fix(pdk): make kong.service.request.clear_query_arg encode spaces as …

…%20 instead of + (#14277) ### Summary The `+` encoding is more correct (in query strings), but it seems to cause some problems with some users. As a short-term solution I propose that we just convert `+` to `%20`. This is more in-lines what Nginx and OpenResty seems to be doing as well. Signed-off-by: Aapo Talvensaari <[email protected]>
Kong · Feb 14, 2025 · 479274e · 479274e · github-actions · Feb 14, 2025
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diff --git a/changelog/unreleased/kong/fix-pdk-clear-query-arg-space-encoding.yml b/changelog/unreleased/kong/fix-pdk-clear-query-arg-space-encoding.yml
@@ -0,0 +1,6 @@
+message: |
+   **kong.service.request.clear_query_arg**: Changed the encoding of spaces in query arguments from `+`
+   to `%20` as a short-term solution to an issue that some users are reporting. While the `+` is correct
+   encoding of space in querystrings, Kong uses `%20` in many other APIs (inherited from Nginx / OpenResty)
+type: breaking_change
+scope: Plugin
diff --git a/kong/pdk/service/request.lua b/kong/pdk/service/request.lua
@@ -16,6 +16,7 @@ local table_concat = table.concat
 local type = type
 local string_find = string.find
 local string_sub = string.sub
+local string_gsub = string.gsub
 local string_byte = string.byte
 local string_lower = string.lower
 local normalize_multi_header = checks.normalize_multi_header
@@ -295,7 +296,11 @@ local function new(self)
 
     local args = ngx_var.args
     if args and args ~= "" then
-      ngx_var.args = search_remove(args, name)
+      args = search_remove(args, name)
+      if string_find(args, "+", nil, true) then
+        args = string_gsub(args, "+", "%%20")
+      end
+      ngx_var.args = args
     end
   end
 

diff --git a/t/01-pdk/06-service-request/14-clear_query_arg.t b/t/01-pdk/06-service-request/14-clear_query_arg.t
@@ -232,3 +232,39 @@ GET /t?a=0&d=1&a=2&c=3&a=4&b=5&a=6&d=7&a=8
 query: d=1&c=3&b=5&d=7
 --- no_error_log
 [error]
+
+
+
+=== TEST 8: service.request.clear_query_arg() uses %20 as space instead of +
+--- http_config eval
+qq{
+    $t::Util::HttpConfig
+
+    server {
+        listen unix:$ENV{TEST_NGINX_NXSOCK}/nginx.sock;
+
+        location /t {
+            content_by_lua_block {
+                ngx.say("query: " .. tostring(ngx.var.args))
+            }
+        }
+    }
+}
+--- config
+    location = /t {
+
+        access_by_lua_block {
+            local PDK = require "kong.pdk"
+            local pdk = PDK.new()
+
+            pdk.service.request.clear_query_arg("a")
+        }
+
+        proxy_pass http://unix:/$TEST_NGINX_NXSOCK/nginx.sock;
+    }
+--- request
+GET /t?a=0&c+d=1+2&a=2&c%20d=3%20&a=4&b+d=5&%20a+=6+%20+&+%20+d=+%20+7%20++&a=8
+--- response_body
+query: c%20d=1%202&c%20d=3%20&b%20d=5&%20a%20=6%20%20%20&%20%20%20d=%20%20%207%20%20%20
+--- no_error_log
+[error]