plugin(response-rewrite): rewrite binary data to client by base64 (ap…

…ache#1381)

apisix/plugins/response-rewrite.lua

@@ -33,6 +33,11 @@ local schema = {
             description = "new body for repsonse",
             type = "string",
         },
+        body_base64 = {
+            description = "whether new body for repsonse need base64 decode before return",
+            type = "boolean",
+            default = false,
+        },
         status_code = {
             description = "new status code for repsonse",
             type = "integer",
@@ -77,6 +82,13 @@ function _M.check_schema(conf)
         end
     end
 
+    if conf.body_base64 then
+        local body = ngx.decode_base64(conf.body)
+        if not body then
+            return  false, 'invalid base64 content'
+        end
+    end
+
     return true
 end
 
@@ -85,7 +97,13 @@ do
 
 function _M.body_filter(conf, ctx)
     if conf.body then
-        ngx.arg[1] = conf.body
+
+        if conf.body_base64 then
+            ngx.arg[1] = ngx.decode_base64(conf.body)
+        else
+            ngx.arg[1] = conf.body
+        end
+
         ngx.arg[2] = true
     end
 end

doc/plugins/response-rewrite-cn.md

@@ -31,6 +31,7 @@
 |------- |-----|------|
 |status_code   |可选| 修改上游返回状态码|
 |body          |可选| 修改上游返回的 `body` 内容，如果设置了新内容，header 里面的 content-length 字段也会被去掉|
+|body_base64       |可选| 布尔类型，描述 `body` 字段是否需要 base64 解码之后再返回给客户端，用在某些图片和 Protobuffer 场景|
 |headers       |可选| 返回给客户端的 `headers`，这里可以设置多个。头信息如果存在将重写，不存在则添加。想要删除某个 header 的话，把对应的值设置为空字符串即可|
 
 

doc/plugins/response-rewrite.md

@@ -38,6 +38,7 @@ response rewrite plugin, rewrite the content from upstream.
 |-------         |-----|------|
 |status_code   |optional| New `status code` to client|
 |body          |optional| New `body` to client, and the content-length will be reset too.|
+|body_base64   |optional| This is a boolean value，identify if `body` in configuration need base64 decoded before rewrite to client.|
 |headers             |optional| Set the new `headers` for client, can set up multiple. If it exists already from upstream, will rewrite the header, otherwise will add the header. You can set the corresponding value to an empty string to remove a header. |
 
 ## How To Enable

t/plugin/response-rewrite.t

@@ -124,7 +124,7 @@ property "body" validation failed: wrong type: expected string, got number
                     "plugins": {
                         "response-rewrite": {
                             "headers" : {
-                                "X-Server-id": 3,                
+                                "X-Server-id": 3,
                                 "X-Server-status": "on",
                                 "Content-Type": ""
                             },
@@ -169,7 +169,7 @@ passed
             if not res then
                 ngx.say(err)
                 return
-            end 
+            end
 
             if res.headers['Content-Type'] then
                 ngx.say('fail content-type should not be exist, now is'..res.headers['Content-Type'])
@@ -354,3 +354,76 @@ GET /t
 invalid type as header value
 --- no_error_log
 [error]
+
+
+
+=== TEST 12: set body in base64
+--- 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": {
+                        "response-rewrite": {
+                            "body": "SGVsbG8K",
+                            "body_base64": true
+                        }
+                    },
+                    "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 13: check base64 content
+--- request
+GET /hello
+--- response_body
+Hello
+--- no_error_log
+[error]
+
+
+
+=== TEST 14: set body with not well formed base64
+--- config
+    location /t {
+        content_by_lua_block {
+            local plugin = require("apisix.plugins.response-rewrite")
+            local ok, err = plugin.check_schema({
+                            body = "1",
+                            body_base64 =  true
+            })
+            if not ok then
+                ngx.say(err)
+                return
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+invalid base64 content
+--- no_error_log
+[error]