Fixes #247: nicer error message when back-end does not support basic …

…auth

CHANGELOG.md

@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Raise `ProcessGraphVisitException` from `ProcessGraphVisitor.resolve_from_node()` (instead of generic `ValueError`)
 - `DataCube.linear_scale_range` is now a shortcut for `DataCube.apply(lambda  x:x.x.linear_scale_range( input_min, input_max, output_min, output_max))`.  
    Instead of creating an invalid process graph that tries to invoke linear_scale_range on a datacube directly.
+- Nicer error message when back-end does not support basic auth ([#247](https://github.com/Open-EO/openeo-python-client/issues/247))
 
 
 ### Removed

openeo/capabilities.py

@@ -2,6 +2,8 @@
 from distutils.version import LooseVersion
 from typing import Union
 
+# Is this base class (still) useful?
+
 
 class Capabilities(ABC):
     """Represents capabilities of a connection / back end."""

openeo/rest/connection.py

@@ -270,6 +270,8 @@ def authenticate_basic(self, username: str = None, password: str = None) -> 'Con
         :param username: User name
         :param password: User passphrase
         """
+        if not self.capabilities().supports_endpoint("/credentials/basic", method="GET"):
+            raise OpenEoClientException("This openEO back-end does not support basic authentication.")
         if username is None:
             username, password = self._get_auth_config().get_basic_auth(backend=self._orig_url)
             if username is None:

openeo/rest/rest_capabilities.py

@@ -27,6 +27,12 @@ def has_features(self, method_name):
         # Field: endpoints > ... TODO
         pass
 
+    def supports_endpoint(self, path: str, method="GET"):
+        return any(
+            endpoint.get("path") == path and method.upper() in endpoint.get("methods", [])
+            for endpoint in self.capabilities.get("endpoints", [])
+        )
+
     def currency(self):
         """ Get default billing currency."""
         return self.capabilities.get('billing', {}).get('currency')

tests/rest/test_connection.py

@@ -19,8 +19,11 @@
 from .auth.test_oidc import OidcMock, assert_device_code_poll_sleep, ABSENT
 from .. import load_json_resource
 
+
 API_URL = "https://oeo.test/"
 
+BASIC_ENDPOINTS = [{"path": "/credentials/basic", "methods": ["GET"]}]
+
 # Trick to avoid linting/auto-formatting tools to complain about or fix unused imports of these pytest fixtures
 auth_config = auth_config
 refresh_token_store = refresh_token_store
@@ -193,7 +196,7 @@ def test_connection_other_domain_auth_headers(requests_mock, api_version):
     def debug(request: requests.Request, context):
         return repr(("hello world", request.headers))
 
-    requests_mock.get(API_URL, json={"api_version": api_version})
+    requests_mock.get(API_URL, json={"api_version": api_version, "endpoints": BASIC_ENDPOINTS})
     requests_mock.get(API_URL + 'credentials/basic', json={"access_token": secret})
     requests_mock.get("https://evilcorp.test/download/hello.txt", text=debug)
 
@@ -300,7 +303,8 @@ def test_connection_repr(requests_mock):
     requests_mock.get("https://oeo.test/.well-known/openeo", status_code=200, json={
         "versions": [{"api_version": "1.0.0", "url": "https://oeo.test/openeo/1.x/", "production": True}],
     })
-    requests_mock.get("https://oeo.test/openeo/1.x/", status_code=200, json={"api_version": "1.0.0"})
+    requests_mock.get("https://oeo.test/openeo/1.x/", status_code=200,
+                      json={"api_version": "1.0.0", "endpoints": BASIC_ENDPOINTS})
     requests_mock.get("https://oeo.test/openeo/1.x/credentials/basic", json={"access_token": "w3lc0m3"})
 
     conn = connect("https://oeo.test/")
@@ -360,7 +364,7 @@ def test_api_error_non_json(requests_mock):
 
 def test_create_connection_lazy_auth_config(requests_mock, api_version):
     user, pwd = "john262", "J0hndo3"
-    requests_mock.get(API_URL, json={"api_version": api_version})
+    requests_mock.get(API_URL, json={"api_version": api_version, "endpoints": BASIC_ENDPOINTS})
 
     def text_callback(request, context):
         assert request.headers["Authorization"] == requests.auth._basic_auth_str(username=user, password=pwd)
@@ -413,9 +417,19 @@ def test_create_connection_lazy_refresh_token_store(requests_mock):
         )
 
 
+def test_authenticate_basic_no_support(requests_mock, api_version):
+    requests_mock.get(API_URL, json={"api_version": api_version, "endpoints": []})
+
+    conn = Connection(API_URL)
+    assert isinstance(conn.auth, NullAuth)
+    with pytest.raises(OpenEoClientException, match="does not support basic auth"):
+        conn.authenticate_basic(username="john", password="j0hn")
+    assert isinstance(conn.auth, NullAuth)
+
+
 def test_authenticate_basic(requests_mock, api_version):
     user, pwd = "john262", "J0hndo3"
-    requests_mock.get(API_URL, json={"api_version": api_version})
+    requests_mock.get(API_URL, json={"api_version": api_version, "endpoints": BASIC_ENDPOINTS})
 
     def text_callback(request, context):
         assert request.headers["Authorization"] == requests.auth._basic_auth_str(username=user, password=pwd)
@@ -435,7 +449,7 @@ def text_callback(request, context):
 
 def test_authenticate_basic_from_config(requests_mock, api_version, auth_config):
     user, pwd = "john281", "J0hndo3"
-    requests_mock.get(API_URL, json={"api_version": api_version})
+    requests_mock.get(API_URL, json={"api_version": api_version, "endpoints": BASIC_ENDPOINTS})
 
     def text_callback(request, context):
         assert request.headers["Authorization"] == requests.auth._basic_auth_str(username=user, password=pwd)
@@ -1692,7 +1706,7 @@ def test_paginate_callback(requests_mock):
     lambda con: PGNode("add", x=3, y=5)
 ])
 def test_as_curl(requests_mock, data_factory):
-    requests_mock.get(API_URL, json={"api_version": "1.0.0"})
+    requests_mock.get(API_URL, json={"api_version": "1.0.0", "endpoints": BASIC_ENDPOINTS})
     requests_mock.get(API_URL + 'credentials/basic', json={"access_token": "s3cr6t"})
     con = Connection(API_URL).authenticate_basic("john", "j0hn")
 

tests/rest/test_imagecollectionclient.py

@@ -12,7 +12,10 @@
 
 @pytest.fixture
 def session040(requests_mock):
-    requests_mock.get(API_URL + "/", json={"api_version": "0.4.0"})
+    requests_mock.get(API_URL + "/", json={
+        "api_version": "0.4.0",
+        "endpoints": [{"path": "/credentials/basic", "methods": ["GET"]}]
+    })
     session = openeo.connect(API_URL)
     return session
 

tests/rest/test_job.py

@@ -17,14 +17,20 @@
 
 @pytest.fixture
 def session040(requests_mock):
-    requests_mock.get(API_URL + "/", json={"api_version": "0.4.0"})
+    requests_mock.get(API_URL + "/", json={
+        "api_version": "0.4.0",
+        "endpoints": [{"path": "/credentials/basic", "methods": ["GET"]}]
+    })
     session = openeo.connect(API_URL)
     return session
 
 
 @pytest.fixture
 def con100(requests_mock):
-    requests_mock.get(API_URL + "/", json={"api_version": "1.0.0"})
+    requests_mock.get(API_URL + "/", json={
+        "api_version": "1.0.0",
+        "endpoints": [{"path": "/credentials/basic", "methods": ["GET"]}]
+    })
     con = openeo.connect(API_URL)
     return con
 

tests/test_usecase1.py

@@ -9,6 +9,7 @@
 
 @requests_mock.mock()
 class TestUsecase1(TestCase):
+    _capabilities = {"api_version": "0.4.0", "endpoints": [{"path": "/credentials/basic", "methods": ["GET"]}]}
 
     def setUp(self):
         # configuration phase: define username, endpoint, parameters?
@@ -22,13 +23,13 @@ def setUp(self):
         self.output_file = "/tmp/test.gtiff"
 
     def test_user_login(self, m):
-        m.get("http://localhost:8000/api/", json={"api_version": "0.4.0"})
+        m.get("http://localhost:8000/api/", json=self._capabilities)
         m.get("http://localhost:8000/api/credentials/basic", json={"access_token": "blabla"})
         con = openeo.connect(self.endpoint).authenticate_basic(username=self.auth_id, password=self.auth_pwd)
         assert isinstance(con.auth, BearerAuth)
 
     def test_viewing_list_jobs(self, m):
-        m.get("http://localhost:8000/api/", json={"api_version": "0.4.0"})
+        m.get("http://localhost:8000/api/", json=self._capabilities)
         m.get("http://localhost:8000/api/credentials/basic", json={"access_token": "blabla"})
         job_info = {"job_id": "748df7caa8c84a7ff6e", "status": "running", "created": "2021-02-22T09:00:00Z"}
         m.get("http://localhost:8000/api/jobs", json={"jobs": [job_info]})
@@ -59,7 +60,7 @@ def test_viewing_processes(self, m):
         assert self.process_id in set(p["process_id"] for p in processes)
 
     def test_job_creation(self, m):
-        m.get("http://localhost:8000/api/", json={"api_version": "0.4.0"})
+        m.get("http://localhost:8000/api/", json=self._capabilities)
         m.get("http://localhost:8000/api/credentials/basic", json={"access_token": "blabla"})
         m.post("http://localhost:8000/api/jobs", status_code=201,headers={"OpenEO-Identifier": "748df7caa8c84a7ff6e"})