From e3337af95c418b51a2a2f6225728ddf5ae03c531 Mon Sep 17 00:00:00 2001
From: xumin <xumin.zhou@konghq.com>
Date: Wed, 10 Jul 2024 17:50:34 +0800
Subject: [PATCH] fix(plugins): Request-Transformer rename behavior

Fix KAG-4915
---
 .../unreleased/kong/req-trans-rename.yml      |  3 +++
 kong/plugins/request-transformer/access.lua   | 22 ++++++++++------
 spec/01-unit/31-kong_cache_spec.lua           | 25 +++++++++++++++++++
 3 files changed, 42 insertions(+), 8 deletions(-)
 create mode 100644 changelog/unreleased/kong/req-trans-rename.yml
 create mode 100644 spec/01-unit/31-kong_cache_spec.lua

diff --git a/changelog/unreleased/kong/req-trans-rename.yml b/changelog/unreleased/kong/req-trans-rename.yml
new file mode 100644
index 0000000000000..a9474d2f10fc9
--- /dev/null
+++ b/changelog/unreleased/kong/req-trans-rename.yml
@@ -0,0 +1,3 @@
+message: "**Request-Transformer**: Fixed an issue where renamed query parameters, url-encoded body parameters, and json body parameters were not handled properly when target name is the same as the source name in the request."
+type: feature
+scope: Plugin
diff --git a/kong/plugins/request-transformer/access.lua b/kong/plugins/request-transformer/access.lua
index f2b66457809f5..8b8a301e6a50b 100644
--- a/kong/plugins/request-transformer/access.lua
+++ b/kong/plugins/request-transformer/access.lua
@@ -231,8 +231,10 @@ local function transform_querystrings(conf, template_env)
   -- Rename querystring(s)
   for _, old_name, new_name in iter(conf.rename.querystring, template_env) do
     local value = querystring[old_name]
-    querystring[new_name] = value
-    querystring[old_name] = nil
+    if value then
+      querystring[old_name] = nil
+      querystring[new_name] = value
+    end
   end
 
   for _, name, value in iter(conf.replace.querystring, template_env) do
@@ -276,9 +278,11 @@ local function transform_json_body(conf, body, content_length, template_env)
   if content_length > 0 and #conf.rename.body > 0 then
     for _, old_name, new_name in iter(conf.rename.body, template_env) do
       local value = parameters[old_name]
-      parameters[new_name] = value
-      parameters[old_name] = nil
-      renamed = true
+      if value then
+        parameters[old_name] = nil
+        parameters[new_name] = value
+        renamed = true
+      end
     end
   end
 
@@ -327,9 +331,11 @@ local function transform_url_encoded_body(conf, body, content_length, template_e
   if content_length > 0 and #conf.rename.body > 0 then
     for _, old_name, new_name in iter(conf.rename.body, template_env) do
       local value = parameters[old_name]
-      parameters[new_name] = value
-      parameters[old_name] = nil
-      renamed = true
+      if value then
+        parameters[old_name] = nil
+        parameters[new_name] = value
+        renamed = true
+      end
     end
   end
 
diff --git a/spec/01-unit/31-kong_cache_spec.lua b/spec/01-unit/31-kong_cache_spec.lua
new file mode 100644
index 0000000000000..688191c6b63b4
--- /dev/null
+++ b/spec/01-unit/31-kong_cache_spec.lua
@@ -0,0 +1,25 @@
+local cache = require "kong.cache"
+
+local helpers = require "spec.helpers"
+
+local REDIS_HOST = helpers.redis_host
+local REDIS_PORT = helpers.redis_port
+
+describe("kong.cache", function()
+  describe("redis strategy", function()
+    lazy_setup(function()
+      cache.new("my_cache", {
+        shm_name        = "my_cache",
+        cluster_events  = cluster_events,
+        worker_events   = worker_events,
+        ttl             = db_cache_ttl,
+        neg_ttl         = db_cache_neg_ttl or db_cache_ttl,
+        resurrect_ttl   = kong_config.resurrect_ttl,
+        page            = page,
+        cache_pages     = cache_pages,
+        resty_lock_opts = LOCK_OPTS,
+        lru_size        = get_lru_size(kong_config),
+      })
+    end)
+  end)
+end
\ No newline at end of file