add

+# coding=utf-8
+"""" Simple DEBUG SERVICE plugin
+
+http://localhost:8080/cgi-bin/qgis_mapserv.cgi?SERVICE=DEBUG
+
+.. note:: This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+"""
+
+__author__ = 'wanzhongping'
+__date__ = '2021-04-20'
+__copyright__ = 'chinadci'
+
+
+import os
+from dmap_server import *
+
+
+class DebugFilter(DmpServerFilter):
+
+    def request_ready(self):
+        handler = self.server_interface().request_handler()
+        params = handler.parameters()
+        if len(params) == 0:
+            return
+        if 'DEBUG' in params:
+            handler.set_parameter('SERVICE', 'DEBUG')
+        print("request_ready")
+
+    def response_complete(self):
+        handler = self.server_interface().request_handler()
+        params = handler.parameters()
+        if len(params) == 0:
+            return
+        if params['service'] != 'DEBUG':
+            return
+
+        headers_dict = handler.request_headers()
+        handler.clear()
+        handler.set_response_header('Status', '200 Ok')
+        handler.append_body(b'<h1>Params</h1>')
+        for param in params:
+            handler.append_body(('<p><b>%s</b> "%s"</p>' % (param.key(), param.data())).encode('utf8'))
+            # handler.append_body('<p><b>%s</b> "%s"</p>' % (param.key(), param.data()))
+
+        handler.append_body('<h1>Headers</h1>'.encode('utf8'))
+        for header in headers_dict:
+            handler.append_body(('<p><b>%s</b> "%s"</p>' % (header.key(), header.data())).encode('utf8'))
+        print("response_complete")
+
+ 
+class Debug:
+
+    def __init__(self, serverIface):
+        # Save reference to the DMap server interface
+        # Higher priority
+        self.debugFilter = DebugFilter(serverIface)
+        serverIface.register_filter(self.debugFilter, 10)
+