feat: support var in upstream_uri on proxy-rewrite plugin

apisix/plugins/proxy-rewrite.lua

@@ -143,7 +143,7 @@ function _M.rewrite(conf, ctx)
 
     local upstream_uri = ctx.var.uri
     if conf.uri ~= nil then
-        upstream_uri = conf.uri
+        upstream_uri = core.utils.resolve_var(conf.uri, ctx.var)
     elseif conf.regex_uri ~= nil then
         local uri, _, err = re_sub(ctx.var.uri, conf.regex_uri[1],
                                    conf.regex_uri[2], "jo")

doc/plugin-develop.md

@@ -246,11 +246,11 @@ Write the logic of the plugin in the corresponding phase.
 
 ## write test case
 
-For functions, write and improve the test cases of various dimensions, do a comprehensive test for your plugin ! The
+For functions, write and improve the test cases of various dimensions, do a comprehensive test for your plugin! The
 test cases of plugins are all in the "__t/plugin__" directory. You can go ahead to find out. APISIX uses
-[****test-nginx****](https://github.com/openresty/test-nginx) as the test framework. A test case,.t file is usually
+[****test-nginx****](https://github.com/openresty/test-nginx) as the test framework. A test case (.t file) is usually
 divided into prologue and data parts by \__data\__. Here we will briefly introduce the data part, that is, the part
-of the real test case. For example, the key-auth plugin :
+of the real test case. For example, the key-auth plugin:
 
 ```perl
 === TEST 1: sanity
@@ -285,6 +285,10 @@ When we request __/t__, which config in the configuration file, the Nginx will c
 "__no_error_log__" means to check the "__error.log__" of Nginx. There must be no ERROR level record. The log files for the unit test
 are located in the following folder: 't/servroot/logs'.
 
+The above test case represents a simple scenario. Most scenarios will require multiple tests to validate. To do this, create multiple tests `=== TEST 1`, `=== TEST 2`, and so on. These tests will be executed sequentially, allowing you to break down scenarios into a sequence of atomic steps.
+
+Additionally, there are some convenience testing endpoints which can be found [here](https://github.com/apache/apisix/blob/master/t/lib/server.lua#L36). For example, see [proxy-rewrite](https://github.com/apache/apisix/blob/master/t/plugin/proxy-rewrite.lua). In test 42, the upstream `uri` is made to redirect `/test?new_uri=hello` to `/hello` (which always returns `hello world`). In test 43, the response body is confirmed to equal `hello world`, meaning the proxy-rewrite configuration added with test 42 worked correctly.
+
 Refer the following [document](how-to-build.md#test) to setup the testing framework.
 
 ### Attach the test-nginx execution process:

doc/plugins/proxy-rewrite.md

@@ -33,13 +33,13 @@ The `proxy-rewrite` is an upstream proxy information rewriting plugin, which sup
 
 ## Attributes
 
-| Name      | Type          | Requirement | Default | Valid             | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
-| --------- | ------------- | ----------- | ------- | ----------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| scheme    | string        | optional    | "http"  | ["http", "https"] | Upstream new `schema` forwarding protocol.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
-| uri       | string        | optional    |         |                   | Upstream new `uri` forwarding address.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
+| Name      | Type          | Requirement | Default | Valid             | Description                                                  |
+| --------- | ------------- | ----------- | ------- | ----------------- | ------------------------------------------------------------ |
+| scheme    | string        | optional    | "http"  | ["http", "https"] | Upstream new `schema` forwarding protocol.                   |
+| uri       | string        | optional    |         |                   | Upstream new `uri` forwarding address. Supports the use of [Nginx variables](https://nginx.org/en/docs/http/ngx_http_core_module.html). Variables must start with `$`, such as `$arg_name`. |
 | regex_uri | array[string] | optional    |         |                   | Upstream new `uri` forwarding address. Use regular expression to match URL from client, when the match is successful, the URL template will be forwarded upstream. If the match is not successful, the URL from the client will be forwarded to the upstream. When `uri` and` regex_uri` are both exist, `uri` is used first. For example: [" ^/iresty/(.*)/(.*)/(.*)", "/$1-$2-$3"], the first element represents the matching regular expression and the second element represents the URL template that is forwarded to the upstream. |
-| host      | string        | optional    |         |                   | Upstream new `host` forwarding address, example `iresty.com`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
-| headers   | object        | optional    |         |                   | Forward to the new `headers` of the upstream, can set up multiple. If it exists, will rewrite the header, otherwise will add the header. You can set the corresponding value to an empty string to remove a header. Support the use of Nginx variables. Need to start with `$`, such as `client_addr: $remote_addr`: it means that the request header `client_addr` is the client IP.                                                                                                                                                    |
+| host      | string        | optional    |         |                   | Upstream new `host` forwarding address, example `iresty.com`. |
+| headers   | object        | optional    |         |                   | Forward to the new `headers` of the upstream, can set up multiple. If it exists, will rewrite the header, otherwise will add the header. You can set the corresponding value to an empty string to remove a header. Support the use of Nginx variables. Need to start with `$`, such as `client_addr: $remote_addr`: it means that the request header `client_addr` is the client IP. |
 
 ## How To Enable
 

t/plugin/proxy-rewrite.t

@@ -1249,3 +1249,51 @@ version: nginx_var_does_not_exist
 x-real-ip: 127.0.0.1
 --- no_error_log
 [error]
+
+
+
+=== TEST 42: set route(rewrite uri based on ctx.var)
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "plugins": {
+                            "proxy-rewrite": {
+                                "uri": "/$arg_new_uri"
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/test"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 43: hit route(upstream uri: should be /hello)
+--- request
+GET /test?new_uri=hello
+--- response_body
+hello world
+--- no_error_log
+[error]