default URL.
-# Home page as defined by default_url = '/template1/home'.
-open http://localhost:8888/simple_ext1/
+# TODO Fix Default URL, it does not show on startup.
+# Home page as defined by default_url = '/default'.
+open http://localhost:8888/simple_ext1/default
 # HTML static page.
 open http://localhost:8888/static/simple_ext1/test.html
 # Content from Handlers.
@@ -67,7 +60,7 @@ open http://localhost:8888/simple_ext1/redirect
 open http://localhost:8888/static/simple_ext1/favicon.ico
 ```
 
-Render Extension 2 Server content in your browser.
+You can also render Extension 2 Server content in your browser.
 
 ```bash
 # HTML static page.
@@ -76,8 +69,25 @@ open http://localhost:8888/static/simple_ext2/test.html
 open http://localhost:8888/simple_ext2/params/test?var1=foo
 ```
 
-## Start only Extension 2
+## Settings
+
+Start with additional settings.
+
+```bash
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}" --SimpleApp1.cli=OK
+```
+
+Check the log, it should return on startup something like the following base on the trait you have defined in the CLI and in the `jupyter_server_config.py`.
 
+```
+[SimpleApp1] SimpleApp1.app OK
+[SimpleApp1] SimpleApp1.file OK
+[SimpleApp1] SimpleApp1.cli OK
+[SimpleApp1] Complete Settings {'simple_ext1_config': {}, 'simple_ext1_template_paths': ['/home/datalayer/repos/jupyter-server/examples/simple/simple_ext1/templates'], 'simple_ext1_jinja2_env': <jinja2.environment.Environment object at 0x105ed7438>, 'log_function': <function log_request at 0x105e2d950>, 'base_url': '/', 'default_url': '/', 'template_path': ['/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server', '/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/templates'], 'static_path': ['/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/static'], 'static_custom_path': ['/home/datalayer/.jupyter/custom', '/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/static/custom'], 'static_handler_class': <class 'jupyter_server.base.handlers.FileFindHandler'>, 'static_url_prefix': ...
+```
+
+## Start only Extension 2
+`
 Now stop the server and start again with only Extension 2.
 
 ```bash
@@ -86,3 +96,33 @@ jupyter simple-ext2
 ```
 
 Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an 404 error).
+
+## Extension 11 extending Extension 1
+
+```bash
+jupyter simple-ext11
+# or...
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}"
+```
+
+```bash
+# Jupyter Server Home Page.
+open http://localhost:8888/
+# TODO Fix Default URL, it does not show on startup.
+# Home page as defined by default_url = '/default'.
+open http://localhost:8888/simple_ext11/default
+# HTML static page.
+open http://localhost:8888/static/simple_ext11/test.html
+# Content from Handlers.
+open http://localhost:8888/simple_ext11/params/test?var1=foo
+# Content from Template.
+open http://localhost:8888/simple_ext11/template1/test
+# Content from Template with Typescript.
+open http://localhost:8888/simple_ext11/typescript
+# Error content.
+open http://localhost:8888/simple_ext11/nope
+# Redirect.
+open http://localhost:8888/simple_ext11/redirect
+# Favicon static content.
+open http://localhost:8888/static/simple_ext11/favicon.ico
+```
diff --git a/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext11.json b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext11.json
new file mode 100644
index 0000000000..4f9cbbbfac
--- /dev/null
+++ b/examples/simple/etc/jupyter/jupyter_server_config.d/simple_ext11.json
@@ -0,0 +1,7 @@
+{
+    "ServerApp": {
+        "jpserver_extensions": {
+            "simple_ext11": true
+        }
+    }
+}
diff --git a/examples/simple/jupyter_server_config.py b/examples/simple/jupyter_server_config.py
new file mode 100644
index 0000000000..fd1ad65bbe
--- /dev/null
+++ b/examples/simple/jupyter_server_config.py
@@ -0,0 +1,11 @@
+# Configuration file for jupyter-server extensions.
+
+#------------------------------------------------------------------------------
+# Application(SingletonConfigurable) configuration
+#------------------------------------------------------------------------------
+
+## The date format used by logging formatters for %(asctime)s
+c.Application.log_datefmt = '%Y-%m-%d %H:%M:%S Simple_Extensions'
+
+c.SimpleApp1.file = 'OK'
+c.SimpleApp2.file = 'OK'
diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index 87ea4963ba..d20af9a90c 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -13,7 +13,7 @@ def add_data_files(path):
         for (dirpath, dirnames, filenames) in os.walk(path):
             if filenames:
                 data_files.append((dirpath, [os.path.join(dirpath, filename) for filename in filenames]))
-    # Add all the templates
+    # Add all static and templates folders.
     add_data_files('simple_ext1/static')
     add_data_files('simple_ext1/templates')
     add_data_files('simple_ext2/static')
@@ -40,6 +40,7 @@ def add_data_files(path):
     entry_points = {
         'console_scripts': [
              'jupyter-simple-ext1 = simple_ext1.application:main',
+             'jupyter-simple-ext11 = simple_ext11.application:main',
              'jupyter-simple-ext2 = simple_ext2.application:main'
         ]
     },
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index a843a99548..209e5f7b0a 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,17 +1,18 @@
 import os, jinja2
 from jupyter_server.extension.application import ExtensionApp
-from .handlers import RedirectHandler, ParameterHandler, TemplateHandler, TypescriptHandler, ErrorHandler
+from .handlers import (DefaultHandler, RedirectHandler, ParameterHandler, 
+  TemplateHandler, TypescriptHandler, ErrorHandler)
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
 class SimpleApp1(ExtensionApp):
     
-    # The name of the extension
+    # The name of the extension.
     extension_name = "simple_ext1"
 
     # Te url that your extension will serve its homepage.
-    default_url = '/template/home'
+    default_url = '/default'
 
     # Should your extension expose other server extensions when launched directly?
     load_other_extensions = True
@@ -28,11 +29,12 @@ class SimpleApp1(ExtensionApp):
 
     def initialize_handlers(self):
         self.handlers.extend([
-            (r'/simple_ext1/params/(.+)$', ParameterHandler),
-            (r'/simple_ext1/template1/(.*)$', TemplateHandler),
-            (r'/simple_ext1/redirect', RedirectHandler),
-            (r'/simple_ext1/typescript/?', TypescriptHandler),
-            (r'/simple_ext1/(.*)', ErrorHandler)
+            (r'/{}/default'.format(self.extension_name), DefaultHandler),
+            (r'/{}/params/(.+)$'.format(self.extension_name), ParameterHandler),
+            (r'/{}/template1/(.*)$'.format(self.extension_name), TemplateHandler),
+            (r'/{}/redirect'.format(self.extension_name), RedirectHandler),
+            (r'/{}/typescript/?'.format(self.extension_name), TypescriptHandler),
+            (r'/{}/(.*)', ErrorHandler)
         ])
 
     def initialize_templates(self):
@@ -45,8 +47,15 @@ def initialize_templates(self):
         template_settings = {"simple_ext1_jinja2_env": env}
         self.settings.update(**template_settings)
 
+    def get_conf(self, key):
+        return self.settings.get('config').get('SimpleApp1').get(key, None)
+
     def initialize_settings(self):
-        pass
+        self.settings.get('config').get('SimpleApp1').update({'app': 'OK'})
+        self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
+        self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
+        self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
+        self.log.info('Complete Settings {}'.format(self.settings))
 
 #-----------------------------------------------------------------------------
 # Main entry point
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index 3abd642595..ffe1752c96 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -1,11 +1,23 @@
 from jupyter_server.extension.handler import ExtensionHandler
 
+class DefaultHandler(ExtensionHandler):
+    def get(self):
+        # The ExtensionApp’s config object.
+        self.log.info("Settings: {}".format(self.settings))
+        self.log.info("Config: {}".format(self.config))
+        # TODO The ServerApp’s config object.
+        # self.log.info(self.server_config)
+        # The name of the extension to which this handler is linked.
+        self.log.info("Extension Name: {}".format(self.extension_name))
+        # A method for getting the url to static files (prefixed with /static/<extension_name>).
+        self.log.info("Static URL for /:".format(self.static_url(path='/')))
+        self.write('<h1>Hello Simple 1 - I am the default...</h1>')
+
 class RedirectHandler(ExtensionHandler):
     def get(self):
-        self.redirect("/static/simple_ext1/favicon.ico")
+        self.redirect("/static/{}/favicon.ico".format(self.extension_name))
 
-class ParameterHandler(ExtensionHandler):
-    
+class ParameterHandler(ExtensionHandler):    
     def get(self, matched_part=None, *args, **kwargs):
         var1 = self.get_argument('var1', default=None)
         components = [x for x in self.request.path.split("/") if x]
@@ -15,23 +27,19 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>components: {}</p>'.format(components))
 
 class BaseTemplateHandler(ExtensionHandler):
-
     def get_template(self, path):
         """Return the jinja template object for a given name"""
         return self.settings['simple_ext1_jinja2_env'].get_template(path)
 
 class TypescriptHandler(BaseTemplateHandler):
-    
     def get(self):
         self.write(self.render_template("typescript.html"))
 
 class TemplateHandler(BaseTemplateHandler):
-    
     def get(self, path):
 #        print(self.get_template('simple1.html'))
         self.write(self.render_template('simple1.html', path=path))
 
 class ErrorHandler(BaseTemplateHandler):
-    
     def get(self, path):
         self.write(self.render_template('error.html', path=path))
diff --git a/examples/simple/simple_ext11/__init__.py b/examples/simple/simple_ext11/__init__.py
new file mode 100644
index 0000000000..cf3068ed96
--- /dev/null
+++ b/examples/simple/simple_ext11/__init__.py
@@ -0,0 +1,8 @@
+from .application import SimpleApp1
+
+def _jupyter_server_extension_paths():
+    return [
+        {'module': 'simple_ext1'}
+    ]
+
+load_jupyter_server_extension = SimpleApp1.load_jupyter_server_extension
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
new file mode 100644
index 0000000000..b15a659889
--- /dev/null
+++ b/examples/simple/simple_ext11/application.py
@@ -0,0 +1,35 @@
+import os
+from simple_ext1.application import SimpleApp1
+
+DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/static")
+DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/templates")
+
+class SimpleApp11(SimpleApp1):
+    
+    # The name of the extension.
+    extension_name = "simple_ext11"
+
+    # Local path to static files directory.
+    static_paths = [
+        DEFAULT_STATIC_FILES_PATH
+    ]
+
+    # Local path to templates directory.
+    template_paths = [
+        DEFAULT_TEMPLATE_FILES_PATH
+    ]
+
+    def initialize_handlers(self):
+        super().initialize_handlers()
+
+    def initialize_templates(self):
+        super().initialize_templates()
+
+    def initialize_settings(self):
+        super().initialize_templates()
+
+#-----------------------------------------------------------------------------
+# Main entry point
+#-----------------------------------------------------------------------------
+
+main = launch_new_instance = SimpleApp11.launch_instance
diff --git a/examples/simple/simple_ext2/application.py b/examples/simple/simple_ext2/application.py
index f7cf0ad619..5aca43b9fb 100644
--- a/examples/simple/simple_ext2/application.py
+++ b/examples/simple/simple_ext2/application.py
@@ -7,7 +7,7 @@
 
 class SimpleApp2(ExtensionApp):
     
-    # The name of the extension
+    # The name of the extension.
     extension_name = "simple_ext2"
 
     # Te url that your extension will serve its homepage.
diff --git a/examples/simple/simple_ext2/handlers.py b/examples/simple/simple_ext2/handlers.py
index 07249393a9..490333ced6 100644
--- a/examples/simple/simple_ext2/handlers.py
+++ b/examples/simple/simple_ext2/handlers.py
@@ -1,7 +1,6 @@
 from jupyter_server.extension.handler import ExtensionHandler
 
 class ParameterHandler(ExtensionHandler):
-    
     def get(self, matched_part=None, *args, **kwargs):
         var1 = self.get_argument('var1', default=None)
         components = [x for x in self.request.path.split("/") if x]
@@ -11,23 +10,19 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>components: {}</p>'.format(components))
 
 class BaseTemplateHandler(ExtensionHandler):
-
     def get_template(self, name):
         """Return the jinja template object for a given name"""
         return self.settings['simple_ext2_jinja2_env'].get_template(name)
 
 class IndexHandler(BaseTemplateHandler):
-    
     def get(self):
         self.write(self.render_template("index.html"))
 
 class TemplateHandler(BaseTemplateHandler):
-    
     def get(self, path):
         print(self.get_template('simple_ext2.html'))
         self.write(self.render_template('simple_ext2.html', path=path))
 
 class ErrorHandler(BaseTemplateHandler):
-    
     def get(self, path):
         self.write(self.render_template('error.html'))

From e9d1a6951e1f81cff83651413aca6b5a7cbf44f3 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 31 Oct 2019 17:22:56 +0100
Subject: [PATCH 15/30] extension 11 has flags and aliases

---
 examples/simple/README.md                   | 10 ++++++++--
 examples/simple/simple_ext11/application.py | 22 +++++++++++++++------
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index d9287a0034..bbf6877e3f 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -99,12 +99,18 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 ## Extension 11 extending Extension 1
 
+`Extension 11` extends `Extension 1`. It also implemnets additional flags and aliases.
+
+The `--hello` flag will log on startup `Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True`.
+
 ```bash
-jupyter simple-ext11
+jupyter simple-ext11 --hello
 # or...
-jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}"
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}" --hello
 ```
 
+Ensure the following URLs give respond correctly.
+
 ```bash
 # Jupyter Server Home Page.
 open http://localhost:8888/
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index b15a659889..3c76cc78f8 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -1,10 +1,18 @@
 import os
 from simple_ext1.application import SimpleApp1
+from jupyter_server.serverapp import aliases, flags
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/templates")
 
 class SimpleApp11(SimpleApp1):
+    flags['hello']=(
+        {'SimpleApp11' : {'hello' : True}},
+        "Say hello on startup."
+    )
+    aliases.update({
+        'notebook-dir': 'ServerApp.notebook_dir',
+    })
     
     # The name of the extension.
     extension_name = "simple_ext11"
@@ -19,14 +27,16 @@ class SimpleApp11(SimpleApp1):
         DEFAULT_TEMPLATE_FILES_PATH
     ]
 
-    def initialize_handlers(self):
-        super().initialize_handlers()
-
-    def initialize_templates(self):
-        super().initialize_templates()
+    def get_conf(self, key):
+        simple_app_11 = self.settings.get('config').get('SimpleApp11')
+        if simple_app_11:
+            return simple_app_11.get(key, None)
+        return None
 
     def initialize_settings(self):
-        super().initialize_templates()
+        if self.get_conf('hello') == True:
+            self.log.info('Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True')
+        super().initialize_settings()
 
 #-----------------------------------------------------------------------------
 # Main entry point

From b5f57669450db43e33f8b40d2216ca422974db47 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 31 Oct 2019 18:10:43 +0100
Subject: [PATCH 16/30] default_url

---
 examples/simple/simple_ext1/application.py  | 2 +-
 examples/simple/simple_ext11/application.py | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 209e5f7b0a..7c9bdd70f5 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -12,7 +12,7 @@ class SimpleApp1(ExtensionApp):
     extension_name = "simple_ext1"
 
     # Te url that your extension will serve its homepage.
-    default_url = '/default'
+    default_url = '/simple_ext1/default'
 
     # Should your extension expose other server extensions when launched directly?
     load_other_extensions = True
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index 3c76cc78f8..2e219f000b 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -17,6 +17,9 @@ class SimpleApp11(SimpleApp1):
     # The name of the extension.
     extension_name = "simple_ext11"
 
+    # Te url that your extension will serve its homepage.
+    default_url = '/simple_ext11/default'
+
     # Local path to static files directory.
     static_paths = [
         DEFAULT_STATIC_FILES_PATH

From 0a215bd6a6991e418b385718ee97833101adf6c9 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Tue, 5 Nov 2019 16:33:05 +0100
Subject: [PATCH 17/30] more settings example based on flags and file configs

---
 examples/simple/README.md                   | 25 +++++++-----
 examples/simple/jupyter_server_config.py    |  2 +
 examples/simple/simple_ext1/application.py  |  2 +
 examples/simple/simple_ext11/application.py | 44 +++++++++++++++++----
 4 files changed, 55 insertions(+), 18 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index bbf6877e3f..979d072665 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -7,8 +7,8 @@ This folder contains an example of 2 simple extensions on top of Jupyter Server.
 You need `python3` to build and run the server extensions.
 
 ```bash
-conda create -y -n jext python=3.7 && \
-  conda activate jext && \
+conda create -y -n jupyter_server_example python=3.7 && \
+  conda activate jupyter_server_example && \
   pip install -e .
 ```
 
@@ -33,10 +33,11 @@ pip uninstall -y simple_ext
 python setup.py install
 cp -r ./etc $(dirname $(which jupyter))/..
 # Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
+# When you invoke with the entrypoint, the default url will be opened in your browser.
 jupyter simple-ext1
 ```
 
-Now you can render Extension 1 Server content in your browser.
+Now you can render `Extension 1` Server content in your browser.
 
 ```bash
 # Jupyter Server Home Page.
@@ -60,7 +61,7 @@ open http://localhost:8888/simple_ext1/redirect
 open http://localhost:8888/static/simple_ext1/favicon.ico
 ```
 
-You can also render Extension 2 Server content in your browser.
+You can also render `Extension 2` Server content in your browser.
 
 ```bash
 # HTML static page.
@@ -71,7 +72,7 @@ open http://localhost:8888/simple_ext2/params/test?var1=foo
 
 ## Settings
 
-Start with additional settings.
+Stop any running server (with CTRL+C) and start with additional settings on the command line.
 
 ```bash
 jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}" --SimpleApp1.cli=OK
@@ -83,12 +84,12 @@ Check the log, it should return on startup something like the following base on
 [SimpleApp1] SimpleApp1.app OK
 [SimpleApp1] SimpleApp1.file OK
 [SimpleApp1] SimpleApp1.cli OK
-[SimpleApp1] Complete Settings {'simple_ext1_config': {}, 'simple_ext1_template_paths': ['/home/datalayer/repos/jupyter-server/examples/simple/simple_ext1/templates'], 'simple_ext1_jinja2_env': <jinja2.environment.Environment object at 0x105ed7438>, 'log_function': <function log_request at 0x105e2d950>, 'base_url': '/', 'default_url': '/', 'template_path': ['/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server', '/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/templates'], 'static_path': ['/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/static'], 'static_custom_path': ['/home/datalayer/.jupyter/custom', '/opt/datalayer/opt/miniconda3/envs/datalayer/lib/python3.7/site-packages/jupyter_server/static/custom'], 'static_handler_class': <class 'jupyter_server.base.handlers.FileFindHandler'>, 'static_url_prefix': ...
+[SimpleApp1] Complete Settings {'simple_ext1_config': {}, 'simple_ext1_template_paths': ['/home/datalayer/repos/jupyter-server/examples/simple/simple_ext1/templates'], 'simple_ext1_jinja2_env': <jinja2.environment.Environment object at 0x105ed7438>, 'log_function': <function log_request at 0x105e2d950>, 'base_url': '/', 'default_url': '/', 'template_path': ...
 ```
 
 ## Start only Extension 2
-`
-Now stop the server and start again with only Extension 2.
+
+Now stop agin the server and start with only `Extension 2`.
 
 ```bash
 # Start the jupyter server extension simple_ext2, it will NOT load simple_ext1 because of load_other_extensions = False.
@@ -103,10 +104,14 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 The `--hello` flag will log on startup `Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True`.
 
+The `--simple11-dir` alias will set `SimpleExt11.simple11_dir` settings.
+
+Stop any running server and then start the simple-ext11.
+
 ```bash
-jupyter simple-ext11 --hello
+jupyter simple-ext11 --hello --simple11-dir any_folder
 # or...
-jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}" --hello
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}" --hello --simple11-dir any_folder
 ```
 
 Ensure the following URLs give respond correctly.
diff --git a/examples/simple/jupyter_server_config.py b/examples/simple/jupyter_server_config.py
index fd1ad65bbe..b761706893 100644
--- a/examples/simple/jupyter_server_config.py
+++ b/examples/simple/jupyter_server_config.py
@@ -9,3 +9,5 @@
 
 c.SimpleApp1.file = 'OK'
 c.SimpleApp2.file = 'OK'
+
+c.SimpleApp11.ignore_js = True
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 7c9bdd70f5..a37adc63c1 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -56,6 +56,8 @@ def initialize_settings(self):
         self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
         self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
         self.log.info('Complete Settings {}'.format(self.settings))
+        # TODO Check this setting/config handling... Updating does not look to be fine here...
+        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp1'))
 
 #-----------------------------------------------------------------------------
 # Main entry point
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index 2e219f000b..a007a64b80 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -1,17 +1,17 @@
 import os
 from simple_ext1.application import SimpleApp1
 from jupyter_server.serverapp import aliases, flags
+from traitlets import Bool, Unicode, observe
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "./../simple_ext1/templates")
 
 class SimpleApp11(SimpleApp1):
     flags['hello']=(
-        {'SimpleApp11' : {'hello' : True}},
-        "Say hello on startup."
+        { 'SimpleApp11' : {'hello' : False} }, "Say hello on startup."
     )
     aliases.update({
-        'notebook-dir': 'ServerApp.notebook_dir',
+        'simple11-dir': 'SimpleApp11.simple11_dir',
     })
     
     # The name of the extension.
@@ -30,15 +30,43 @@ class SimpleApp11(SimpleApp1):
         DEFAULT_TEMPLATE_FILES_PATH
     ]
 
+    simple11_dir = Unicode('',
+        config=True,
+        help='Simple directory'
+    )
+
+    hello = Bool(False,
+        config=True,
+        help='Say hello', 
+    )
+
+    ignore_js = Bool(False,
+        config=True,
+        help='Ignore Javascript', 
+    )
+
+    @observe('ignore_js')
+    def _update_ignore_js(self, change):
+        """TODO The observe does not work"""
+        self.log.info('ignore_js has just changed: {}'.format(change))
+
+    @property
+    def simple11_dir_formatted(self):
+        return "/" + self.simple11_dir
+
     def get_conf(self, key):
-        simple_app_11 = self.settings.get('config').get('SimpleApp11')
-        if simple_app_11:
-            return simple_app_11.get(key, None)
-        return None
+        return self.settings.get('config').get('SimpleApp11').get(key, None)
 
     def initialize_settings(self):
+        self.log.info('SimpleApp11.hello: {}'.format(self.get_conf('hello')))
+        self.log.info('hello: {}'.format(self.hello))
         if self.get_conf('hello') == True:
-            self.log.info('Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True')
+            self.log.info("Hello Simple11 - You have provided the --hello flag or defined 'c.SimpleApp1.hello == True' in jupyter_server_config.py")
+        self.log.info('SimpleApp11.simple11_dir: {}'.format(self.get_conf('simple11_dir')))
+        self.log.info('SimpleApp11.ignore_js: {}'.format(self.get_conf('ignore_js')))
+        self.log.info('ignore_js: {}'.format(self.ignore_js))
+        # TODO Check this setting/config handling... Updating does not look to be fine here...
+        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp11'))
         super().initialize_settings()
 
 #-----------------------------------------------------------------------------

From b462e9d04cfed0e7d69c6da3cc84e43a953429b7 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 7 Nov 2019 18:39:32 +0100
Subject: [PATCH 18/30] add a link to static home

---
 examples/simple/README.md                  | 2 +-
 examples/simple/simple_ext1/application.py | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 979d072665..d86bc4939c 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -42,10 +42,10 @@ Now you can render `Extension 1` Server content in your browser.
 ```bash
 # Jupyter Server Home Page.
 open http://localhost:8888/
-# TODO Fix Default URL, it does not show on startup.
 # Home page as defined by default_url = '/default'.
 open http://localhost:8888/simple_ext1/default
 # HTML static page.
+open http://localhost:8888/static/simple_ext1/home.html
 open http://localhost:8888/static/simple_ext1/test.html
 # Content from Handlers.
 open http://localhost:8888/simple_ext1/params/test?var1=foo
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index a37adc63c1..4b2f08fd0a 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,7 +1,7 @@
 import os, jinja2
 from jupyter_server.extension.application import ExtensionApp
-from .handlers import (DefaultHandler, RedirectHandler, ParameterHandler, 
-  TemplateHandler, TypescriptHandler, ErrorHandler)
+from .handlers import (DefaultHandler, RedirectHandler, 
+  ParameterHandler, TemplateHandler, TypescriptHandler, ErrorHandler)
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")

From 81e99d8270f7ab2ba5f409af9528b60d3c80ed56 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 16 Nov 2019 11:19:13 +0100
Subject: [PATCH 19/30] more details on SimpleExt11 configs

---
 examples/simple/README.md                  | 44 ++++++++++++++++++++--
 examples/simple/simple_ext1/application.py |  4 +-
 2 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index d86bc4939c..bf3cbd3528 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -100,11 +100,49 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 ## Extension 11 extending Extension 1
 
-`Extension 11` extends `Extension 1`. It also implemnets additional flags and aliases.
+`Extension 11` extends `Extension 1`.
 
-The `--hello` flag will log on startup `Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True`.
+It brings a few more configs. Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
 
-The `--simple11-dir` alias will set `SimpleExt11.simple11_dir` settings.
+The generated configuration should contains the following.
+
+```bash
+...
+#  Can be used to override templates from notebook.templates.
+#c.ExtensionApp.template_paths = []
+
+#------------------------------------------------------------------------------
+# SimpleApp1(ExtensionApp) configuration
+#------------------------------------------------------------------------------
+
+#------------------------------------------------------------------------------
+# SimpleApp11(SimpleApp1) configuration
+#------------------------------------------------------------------------------
+
+## Say hello
+#c.SimpleApp11.hello = False
+
+## Ignore Javascript
+#c.SimpleApp11.ignore_js = False
+
+## Simple directory
+#c.SimpleApp11.simple11_dir = ''
+
+#------------------------------------------------------------------------------
+# ServerApp(JupyterApp) configuration
+#------------------------------------------------------------------------------
+
+## Set the Access-Control-Allow-Credentials: true header
+#c.ServerApp.allow_credentials = False
+...
+```
+
+The `hello`, `ignoare_js` and `simple11_dir` are traits defined on the SimpleApp11 class.
+
+It also implements additional flags and aliases for these traits.
+
++ The `--hello` flag will log on startup `Hello Simple11 - You have provided the --hello flag or defined a c.SimpleApp1.hello == True`.
++ The `--simple11-dir` alias will set `SimpleExt11.simple11_dir` settings.
 
 Stop any running server and then start the simple-ext11.
 
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 4b2f08fd0a..4159fcf14f 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -51,13 +51,13 @@ def get_conf(self, key):
         return self.settings.get('config').get('SimpleApp1').get(key, None)
 
     def initialize_settings(self):
-        self.settings.get('config').get('SimpleApp1').update({'app': 'OK'})
         self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
         self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
         self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
         self.log.info('Complete Settings {}'.format(self.settings))
         # TODO Check this setting/config handling... Updating does not look to be fine here...
-        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp1'))
+#        self.settings.get('config').get(self.extension_name).update({'app': 'OK'})
+#        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp1'))
 
 #-----------------------------------------------------------------------------
 # Main entry point

From edc21fc9f75a954c2934db9039a1246a89a94f05 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 16 Nov 2019 16:16:20 +0100
Subject: [PATCH 20/30] simple_app11: hello flag set True to hell config

---
 examples/simple/simple_ext11/application.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index a007a64b80..c0ae7c8fd9 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -8,7 +8,7 @@
 
 class SimpleApp11(SimpleApp1):
     flags['hello']=(
-        { 'SimpleApp11' : {'hello' : False} }, "Say hello on startup."
+        { 'SimpleApp11' : {'hello' : True} }, "Say hello on startup."
     )
     aliases.update({
         'simple11-dir': 'SimpleApp11.simple11_dir',

From ae3d27c84a06adfd306eec8374f824db82c626a1 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Fri, 22 Nov 2019 06:01:37 +0100
Subject: [PATCH 21/30] add the correct json in setup.py

---
 examples/simple/setup.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index d20af9a90c..5d06d98bdf 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -7,7 +7,9 @@ def get_data_files():
     """Get the data files for the package.
     """
     data_files = [
-        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext.json']),
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext1.json']),
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext2.json']),
+        ('etc/jupyter/jupyter_server_config.d', ['etc/jupyter/jupyter_server_config.d/simple_ext11.json']),
     ]
     def add_data_files(path):
         for (dirpath, dirnames, filenames) in os.walk(path):
@@ -36,6 +38,7 @@ def add_data_files(path):
         'pytest-cov',
         'pylint',
     ],
+    include_package_data=True,
     data_files = get_data_files(),
     entry_points = {
         'console_scripts': [

From f65c74e25ae73860078add435b43bd6b5c3f3c96 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Tue, 3 Dec 2019 15:18:49 -0600
Subject: [PATCH 22/30] more work on settings

---
 examples/simple/README.md                   |  6 ++--
 examples/simple/jupyter_server_config.py    |  5 ----
 examples/simple/setup.py                    |  2 +-
 examples/simple/simple_ext1/application.py  | 32 +++++++++++++++++----
 examples/simple/simple_ext1/handlers.py     |  9 +++---
 examples/simple/simple_ext11/application.py | 12 ++++----
 6 files changed, 39 insertions(+), 27 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index bf3cbd3528..ec22f511c0 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -29,7 +29,7 @@ jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ex
 Optionally, you can copy `simple_ext1.json` and `simple_ext2.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
 
 ```bash
-pip uninstall -y simple_ext
+pip uninstall -y jupyter_simple_ext
 python setup.py install
 cp -r ./etc $(dirname $(which jupyter))/..
 # Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
@@ -100,9 +100,9 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 ## Extension 11 extending Extension 1
 
-`Extension 11` extends `Extension 1`.
+`Extension 11` extends `Extension 1` and brings a few more configs.
 
-It brings a few more configs. Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
+Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
 
 The generated configuration should contains the following.
 
diff --git a/examples/simple/jupyter_server_config.py b/examples/simple/jupyter_server_config.py
index b761706893..d7cc88f800 100644
--- a/examples/simple/jupyter_server_config.py
+++ b/examples/simple/jupyter_server_config.py
@@ -6,8 +6,3 @@
 
 ## The date format used by logging formatters for %(asctime)s
 c.Application.log_datefmt = '%Y-%m-%d %H:%M:%S Simple_Extensions'
-
-c.SimpleApp1.file = 'OK'
-c.SimpleApp2.file = 'OK'
-
-c.SimpleApp11.ignore_js = True
diff --git a/examples/simple/setup.py b/examples/simple/setup.py
index 5d06d98bdf..061cc3a792 100755
--- a/examples/simple/setup.py
+++ b/examples/simple/setup.py
@@ -23,7 +23,7 @@ def add_data_files(path):
     return data_files
 
 setuptools.setup(
-    name = 'simple_ext',
+    name = 'jupyter_simple_ext',
     version = VERSION,
     description = 'Jupyter Simple Extension',
     long_description = open('README.md').read(),
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 4159fcf14f..5c2a1c72e9 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,4 +1,5 @@
 import os, jinja2
+from traitlets import Unicode
 from jupyter_server.extension.application import ExtensionApp
 from .handlers import (DefaultHandler, RedirectHandler, 
   ParameterHandler, TemplateHandler, TypescriptHandler, ErrorHandler)
@@ -27,6 +28,21 @@ class SimpleApp1(ExtensionApp):
         DEFAULT_TEMPLATE_FILES_PATH
     ]
 
+    file = Unicode('',
+        config=True,
+        help='File path'
+    )
+
+    app = Unicode('',
+        config=True,
+        help='File path'
+    )
+
+    cli = Unicode('',
+        config=True,
+        help='File path'
+    )
+
     def initialize_handlers(self):
         self.handlers.extend([
             (r'/{}/default'.format(self.extension_name), DefaultHandler),
@@ -48,14 +64,18 @@ def initialize_templates(self):
         self.settings.update(**template_settings)
 
     def get_conf(self, key):
-        return self.settings.get('config').get('SimpleApp1').get(key, None)
+        c = self.settings.get('config').get(type(self).__name__)
+        if c:
+            return c.get(key, None)
+        else:
+            return None
 
     def initialize_settings(self):
-        self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
-        self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
-        self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
-        self.log.info('Complete Settings {}'.format(self.settings))
-        # TODO Check this setting/config handling... Updating does not look to be fine here...
+        self.log.info('333 {}'.format(self.config))
+#        self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
+#        self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
+#        self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
+#        self.log.info('Complete Settings {}'.format(self.settings))
 #        self.settings.get('config').get(self.extension_name).update({'app': 'OK'})
 #        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp1'))
 
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index ffe1752c96..9062e5e64e 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -3,14 +3,13 @@
 class DefaultHandler(ExtensionHandler):
     def get(self):
         # The ExtensionApp’s config object.
-        self.log.info("Settings: {}".format(self.settings))
-        self.log.info("Config: {}".format(self.config))
-        # TODO The ServerApp’s config object.
+#        self.log.info("Settings in {} Default Handler: {}".format(self.extension_name, self.settings))
+        self.log.info("Config in {} Default Handler: {}".format(self.extension_name, self.config))
         # self.log.info(self.server_config)
         # The name of the extension to which this handler is linked.
-        self.log.info("Extension Name: {}".format(self.extension_name))
+        self.log.info("Extension Name in {} Default Handler: {}".format(self.extension_name, self.extension_name))
         # A method for getting the url to static files (prefixed with /static/<extension_name>).
-        self.log.info("Static URL for /:".format(self.static_url(path='/')))
+        self.log.info("Static URL for / in simple_ext1 Default Handler:".format(self.static_url(path='/')))
         self.write('<h1>Hello Simple 1 - I am the default...</h1>')
 
 class RedirectHandler(ExtensionHandler):
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index c0ae7c8fd9..ddeeadad1e 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -54,20 +54,18 @@ def _update_ignore_js(self, change):
     def simple11_dir_formatted(self):
         return "/" + self.simple11_dir
 
-    def get_conf(self, key):
-        return self.settings.get('config').get('SimpleApp11').get(key, None)
-
     def initialize_settings(self):
-        self.log.info('SimpleApp11.hello: {}'.format(self.get_conf('hello')))
+        self.log.info('SimpleApp11.hello: {}'.format(super().get_conf('hello')))
         self.log.info('hello: {}'.format(self.hello))
         if self.get_conf('hello') == True:
             self.log.info("Hello Simple11 - You have provided the --hello flag or defined 'c.SimpleApp1.hello == True' in jupyter_server_config.py")
         self.log.info('SimpleApp11.simple11_dir: {}'.format(self.get_conf('simple11_dir')))
         self.log.info('SimpleApp11.ignore_js: {}'.format(self.get_conf('ignore_js')))
         self.log.info('ignore_js: {}'.format(self.ignore_js))
-        # TODO Check this setting/config handling... Updating does not look to be fine here...
-        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp11'))
-        super().initialize_settings()
+        c = self.settings.get('config').get(type(self).__name__)
+        if c:
+            self.settings["{}_config".format(self.extension_name)].update(**c)
+#        super().initialize_settings()
 
 #-----------------------------------------------------------------------------
 # Main entry point

From 25504c8f19e5cd6b619009b2610cd7540c32aa1f Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Tue, 3 Dec 2019 15:19:57 -0600
Subject: [PATCH 23/30] add configuration files

---
 examples/simple/jupyter_simple_ext11_config.py | 1 +
 examples/simple/jupyter_simple_ext1_config.py  | 3 +++
 examples/simple/jupyter_simple_ext2_config.py  | 1 +
 3 files changed, 5 insertions(+)
 create mode 100644 examples/simple/jupyter_simple_ext11_config.py
 create mode 100644 examples/simple/jupyter_simple_ext1_config.py
 create mode 100644 examples/simple/jupyter_simple_ext2_config.py

diff --git a/examples/simple/jupyter_simple_ext11_config.py b/examples/simple/jupyter_simple_ext11_config.py
new file mode 100644
index 0000000000..d2baa1360a
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext11_config.py
@@ -0,0 +1 @@
+c.SimpleApp11.ignore_js = True
diff --git a/examples/simple/jupyter_simple_ext1_config.py b/examples/simple/jupyter_simple_ext1_config.py
new file mode 100644
index 0000000000..dc7cd842ec
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext1_config.py
@@ -0,0 +1,3 @@
+c.SimpleApp1.app = 'an app'
+c.SimpleApp1.cli = 'a cli'
+c.SimpleApp1.file = 'a file'
diff --git a/examples/simple/jupyter_simple_ext2_config.py b/examples/simple/jupyter_simple_ext2_config.py
new file mode 100644
index 0000000000..36b3b6751c
--- /dev/null
+++ b/examples/simple/jupyter_simple_ext2_config.py
@@ -0,0 +1 @@
+c.SimpleApp2.file = 'OK'

From 1b58d296ef0b4dfb4090aa738b662cca191d62b6 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Wed, 4 Dec 2019 11:01:54 -0600
Subject: [PATCH 24/30] comment logs

---
 examples/simple/simple_ext1/application.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 5c2a1c72e9..24b6b7f104 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -71,7 +71,7 @@ def get_conf(self, key):
             return None
 
     def initialize_settings(self):
-        self.log.info('333 {}'.format(self.config))
+        self.log.info('Config {}'.format(self.config))
 #        self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
 #        self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
 #        self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))

From ff341a1841577687f7724707bd32222036b155a2 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Wed, 4 Dec 2019 11:49:17 -0600
Subject: [PATCH 25/30] update readme

---
 examples/simple/README.md | 64 ++++++++++++++++++++++++---------------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index ec22f511c0..a8e7f83b72 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -1,13 +1,15 @@
 # Jupyter Server Simple Extension Example
 
-This folder contains an example of 2 simple extensions on top of Jupyter Server.
+This folder contains example of simple extensions on top of Jupyter Server and review configuration aspects.
 
 ## Install
 
 You need `python3` to build and run the server extensions.
 
 ```bash
-conda create -y -n jupyter_server_example python=3.7 && \
+git clone https://github.com/jupyter/jupyter_server && \
+  cd examples/simple && \
+  conda create -y -n jupyter_server_example python=3.7 && \
   conda activate jupyter_server_example && \
   pip install -e .
 ```
@@ -15,26 +17,15 @@ conda create -y -n jupyter_server_example python=3.7 && \
 **OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifact in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
 
 ```bash
-npm install
-npm run build
+npm install && \
+  npm run build
 ```
 
-## Start Extension 1 and Extension 2
+## Start Extension 1
 
 ```bash
-# Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
-jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
-```
-
-Optionally, you can copy `simple_ext1.json` and `simple_ext2.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
-
-```bash
-pip uninstall -y jupyter_simple_ext
-python setup.py install
-cp -r ./etc $(dirname $(which jupyter))/..
-# Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
-# When you invoke with the entrypoint, the default url will be opened in your browser.
-jupyter simple-ext1
+# Start the jupyter server activating simple_ext1 extension.
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True}"
 ```
 
 Now you can render `Extension 1` Server content in your browser.
@@ -61,6 +52,15 @@ open http://localhost:8888/simple_ext1/redirect
 open http://localhost:8888/static/simple_ext1/favicon.ico
 ```
 
+## Start Extension 2
+
+The following command starts both `simple_ext1` and `simple_ext2` extensions.
+
+```bash
+# Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
+jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
+```
+
 You can also render `Extension 2` Server content in your browser.
 
 ```bash
@@ -70,12 +70,29 @@ open http://localhost:8888/static/simple_ext2/test.html
 open http://localhost:8888/simple_ext2/params/test?var1=foo
 ```
 
-## Settings
+## Start with Entrypoints
+
+Optionally, you can copy `simple_ext1.json` and `simple_ext2.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
+
+```bash
+pip uninstall -y jupyter_simple_ext && \
+  python setup.py install && \
+  cp -r ./etc $(dirname $(which jupyter))/..
+# Start the jupyter server extension simple_ext1, it will also load simple_ext2 because of load_other_extensions = True..
+# When you invoke with the entrypoint, the default url will be opened in your browser.
+jupyter simple-ext1
+```
+
+## Configuration
+
+Stop any running server (with `CTRL+C`) and start with additional configuration on the command line.
 
-Stop any running server (with CTRL+C) and start with additional settings on the command line.
+The provided settings via CLI will override the configuration that reside in the files (`jupyter_simple_ext1_config.py`...)
 
 ```bash
-jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}" --SimpleApp1.cli=OK
+jupyter server \ 
+  --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}" \
+  --SimpleApp1.cli=OK
 ```
 
 Check the log, it should return on startup something like the following base on the trait you have defined in the CLI and in the `jupyter_server_config.py`.
@@ -84,7 +101,6 @@ Check the log, it should return on startup something like the following base on
 [SimpleApp1] SimpleApp1.app OK
 [SimpleApp1] SimpleApp1.file OK
 [SimpleApp1] SimpleApp1.cli OK
-[SimpleApp1] Complete Settings {'simple_ext1_config': {}, 'simple_ext1_template_paths': ['/home/datalayer/repos/jupyter-server/examples/simple/simple_ext1/templates'], 'simple_ext1_jinja2_env': <jinja2.environment.Environment object at 0x105ed7438>, 'log_function': <function log_request at 0x105e2d950>, 'base_url': '/', 'default_url': '/', 'template_path': ...
 ```
 
 ## Start only Extension 2
@@ -137,7 +153,7 @@ The generated configuration should contains the following.
 ...
 ```
 
-The `hello`, `ignoare_js` and `simple11_dir` are traits defined on the SimpleApp11 class.
+The `hello`, `ignore_js` and `simple11_dir` are traits defined on the SimpleApp11 class.
 
 It also implements additional flags and aliases for these traits.
 
@@ -152,7 +168,7 @@ jupyter simple-ext11 --hello --simple11-dir any_folder
 jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}" --hello --simple11-dir any_folder
 ```
 
-Ensure the following URLs give respond correctly.
+Ensure the following URLs respond correctly.
 
 ```bash
 # Jupyter Server Home Page.

From 43b744758b7f06ace2eb933cd3d5f57ac1cf9fbc Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 9 Jan 2020 14:38:33 +0100
Subject: [PATCH 26/30] rename configs

---
 examples/simple/README.md                     | 80 ++++++++-----------
 examples/simple/jupyter_server_config.py      |  2 +-
 examples/simple/jupyter_simple_ext1_config.py |  6 +-
 examples/simple/jupyter_simple_ext2_config.py |  2 +-
 examples/simple/simple_ext1/application.py    | 35 ++------
 examples/simple/simple_ext1/handlers.py       |  9 +--
 examples/simple/simple_ext11/application.py   | 10 +--
 examples/simple/simple_ext2/application.py    | 18 ++---
 8 files changed, 58 insertions(+), 104 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index a8e7f83b72..5733f54fea 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -7,6 +7,7 @@ This folder contains example of simple extensions on top of Jupyter Server and r
 You need `python3` to build and run the server extensions.
 
 ```bash
+# Clone, create a conda env and install from source.
 git clone https://github.com/jupyter/jupyter_server && \
   cd examples/simple && \
   conda create -y -n jupyter_server_example python=3.7 && \
@@ -14,14 +15,30 @@ git clone https://github.com/jupyter/jupyter_server && \
   pip install -e .
 ```
 
-**OPTIONAL** If you want to build the Typescript code, you need `npm` on your local env. Compiled javascript is provided as artifact in this repository, so this Typescript build step is optional. The Typescript source and configuration has been taken from https://github.com/markellekelly/jupyter-server-example.
+**OPTIONAL** If you want to build the Typescript code, you need [npm](https://www.npmjs.com) on your local environement. Compiled javascript is provided as artifact in this repository, so this Typescript build step is optional. The Typescript source and configuration have been taken from https://github.com/markellekelly/jupyter-server-example.
 
 ```bash
 npm install && \
   npm run build
 ```
 
-## Start Extension 1
+## No Extension
+
+Ensure Jupyter Server is starting without any extension enabled.
+
+```bash
+# Run this command from a shell.
+jupyter server
+```
+
+Browse the default home page, it should show a white page in your browser with the following content: `A Jupyter Server is running.`
+
+```bash
+# Jupyter Server default Home Page.
+open http://localhost:8888
+```
+
+## Extension 1
 
 ```bash
 # Start the jupyter server activating simple_ext1 extension.
@@ -31,8 +48,6 @@ jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True}"
 Now you can render `Extension 1` Server content in your browser.
 
 ```bash
-# Jupyter Server Home Page.
-open http://localhost:8888/
 # Home page as defined by default_url = '/default'.
 open http://localhost:8888/simple_ext1/default
 # HTML static page.
@@ -52,16 +67,16 @@ open http://localhost:8888/simple_ext1/redirect
 open http://localhost:8888/static/simple_ext1/favicon.ico
 ```
 
-## Start Extension 2
+## Extension 1 and Extension 2
 
-The following command starts both `simple_ext1` and `simple_ext2` extensions.
+The following command starts both the `simple_ext1` and `simple_ext2` extensions.
 
 ```bash
 # Start the jupyter server, it will load both simple_ext1 and simple_ext2 based on the provided trait.
 jupyter server --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}"
 ```
 
-You can also render `Extension 2` Server content in your browser.
+Check that the previous `Extension 1` content is still available ant that you can also render `Extension 2` Server content in your browser.
 
 ```bash
 # HTML static page.
@@ -70,7 +85,7 @@ open http://localhost:8888/static/simple_ext2/test.html
 open http://localhost:8888/simple_ext2/params/test?var1=foo
 ```
 
-## Start with Entrypoints
+## Work with Entrypoints
 
 Optionally, you can copy `simple_ext1.json` and `simple_ext2.json` configuration to your env `etc` folder and start only Extension 1, which will also start Extension 2.
 
@@ -90,20 +105,20 @@ Stop any running server (with `CTRL+C`) and start with additional configuration
 The provided settings via CLI will override the configuration that reside in the files (`jupyter_simple_ext1_config.py`...)
 
 ```bash
-jupyter server \ 
-  --ServerApp.jpserver_extensions="{'simple_ext1': True, 'simple_ext2': True}" \
-  --SimpleApp1.cli=OK
+jupyter simple-ext1 --SimpleApp1.configA "ConfigA from command line"
 ```
 
-Check the log, it should return on startup something like the following base on the trait you have defined in the CLI and in the `jupyter_server_config.py`.
+Check the log, it should return on startup something like the following base on the trait you have defined in the CLI and in the `jupyter_simple_ext1_config.py`.
 
 ```
-[SimpleApp1] SimpleApp1.app OK
-[SimpleApp1] SimpleApp1.file OK
-[SimpleApp1] SimpleApp1.cli OK
+[SimpleApp1] Config {'SimpleApp1': {'configA': 'ConfigA from file', 'configB': 'ConfigB from file', 'configC': 'ConfigC from file'}}
+[SimpleApp1] Config {'SimpleApp1': {'configA': 'ConfigA from file', 'configB': 'ConfigB from file', 'configC': 'ConfigC from file'}}
+[SimpleApp2] WARNING | Config option `configD` not recognized by `SimpleApp2`.  Did you mean `config_file`?
+[SimpleApp2] Config {'SimpleApp2': {'configD': 'ConfigD from file'}}
+[SimpleApp1] Config {'SimpleApp1': {'configA': 'ConfigA from command line', 'configB': 'ConfigB from file', 'configC': 'ConfigC from file'}}
 ```
 
-## Start only Extension 2
+## Only Extension 2
 
 Now stop agin the server and start with only `Extension 2`.
 
@@ -114,43 +129,18 @@ jupyter simple-ext2
 
 Try with the above links to check that only Extension 2 is responding (Extension 1 URLs should give you an 404 error).
 
-## Extension 11 extending Extension 1
+## Extension 11 extends Extension 1
 
 `Extension 11` extends `Extension 1` and brings a few more configs.
 
 Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
 
+> --generate-config returns an execption `"The ExtensionApp has not ServerApp "`
+
 The generated configuration should contains the following.
 
 ```bash
-...
-#  Can be used to override templates from notebook.templates.
-#c.ExtensionApp.template_paths = []
-
-#------------------------------------------------------------------------------
-# SimpleApp1(ExtensionApp) configuration
-#------------------------------------------------------------------------------
-
-#------------------------------------------------------------------------------
-# SimpleApp11(SimpleApp1) configuration
-#------------------------------------------------------------------------------
-
-## Say hello
-#c.SimpleApp11.hello = False
-
-## Ignore Javascript
-#c.SimpleApp11.ignore_js = False
-
-## Simple directory
-#c.SimpleApp11.simple11_dir = ''
-
-#------------------------------------------------------------------------------
-# ServerApp(JupyterApp) configuration
-#------------------------------------------------------------------------------
-
-## Set the Access-Control-Allow-Credentials: true header
-#c.ServerApp.allow_credentials = False
-...
+TBD
 ```
 
 The `hello`, `ignore_js` and `simple11_dir` are traits defined on the SimpleApp11 class.
diff --git a/examples/simple/jupyter_server_config.py b/examples/simple/jupyter_server_config.py
index d7cc88f800..d8f9314192 100644
--- a/examples/simple/jupyter_server_config.py
+++ b/examples/simple/jupyter_server_config.py
@@ -5,4 +5,4 @@
 #------------------------------------------------------------------------------
 
 ## The date format used by logging formatters for %(asctime)s
-c.Application.log_datefmt = '%Y-%m-%d %H:%M:%S Simple_Extensions'
+c.Application.log_datefmt = '%Y-%m-%d %H:%M:%S Simple_Extensions_Example'
diff --git a/examples/simple/jupyter_simple_ext1_config.py b/examples/simple/jupyter_simple_ext1_config.py
index dc7cd842ec..bf4624a486 100644
--- a/examples/simple/jupyter_simple_ext1_config.py
+++ b/examples/simple/jupyter_simple_ext1_config.py
@@ -1,3 +1,3 @@
-c.SimpleApp1.app = 'an app'
-c.SimpleApp1.cli = 'a cli'
-c.SimpleApp1.file = 'a file'
+c.SimpleApp1.configA = 'ConfigA from file'
+c.SimpleApp1.configB = 'ConfigB from file'
+c.SimpleApp1.configC = 'ConfigC from file'
diff --git a/examples/simple/jupyter_simple_ext2_config.py b/examples/simple/jupyter_simple_ext2_config.py
index 36b3b6751c..6bdbc06089 100644
--- a/examples/simple/jupyter_simple_ext2_config.py
+++ b/examples/simple/jupyter_simple_ext2_config.py
@@ -1 +1 @@
-c.SimpleApp2.file = 'OK'
+c.SimpleApp2.configD = 'ConfigD from file'
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 24b6b7f104..83868c0651 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -28,19 +28,19 @@ class SimpleApp1(ExtensionApp):
         DEFAULT_TEMPLATE_FILES_PATH
     ]
 
-    file = Unicode('',
+    configA = Unicode('',
         config=True,
-        help='File path'
+        help='Config A example.'
     )
 
-    app = Unicode('',
+    configB = Unicode('',
         config=True,
-        help='File path'
+        help='Config B example.'
     )
 
-    cli = Unicode('',
+    configC = Unicode('',
         config=True,
-        help='File path'
+        help='Config C example.'
     )
 
     def initialize_handlers(self):
@@ -53,31 +53,8 @@ def initialize_handlers(self):
             (r'/{}/(.*)', ErrorHandler)
         ])
 
-    def initialize_templates(self):
-        jenv_opt = {"autoescape": True}
-        env = jinja2.Environment(
-            loader=jinja2.FileSystemLoader(self.template_paths),
-            extensions=["jinja2.ext.i18n"],
-            **jenv_opt
-        )
-        template_settings = {"simple_ext1_jinja2_env": env}
-        self.settings.update(**template_settings)
-
-    def get_conf(self, key):
-        c = self.settings.get('config').get(type(self).__name__)
-        if c:
-            return c.get(key, None)
-        else:
-            return None
-
     def initialize_settings(self):
         self.log.info('Config {}'.format(self.config))
-#        self.log.info('SimpleApp1.app {}'.format(self.get_conf('app')))
-#        self.log.info('SimpleApp1.file {}'.format(self.get_conf('file')))
-#        self.log.info('SimpleApp1.cli {}'.format(self.get_conf('cli')))
-#        self.log.info('Complete Settings {}'.format(self.settings))
-#        self.settings.get('config').get(self.extension_name).update({'app': 'OK'})
-#        self.settings["{}_config".format(self.extension_name)].update(**self.settings.get('config').get('SimpleApp1'))
 
 #-----------------------------------------------------------------------------
 # Main entry point
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index 9062e5e64e..5f21e0220a 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -2,15 +2,12 @@
 
 class DefaultHandler(ExtensionHandler):
     def get(self):
-        # The ExtensionApp’s config object.
-#        self.log.info("Settings in {} Default Handler: {}".format(self.extension_name, self.settings))
-        self.log.info("Config in {} Default Handler: {}".format(self.extension_name, self.config))
-        # self.log.info(self.server_config)
         # The name of the extension to which this handler is linked.
         self.log.info("Extension Name in {} Default Handler: {}".format(self.extension_name, self.extension_name))
         # A method for getting the url to static files (prefixed with /static/<extension_name>).
         self.log.info("Static URL for / in simple_ext1 Default Handler:".format(self.static_url(path='/')))
         self.write('<h1>Hello Simple 1 - I am the default...</h1>')
+        self.write('Config in {} Default Handler: {}'.format(self.extension_name, self.config))
 
 class RedirectHandler(ExtensionHandler):
     def get(self):
@@ -28,7 +25,7 @@ def get(self, matched_part=None, *args, **kwargs):
 class BaseTemplateHandler(ExtensionHandler):
     def get_template(self, path):
         """Return the jinja template object for a given name"""
-        return self.settings['simple_ext1_jinja2_env'].get_template(path)
+        return self.settings['{}_jinja2_env'.format(self.extension_name)].get_template(path)
 
 class TypescriptHandler(BaseTemplateHandler):
     def get(self):
@@ -36,7 +33,7 @@ def get(self):
 
 class TemplateHandler(BaseTemplateHandler):
     def get(self, path):
-#        print(self.get_template('simple1.html'))
+        """ Optionaly, you can print(self.get_template('simple1.html'))"""
         self.write(self.render_template('simple1.html', path=path))
 
 class ErrorHandler(BaseTemplateHandler):
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index ddeeadad1e..2c39cfe955 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -55,17 +55,11 @@ def simple11_dir_formatted(self):
         return "/" + self.simple11_dir
 
     def initialize_settings(self):
-        self.log.info('SimpleApp11.hello: {}'.format(super().get_conf('hello')))
         self.log.info('hello: {}'.format(self.hello))
-        if self.get_conf('hello') == True:
+        if self.config['hello'] == True:
             self.log.info("Hello Simple11 - You have provided the --hello flag or defined 'c.SimpleApp1.hello == True' in jupyter_server_config.py")
-        self.log.info('SimpleApp11.simple11_dir: {}'.format(self.get_conf('simple11_dir')))
-        self.log.info('SimpleApp11.ignore_js: {}'.format(self.get_conf('ignore_js')))
         self.log.info('ignore_js: {}'.format(self.ignore_js))
-        c = self.settings.get('config').get(type(self).__name__)
-        if c:
-            self.settings["{}_config".format(self.extension_name)].update(**c)
-#        super().initialize_settings()
+        super().initialize_settings()
 
 #-----------------------------------------------------------------------------
 # Main entry point
diff --git a/examples/simple/simple_ext2/application.py b/examples/simple/simple_ext2/application.py
index 5aca43b9fb..1f31b417af 100644
--- a/examples/simple/simple_ext2/application.py
+++ b/examples/simple/simple_ext2/application.py
@@ -1,4 +1,5 @@
 import os, jinja2
+from traitlets import Unicode
 from jupyter_server.extension.application import ExtensionApp
 from .handlers import ParameterHandler, TemplateHandler, IndexHandler, ErrorHandler
 
@@ -26,6 +27,11 @@ class SimpleApp2(ExtensionApp):
         DEFAULT_TEMPLATE_FILES_PATH
     ]
 
+    configD = Unicode('',
+        config=True,
+        help='Config D example.'
+    )
+
     def initialize_handlers(self):
         self.handlers.extend([
             (r'/simple_ext2/params/(.+)$', ParameterHandler),
@@ -34,18 +40,8 @@ def initialize_handlers(self):
             (r'/simple_ext2/(.*)', ErrorHandler)
         ])
 
-    def initialize_templates(self):
-        jenv_opt = {"autoescape": True}
-        env = jinja2.Environment(
-            loader=jinja2.FileSystemLoader(self.template_paths),
-            extensions=["jinja2.ext.i18n"],
-            **jenv_opt
-        )
-        template_settings = {"simple_ext2_jinja2_env": env}
-        self.settings.update(**template_settings)
-
     def initialize_settings(self):
-        pass
+        self.log.info('Config {}'.format(self.config))
 
 #-----------------------------------------------------------------------------
 # Main entry point

From 295d7c47e9ca01082aa6d4bc7945de6b147cc9ea Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 9 Jan 2020 14:47:00 +0100
Subject: [PATCH 27/30] typo

---
 examples/simple/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 5733f54fea..62a458929f 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -135,7 +135,7 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
 
-> --generate-config returns an execption `"The ExtensionApp has not ServerApp "`
+> --generate-config returns an exception `"The ExtensionApp has not ServerApp "`
 
 The generated configuration should contains the following.
 

From 269fc01ec0cd871ca7de2254e0b4feba09ae92af Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Tue, 14 Jan 2020 19:57:36 +0100
Subject: [PATCH 28/30] add = when passing the SimpleApp1.configA via CLI

---
 examples/simple/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 62a458929f..94b28cde5c 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -105,7 +105,7 @@ Stop any running server (with `CTRL+C`) and start with additional configuration
 The provided settings via CLI will override the configuration that reside in the files (`jupyter_simple_ext1_config.py`...)
 
 ```bash
-jupyter simple-ext1 --SimpleApp1.configA "ConfigA from command line"
+jupyter simple-ext1 --SimpleApp1.configA="ConfigA from command line"
 ```
 
 Check the log, it should return on startup something like the following base on the trait you have defined in the CLI and in the `jupyter_simple_ext1_config.py`.

From 4a64388dbc02dc83eb3ef8eaa6d048f9194e3cb1 Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Thu, 16 Jan 2020 13:12:35 +0100
Subject: [PATCH 29/30] use JinjaMixin

---
 examples/simple/README.md                   | 2 +-
 examples/simple/simple_ext1/application.py  | 4 ++--
 examples/simple/simple_ext1/handlers.py     | 7 ++-----
 examples/simple/simple_ext11/application.py | 2 +-
 examples/simple/simple_ext2/application.py  | 4 ++--
 examples/simple/simple_ext2/handlers.py     | 7 ++-----
 6 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 94b28cde5c..708b5bd2d1 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -135,7 +135,7 @@ Try with the above links to check that only Extension 2 is responding (Extension
 
 Run `jupyter simple-ext11 --generate-config && vi ~/.jupyter/jupyter_config.py`.
 
-> --generate-config returns an exception `"The ExtensionApp has not ServerApp "`
+> TODO `--generate-config` returns an exception `"The ExtensionApp has not ServerApp "`
 
 The generated configuration should contains the following.
 
diff --git a/examples/simple/simple_ext1/application.py b/examples/simple/simple_ext1/application.py
index 83868c0651..3ba0d18599 100644
--- a/examples/simple/simple_ext1/application.py
+++ b/examples/simple/simple_ext1/application.py
@@ -1,13 +1,13 @@
 import os, jinja2
 from traitlets import Unicode
-from jupyter_server.extension.application import ExtensionApp
+from jupyter_server.extension.application import ExtensionApp, ExtensionAppJinjaMixin
 from .handlers import (DefaultHandler, RedirectHandler, 
   ParameterHandler, TemplateHandler, TypescriptHandler, ErrorHandler)
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-class SimpleApp1(ExtensionApp):
+class SimpleApp1(ExtensionAppJinjaMixin, ExtensionApp):
     
     # The name of the extension.
     extension_name = "simple_ext1"
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index 5f21e0220a..959ef9a8db 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -1,4 +1,4 @@
-from jupyter_server.extension.handler import ExtensionHandler
+from jupyter_server.extension.handler import ExtensionHandler, ExtensionHandlerJinjaMixin
 
 class DefaultHandler(ExtensionHandler):
     def get(self):
@@ -22,10 +22,7 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class BaseTemplateHandler(ExtensionHandler):
-    def get_template(self, path):
-        """Return the jinja template object for a given name"""
-        return self.settings['{}_jinja2_env'.format(self.extension_name)].get_template(path)
+class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandler): pass
 
 class TypescriptHandler(BaseTemplateHandler):
     def get(self):
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index 2c39cfe955..2c4d28b7be 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -47,7 +47,7 @@ class SimpleApp11(SimpleApp1):
 
     @observe('ignore_js')
     def _update_ignore_js(self, change):
-        """TODO The observe does not work"""
+        """TODO Does the observe work?"""
         self.log.info('ignore_js has just changed: {}'.format(change))
 
     @property
diff --git a/examples/simple/simple_ext2/application.py b/examples/simple/simple_ext2/application.py
index 1f31b417af..2c26ca9c0a 100644
--- a/examples/simple/simple_ext2/application.py
+++ b/examples/simple/simple_ext2/application.py
@@ -1,12 +1,12 @@
 import os, jinja2
 from traitlets import Unicode
-from jupyter_server.extension.application import ExtensionApp
+from jupyter_server.extension.application import ExtensionApp, ExtensionAppJinjaMixin
 from .handlers import ParameterHandler, TemplateHandler, IndexHandler, ErrorHandler
 
 DEFAULT_STATIC_FILES_PATH = os.path.join(os.path.dirname(__file__), "static")
 DEFAULT_TEMPLATE_FILES_PATH = os.path.join(os.path.dirname(__file__), "templates")
 
-class SimpleApp2(ExtensionApp):
+class SimpleApp2(ExtensionAppJinjaMixin, ExtensionApp):
     
     # The name of the extension.
     extension_name = "simple_ext2"
diff --git a/examples/simple/simple_ext2/handlers.py b/examples/simple/simple_ext2/handlers.py
index 490333ced6..50466943b2 100644
--- a/examples/simple/simple_ext2/handlers.py
+++ b/examples/simple/simple_ext2/handlers.py
@@ -1,4 +1,4 @@
-from jupyter_server.extension.handler import ExtensionHandler
+from jupyter_server.extension.handler import ExtensionHandler, ExtensionHandlerJinjaMixin
 
 class ParameterHandler(ExtensionHandler):
     def get(self, matched_part=None, *args, **kwargs):
@@ -9,10 +9,7 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class BaseTemplateHandler(ExtensionHandler):
-    def get_template(self, name):
-        """Return the jinja template object for a given name"""
-        return self.settings['simple_ext2_jinja2_env'].get_template(name)
+class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandler): pass
 
 class IndexHandler(BaseTemplateHandler):
     def get(self):

From c3a19408bd2455a1806300ff4357333ff472fb0c Mon Sep 17 00:00:00 2001
From: Eric Charles <eric@datalayer.io>
Date: Sat, 29 Feb 2020 10:21:36 +0100
Subject: [PATCH 30/30] align examples to mixin

---
 examples/simple/README.md                   |  6 +++---
 examples/simple/simple_ext1/handlers.py     | 11 ++++++-----
 examples/simple/simple_ext11/application.py |  3 +++
 examples/simple/simple_ext2/handlers.py     |  7 ++++---
 4 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/examples/simple/README.md b/examples/simple/README.md
index 708b5bd2d1..7caa527479 100644
--- a/examples/simple/README.md
+++ b/examples/simple/README.md
@@ -10,8 +10,8 @@ You need `python3` to build and run the server extensions.
 # Clone, create a conda env and install from source.
 git clone https://github.com/jupyter/jupyter_server && \
   cd examples/simple && \
-  conda create -y -n jupyter_server_example python=3.7 && \
-  conda activate jupyter_server_example && \
+  conda create -y -n jupyter-server-example python=3.7 && \
+  conda activate jupyter-server-example && \
   pip install -e .
 ```
 
@@ -154,7 +154,7 @@ Stop any running server and then start the simple-ext11.
 
 ```bash
 jupyter simple-ext11 --hello --simple11-dir any_folder
-# or...
+# TODO FIX the following command, simple11 does not work launching with jpserver_extensions parameter.
 jupyter server --ServerApp.jpserver_extensions="{'simple_ext11': True}" --hello --simple11-dir any_folder
 ```
 
diff --git a/examples/simple/simple_ext1/handlers.py b/examples/simple/simple_ext1/handlers.py
index 959ef9a8db..f635d1e2c1 100644
--- a/examples/simple/simple_ext1/handlers.py
+++ b/examples/simple/simple_ext1/handlers.py
@@ -1,6 +1,7 @@
-from jupyter_server.extension.handler import ExtensionHandler, ExtensionHandlerJinjaMixin
+from jupyter_server.base.handlers import JupyterHandler
+from jupyter_server.extension.handler import ExtensionHandlerMixin, ExtensionHandlerJinjaMixin
 
-class DefaultHandler(ExtensionHandler):
+class DefaultHandler(ExtensionHandlerMixin, JupyterHandler):
     def get(self):
         # The name of the extension to which this handler is linked.
         self.log.info("Extension Name in {} Default Handler: {}".format(self.extension_name, self.extension_name))
@@ -9,11 +10,11 @@ def get(self):
         self.write('<h1>Hello Simple 1 - I am the default...</h1>')
         self.write('Config in {} Default Handler: {}'.format(self.extension_name, self.config))
 
-class RedirectHandler(ExtensionHandler):
+class RedirectHandler(ExtensionHandlerMixin, JupyterHandler):
     def get(self):
         self.redirect("/static/{}/favicon.ico".format(self.extension_name))
 
-class ParameterHandler(ExtensionHandler):    
+class ParameterHandler(ExtensionHandlerMixin, JupyterHandler):    
     def get(self, matched_part=None, *args, **kwargs):
         var1 = self.get_argument('var1', default=None)
         components = [x for x in self.request.path.split("/") if x]
@@ -22,7 +23,7 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandler): pass
+class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandlerMixin, JupyterHandler): pass
 
 class TypescriptHandler(BaseTemplateHandler):
     def get(self):
diff --git a/examples/simple/simple_ext11/application.py b/examples/simple/simple_ext11/application.py
index 2c4d28b7be..d67a211fd9 100644
--- a/examples/simple/simple_ext11/application.py
+++ b/examples/simple/simple_ext11/application.py
@@ -61,6 +61,9 @@ def initialize_settings(self):
         self.log.info('ignore_js: {}'.format(self.ignore_js))
         super().initialize_settings()
 
+    def initialize_handlers(self):
+        super().initialize_handlers()
+
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
diff --git a/examples/simple/simple_ext2/handlers.py b/examples/simple/simple_ext2/handlers.py
index 50466943b2..fb34834688 100644
--- a/examples/simple/simple_ext2/handlers.py
+++ b/examples/simple/simple_ext2/handlers.py
@@ -1,6 +1,7 @@
-from jupyter_server.extension.handler import ExtensionHandler, ExtensionHandlerJinjaMixin
+from jupyter_server.base.handlers import JupyterHandler
+from jupyter_server.extension.handler import ExtensionHandlerMixin, ExtensionHandlerJinjaMixin
 
-class ParameterHandler(ExtensionHandler):
+class ParameterHandler(ExtensionHandlerMixin, JupyterHandler):
     def get(self, matched_part=None, *args, **kwargs):
         var1 = self.get_argument('var1', default=None)
         components = [x for x in self.request.path.split("/") if x]
@@ -9,7 +10,7 @@ def get(self, matched_part=None, *args, **kwargs):
         self.write('<p>var1: {}</p>'.format(var1))
         self.write('<p>components: {}</p>'.format(components))
 
-class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandler): pass
+class BaseTemplateHandler(ExtensionHandlerJinjaMixin, ExtensionHandlerMixin, JupyterHandler): pass
 
 class IndexHandler(BaseTemplateHandler):
     def get(self):