feat: add allow_origins_by_regex to cors plugin

apisix/plugins/cors.lua

@@ -19,6 +19,9 @@ local ngx         = ngx
 local plugin_name = "cors"
 local str_find    = core.string.find
 local re_gmatch   = ngx.re.gmatch
+local re_compile = require("resty.core.regex").re_match_compile
+local re_find = ngx.re.find
+local ipairs = ipairs
 
 
 local lrucache = core.lrucache.new({
@@ -73,7 +76,20 @@ local schema = {
                 "if you set this option to 'true', you can not use '*' for other options.",
             type = "boolean",
             default = false
-        }
+        },
+        allow_origins_by_regex = {
+            type = "array",
+            description =
+                "you can use regex to allow specific origins when no credentials," ..
+                "for example use [.*\\.test.com] to allow a.test.com and b.test.com",
+            items = {
+                type = "string",
+                minLength = 1,
+                maxLength = 4096,
+            },
+            minItems = 1,
+            uniqueItems = true,
+        },
     }
 }
 
@@ -121,6 +137,14 @@ function _M.check_schema(conf)
             return false, "you can not set '*' for other option when 'allow_credential' is true"
         end
     end
+    if conf.allow_origins_by_regex then
+        for i, re_rule in ipairs(conf.allow_origins_by_regex) do
+            local ok, err = re_compile(re_rule, "j")
+            if not ok then
+                return false, err
+            end
+        end
+    end
 
     return true
 end
@@ -133,7 +157,7 @@ local function set_cors_headers(conf, ctx)
     end
 
     core.response.set_header("Access-Control-Allow-Origin", ctx.cors_allow_origins)
-    if ctx.cors_allow_origins ~= "*" then
+    if ctx.cors_allow_origins ~= "*" or conf.allow_origins_by_regex ~= nil then
         core.response.add_header("Vary", "Origin")
     end
 
@@ -151,17 +175,8 @@ local function set_cors_headers(conf, ctx)
     end
 end
 
-
-function _M.rewrite(conf, ctx)
-    if ctx.var.request_method == "OPTIONS" then
-        return 200
-    end
-end
-
-
-function _M.header_filter(conf, ctx)
+local function process_with_allow_origins(conf, ctx, req_origin)
     local allow_origins = conf.allow_origins
-    local req_origin = core.request.header(ctx, "Origin")
     if allow_origins == "**" then
         allow_origins = req_origin or '*'
     end
@@ -179,8 +194,55 @@ function _M.header_filter(conf, ctx)
         end
     end
 
-    ctx.cors_allow_origins = allow_origins
-    set_cors_headers(conf, ctx)
+    return allow_origins
+end
+
+local function process_with_allow_origins_by_regex(conf, ctx, req_origin)
+    if conf.allow_origins_by_regex == nil then
+        return
+    end
+
+    if not conf.allow_origins_by_regex_rules_concat then
+        local allow_origins_by_regex_rules = {}
+        for i, re_rule in ipairs(conf.allow_origins_by_regex) do
+            allow_origins_by_regex_rules[i] = re_rule
+        end
+        conf.allow_origins_by_regex_rules_concat = core.table.concat(
+            allow_origins_by_regex_rules, "|")
+    end
+
+    -- core.log.warn("regex: ", conf.allow_origins_by_regex_rules_concat, "\n ")
+    local matched = re_find(req_origin, conf.allow_origins_by_regex_rules_concat, "jo")
+    if matched then
+        return req_origin
+    end
+end
+
+
+local function match_origins(req_origin, allow_origins)
+    return req_origin == allow_origins or allow_origins == '*'
+end
+
+
+function _M.rewrite(conf, ctx)
+    if ctx.var.request_method == "OPTIONS" then
+        return 200
+    end
+end
+
+
+function _M.header_filter(conf, ctx)
+    local req_origin = core.request.header(ctx, "Origin")
+    -- Try allow_origins first, if mismatched, try allow_origins_by_regex.
+    local allow_origins
+    allow_origins = process_with_allow_origins(conf, ctx, req_origin)
+    if not match_origins(req_origin, allow_origins) then
+        allow_origins = process_with_allow_origins_by_regex(conf, ctx, req_origin)
+    end
+    if allow_origins then
+        ctx.cors_allow_origins = allow_origins
+        set_cors_headers(conf, ctx)
+    end
 end
 
 return _M

docs/en/latest/plugins/cors.md

@@ -43,6 +43,7 @@ title: cors
 | expose_headers   | string  | optional    | "*"     |       | Which headers are allowed to set in response when access cross-origin resource. Multiple value use `,` to split. |
 | max_age          | integer | optional    | 5       |       | Maximum number of seconds the results can be cached.. Within this time range, the browser will reuse the last check result. `-1` means no cache. Please note that the maximum value is depended on browser, please refer to [MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age#Directives) for details. |
 | allow_credential | boolean | optional    | false   |       | Enable request include credential (such as Cookie etc.). According to CORS specification, if you set this option to `true`, you can not use '*' for other options. |
+| allow_origins_by_regex | array | optional    | nil   |       | Use regex expressions to match which origin is allowed to enable CORS, for example, [".*\.test.com"] can use to match all subdomain of test.com  |
 
 > **Tips**
 >

docs/zh/latest/plugins/cors.md

@@ -43,6 +43,7 @@ title: cors
 | expose_headers   | string  | 可选   | "*"    |        | 允许跨域访问时响应方携带哪些非 `CORS规范` 以外的 Header， 多个值使用 `,` 分割。 |
 | max_age          | integer | 可选   | 5      |        | 浏览器缓存 CORS 结果的最大时间，单位为秒，在这个时间范围内浏览器会复用上一次的检查结果，`-1` 表示不缓存。请注意各个浏览器允许的的最大时间不同，详情请参考 [MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Max-Age#Directives)。 |
 | allow_credential | boolean | 可选   | false  |        | 是否允许跨域访问的请求方携带凭据（如 Cookie 等）。根据 CORS 规范，如果设置该选项为 `true`，那么将不能在其他选项中使用 `*`。 |
+| allow_origins_by_regex | array | 可选   | nil  |        | 使用正则表达式数组来匹配允许跨域访问的 Origin, 如[".*\.test.com"] 可以匹配任何test.com的子域名`*`。 |
 
 > **提示**
 >

t/plugin/cors.t

@@ -757,4 +757,173 @@ GET /t
 --- response_body eval
 qr/failed to check the configuration of plugin cors err: you can not/
 --- no_error_log
+
+
+
+=== TEST 28: set route (regex specified)
+--- 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": {
+                        "cors": {
+                            "allow_origins": "http://sub.domain.com,http://sub2.domain.com",
+                            "allow_methods": "GET,POST",
+                            "allow_headers": "headr1,headr2",
+                            "expose_headers": "ex-headr1,ex-headr2",
+                            "max_age": 50,
+                            "allow_credential": true,
+                            "allow_origins_by_regex":[".*\\.test.com"]
+                        }
+                    },
+                    "upstream": {
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        },
+                        "type": "roundrobin"
+                    },
+                    "uri": "/hello"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 29: regex specified
+--- request
+GET /hello HTTP/1.1
+--- more_headers
+Origin: http://a.test.com
+resp-vary: Via
+--- response_body
+hello world
+--- response_headers
+Access-Control-Allow-Origin: http://a.test.com
+Vary: Via, Origin
+Access-Control-Allow-Methods: GET,POST
+Access-Control-Allow-Headers: headr1,headr2
+Access-Control-Expose-Headers: ex-headr1,ex-headr2
+Access-Control-Max-Age: 50
+Access-Control-Allow-Credentials: true
+--- no_error_log
+[error]
+
+
+
+=== TEST 30: regex specified not match
+--- request
+GET /hello HTTP/1.1
+--- more_headers
+Origin: http://a.test2.com
+resp-vary: Via
+--- response_body
+hello world
+--- response_headers
+Access-Control-Allow-Origin:
+Access-Control-Allow-Methods:
+Access-Control-Allow-Headers:
+Access-Control-Expose-Headers:
+Access-Control-Max-Age:
+Access-Control-Allow-Credentials:
+--- no_error_log
+[error]
+
+
+
+=== TEST 31: set route (multiple regex specified )
+--- 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": {
+                        "cors": {
+                            "allow_origins": "http://sub.domain.com,http://sub2.domain.com",
+                            "allow_methods": "GET,POST",
+                            "allow_headers": "headr1,headr2",
+                            "expose_headers": "ex-headr1,ex-headr2",
+                            "max_age": 50,
+                            "allow_credential": true,
+                            "allow_origins_by_regex":[".*\\.test.com",".*\\.example.org"]
+                        }
+                    },
+                    "upstream": {
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        },
+                        "type": "roundrobin"
+                    },
+                    "uri": "/hello"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 32: multiple regex specified match
+--- request
+GET /hello HTTP/1.1
+--- more_headers
+Origin: http://foo.example.org
+resp-vary: Via
+--- response_body
+hello world
+--- response_headers
+Access-Control-Allow-Origin: http://foo.example.org
+Vary: Via, Origin
+Access-Control-Allow-Methods: GET,POST
+Access-Control-Allow-Headers: headr1,headr2
+Access-Control-Expose-Headers: ex-headr1,ex-headr2
+Access-Control-Max-Age: 50
+Access-Control-Allow-Credentials: true
+--- no_error_log
+[error]
+
+
+
+=== TEST 33: multiple regex specified not match
+--- request
+GET /hello HTTP/1.1
+--- more_headers
+Origin: http://foo.example.com
+resp-vary: Via
+--- response_body
+hello world
+--- response_headers
+Access-Control-Allow-Origin:
+Access-Control-Allow-Methods:
+Access-Control-Allow-Headers:
+Access-Control-Expose-Headers:
+Access-Control-Max-Age:
+Access-Control-Allow-Credentials:
+--- no_error_log
 [error]