🐛 fix unquote issue with querystring handling. (#1264)

* 🐛 fix unquote issue with querystring handling.

* 🎨 fix flake8

* 📝 Add comment regarding query string handling for clarity.

---------

Co-authored-by: shane <[email protected]>

Author: monkut

tests/tests.py

@@ -2768,7 +2768,37 @@ def test_wsgi_query_string_unquoted(self):
             "requestContext": {},
         }
         request = create_wsgi_request(event)
-        self.assertEqual(request["QUERY_STRING"], "a=A,B&b=C#D")
+        expected = "a=A%2CB&b=C%23D"  # unencoded result: "a=A,B&b=C#D"
+        self.assertEqual(request["QUERY_STRING"], expected)
+
+    def test_wsgi_query_string_ampersand_unencoded(self):
+        event = {
+            "body": None,
+            "headers": {},
+            "pathParameters": {},
+            "path": "/path/path1",
+            "httpMethod": "GET",
+            "queryStringParameters": {
+                "test": "M&M",
+            },
+            "requestContext": {},
+        }
+        request = create_wsgi_request(event)
+        self.assertEqual(request["QUERY_STRING"], "test=M%26M")
+
+    def test_wsgi_query_string_with_encodechars(self):
+        event = {
+            "body": None,
+            "headers": {},
+            "pathParameters": {},
+            "path": "/path/path1",
+            "httpMethod": "GET",
+            "queryStringParameters": {"query": "Jane&John", "otherquery": "B", "test": "hello+m.te&how&are&you"},
+            "requestContext": {},
+        }
+        request = create_wsgi_request(event)
+        expected = "query=Jane%26John&otherquery=B&test=hello%2Bm.te%26how%26are%26you"
+        self.assertEqual(request["QUERY_STRING"], expected)
 
 
 if __name__ == "__main__":

zappa/wsgi.py

@@ -36,13 +36,16 @@ def create_wsgi_request(
     # we have to check for the existence of one and then fall back to the
     # other.
 
+    # Assumes that the lambda event provides the unencoded string as
+    # the value in "queryStringParameters"/"multiValueQueryStringParameters"
+    # The QUERY_STRING value provided to WSGI expects the query string to be properly urlencoded.
+    # See https://github.com/zappa/Zappa/issues/1227 for discussion of this behavior.
     if "multiValueQueryStringParameters" in event_info:
         query = event_info["multiValueQueryStringParameters"]
         query_string = urlencode(query, doseq=True) if query else ""
     else:
         query = event_info.get("queryStringParameters", {})
         query_string = urlencode(query) if query else ""
-    query_string = unquote(query_string)
 
     if context_header_mappings:
         for key, value in context_header_mappings.items():