Fix response transformer hang. See issues #1260 and #1207

kong/plugins/response-transformer/handler.lua

@@ -2,8 +2,12 @@ local BasePlugin = require "kong.plugins.base_plugin"
 local body_filter = require "kong.plugins.response-transformer.body_transformer"
 local header_filter = require "kong.plugins.response-transformer.header_transformer"
 
+local is_body_transform_set = header_filter.is_body_transform_set
+local is_json_body = header_filter.is_json_body
+
 local ResponseTransformerHandler = BasePlugin:extend()
 
+
 function ResponseTransformerHandler:new()
  ResponseTransformerHandler.super.new(self, "response-transformer")
 end
@@ -20,7 +24,8 @@ end
 
 function ResponseTransformerHandler:body_filter(conf)
  ResponseTransformerHandler.super.body_filter(self)
- if body_filter.is_json_body(ngx.header["content-type"]) then
+
+ if is_body_transform_set(conf) and is_json_body(ngx.header["content-type"]) then
  local chunk, eof = ngx.arg[1], ngx.arg[2]
  if eof then
  local body = body_filter.transform_json_body(conf, ngx.ctx.buffer)

kong/plugins/response-transformer/header_transformer.lua

@@ -40,6 +40,10 @@ local function is_body_transform_set(conf)
  return #conf.add.json > 0 or #conf.remove.json > 0 or #conf.replace.json > 0 or #conf.append.json > 0
 end
 
+-- export utility functions
+_M.is_json_body = is_json_body
+_M.is_body_transform_set = is_body_transform_set
+
 ---
 -- # Example:
 -- ngx.headers = header_filter.transform_headers(conf, ngx.headers)

spec/plugins/response-transformer/skip_body_spec.lua

@@ -0,0 +1,85 @@
+-- Related to issue https://github.com/Mashape/kong/issues/1207 
+-- unit test to check body remains unaltered
+describe("response-transformer body-check", function()
+
+ local old_ngx, handler
+
+ setup(function()
+ old_ngx = ngx
+ _G.ngx = { -- busted requires explicit _G to access the global environment
+ log = function() end,
+ header = {
+ ["content-type"] = "application/json",
+ },
+ arg = {},
+ ctx = {
+ buffer = "",
+ },
+ }
+ handler = require("kong.plugins.response-transformer.handler")
+ handler:new()
+ end)
+
+ teardown(function()
+ ngx = old_ngx
+ end)
+
+ it("check the body to remain unaltered if no transforms have been set", function()
+ -- only a header transform, no body changes
+ local conf = {
+ remove = {
+ headers = {"h1", "h2", "h3"},
+ json = {}
+ },
+ add = {
+ headers = {},
+ json = {},
+ },
+ append = {
+ headers = {},
+ json = {},
+ },
+ replace = {
+ headers = {},
+ json = {},
+ },
+ }
+ local body = [[
+
+ {
+ "id": 1,
+ "name": "Some One",
+ "username": "Bretchen",
+ "email": "Not@here.com",
+ "address": {
+ "street": "Down Town street",
+ "suite": "Apt. 23",
+ "city": "Gwendoline"
+ },
+ "phone": "1-783-729-8531 x56442",
+ "website": "hardwork.org",
+ "company": {
+ "name": "BestBuy",
+ "catchPhrase": "just a bunch of words",
+ "bs": "bullshit words"
+ }
+ }
+
+]]
+
+ ngx.arg[1] = body
+ handler:body_filter(conf)
+ local result = ngx.arg[1]
+ ngx.arg[1] = ""
+ ngx.arg[2] = true -- end of body marker
+ handler:body_filter(conf)
+ result = result .. ngx.arg[1]
+
+ -- body filter should not execute, it would parse and reencode the json, removing
+ -- the whitespace. So check equality to make sure whitespace is still there, and hence
+ -- body was not touched.
+ assert.are.same(body, result)
+
+ end)
+
+end)