feature: supported redirect plugin. (#732)

conf/config.yaml

@@ -87,6 +87,7 @@ plugins:                          # plugin list
   - serverless-post-function
   - openid-connect
   - proxy-rewrite
+  - redirect
 
 stream_plugins:
   - mqtt-proxy

doc/README.md

@@ -53,3 +53,4 @@ Plugins
 * [serverless](plugins/serverless-cn.md)：AllowS to dynamically run Lua code at *different* phase in APISIX.
 * [ip-restriction](plugins/ip-restriction.md): IP whitelist/blacklist.
 * openid-connect
+* [redirect](plugins/redirect.md): URI redirect.

doc/README_CN.md

@@ -54,3 +54,4 @@ Reference document
 * [serverless](plugins/serverless-cn.md)：允许在 APISIX 中的不同阶段动态运行 Lua 代码。
 * [ip-restriction](plugins/ip-restriction-cn.md): IP 黑白名单。
 * openid-connect
+* [redirect](plugins/redirect-cn.md): URI 重定向。

doc/plugins/redirect.md

@@ -0,0 +1,100 @@
+[中文](redirect-cn.md)
+
+# redirect
+
+URI redirect.
+
+### Parameters
+
+|Name    |Required|Description|
+|------- |-----|------|
+|uri     |required| New uri which can contain Ningx variable, eg: `/test/index.html`, `$uri/index.html`. You can refer to variables in a way similar to `${xxx}` to avoid ambiguity, eg: `${uri}foo/index.html`. If you just need the original `$` character, add `\` in front of it, like this one: `/\$foo/index.html`. If you refer to a variable name that does not exist, this will not produce an error, and it will be used as an empty string.|
+|ret_code|option|Response code, the default value is `302`.|
+
+### Example
+
+#### Enable Plugin
+
+Here's a mini example, enable the `redirect` plugin on the specified route:
+
+```shell
+curl http://127.0.0.1:9080/apisix/admin/routes/1 -X PUT -d '
+{
+    "uri": "/test/index.html",
+    "plugins": {
+        "redirect": {
+            "uri": "/test/default.html",
+            "ret_code": 301
+        }
+    },
+    "upstream": {
+        "type": "roundrobin",
+        "nodes": {
+            "127.0.0.1:80": 1
+        }
+    }
+}'
+```
+
+And we can use any Nginx built-in variable in the new URI.
+
+```shell
+curl http://127.0.0.1:9080/apisix/admin/routes/1 -X PUT -d '
+{
+    "uri": "/test",
+    "plugins": {
+        "redirect": {
+            "uri": "$uri/index.html",
+            "ret_code": 301
+        }
+    },
+    "upstream": {
+        "type": "roundrobin",
+        "nodes": {
+            "127.0.0.1:80": 1
+        }
+    }
+}'
+```
+
+#### Test Plugin
+
+Testing based on the above examples :
+
+```shell
+$ curl http://127.0.0.1:9080/test/index.html -i
+HTTP/1.1 301 Moved Permanently
+Date: Wed, 23 Oct 2019 13:48:23 GMT
+Content-Type: text/html
+Content-Length: 166
+Connection: keep-alive
+Location: /test/default.html
+
+...
+```
+
+We can check the response code and the response header `Location`.
+
+It shows that the `redirect` plugin is in effect.
+
+#### Disable Plugin
+
+When you want to disable the `redirect` plugin, it is very simple,
+ you can delete the corresponding json configuration in the plugin configuration,
+  no need to restart the service, it will take effect immediately :
+
+```shell
+curl http://127.0.0.1:9080/apisix/admin/routes/1 -X PUT -d '
+{
+    "uri": "/test/index.html",
+    "plugins": {},
+    "upstream": {
+        "type": "roundrobin",
+        "nodes": {
+            "127.0.0.1:80": 1
+        }
+    }
+}'
+```
+
+The `redirect` plugin has been disabled now. It works for other plugins.

lua/apisix/plugins/redirect.lua

@@ -0,0 +1,119 @@
+local core = require("apisix.core")
+local tab_insert = table.insert
+local tab_concat = table.concat
+local re_gmatch = ngx.re.gmatch
+local ipairs = ipairs
+
+local lrucache = core.lrucache.new({
+    ttl = 300, count = 100
+})
+
+
+local schema = {
+    type = "object",
+    properties = {
+        ret_code = {type = "integer", minimum = 200, default = 302},
+        uri = {type = "string", minLength = 2},
+    },
+    required = {"uri"},
+}
+
+
+local plugin_name = "rewrite"
+
+local _M = {
+    version = 0.1,
+    priority = 900,
+    name = plugin_name,
+    schema = schema,
+}
+
+
+local function parse_uri(uri)
+
+    local reg = [[ (\\\$[0-9a-zA-Z_]+) | ]]         -- \$host
+                .. [[ \$\{([0-9a-zA-Z_]+)\} | ]]    -- ${host}
+                .. [[ \$([0-9a-zA-Z_]+) | ]]        -- $host
+                .. [[ (\$|[^$\\]+) ]]               -- $ or others
+    local iterator, err = re_gmatch(uri, reg, "jiox")
+    if not iterator then
+        return nil, err
+    end
+
+    local t = {}
+    while true do
+        local m, err = iterator()
+        if err then
+            return nil, err
+        end
+
+        if not m then
+            break
+        end
+
+        tab_insert(t, m)
+    end
+
+    return t
+end
+
+
+function _M.check_schema(conf)
+    local ok, err = core.schema.check(schema, conf)
+    if not ok then
+        return false, err
+    end
+
+    local uri_segs, err = parse_uri(conf.uri)
+    if not uri_segs then
+        return false, err
+    end
+    core.log.info(core.json.delay_encode(uri_segs))
+
+    return true
+end
+
+
+    local tmp = {}
+local function concat_new_uri(uri, ctx)
+    local pased_uri_segs, err = lrucache(uri, nil, parse_uri, uri)
+    if not pased_uri_segs then
+        return nil, err
+    end
+
+    core.table.clear(tmp)
+
+    for _, uri_segs in ipairs(pased_uri_segs) do
+        local pat1 = uri_segs[1]    -- \$host
+        local pat2 = uri_segs[2]    -- ${host}
+        local pat3 = uri_segs[3]    -- $host
+        local pat4 = uri_segs[4]    -- $ or others
+        core.log.info("parsed uri segs: ", core.json.delay_encode(uri_segs))
+
+        if pat2 or pat3 then
+            tab_insert(tmp, ctx.var[pat2 or pat3])
+        else
+            tab_insert(tmp, pat1 or pat4)
+        end
+    end
+
+    return tab_concat(tmp, "")
+end
+
+
+function _M.rewrite(conf, ctx)
+    core.log.info("plugin rewrite phase, conf: ", core.json.delay_encode(conf))
+
+    local new_uri, err = concat_new_uri(conf.uri, ctx)
+    if not new_uri then
+        core.log.error("failed to generate new uri by: ", conf.uri, " error: ",
+                       err)
+        core.response.exit(500)
+    end
+
+    core.response.set_header("Location", new_uri)
+    core.response.exit(conf.ret_code)
+end
+
+
+return _M

t/admin/plugins.t

@@ -30,6 +30,6 @@ __DATA__
 --- request
 GET /apisix/admin/plugins/list
 --- response_body_like eval
-qr/\["limit-req","limit-count","limit-conn","key-auth","prometheus","node-status","jwt-auth","zipkin","ip-restriction","grpc-transcode","serverless-pre-function","serverless-post-function","openid-connect","proxy-rewrite"\]/
+qr/\["limit-req","limit-count","limit-conn","key-auth","prometheus","node-status","jwt-auth","zipkin","ip-restriction","grpc-transcode","serverless-pre-function","serverless-post-function","openid-connect","proxy-rewrite","redirect"\]/
 --- no_error_log
 [error]

t/debug/debug-mode.t

@@ -65,6 +65,7 @@ loaded plugin and sort by priority: 1003 name: limit-conn
 loaded plugin and sort by priority: 1002 name: limit-count
 loaded plugin and sort by priority: 1001 name: limit-req
 loaded plugin and sort by priority: 1000 name: node-status
+loaded plugin and sort by priority: 900 name: redirect
 loaded plugin and sort by priority: 506 name: grpc-transcode
 loaded plugin and sort by priority: 500 name: prometheus
 loaded plugin and sort by priority: 0 name: example-plugin