Adding json_serialize and json_deserialize to requests transport (#466)

gql/transport/requests.py

@@ -1,7 +1,7 @@
 import io
 import json
 import logging
-from typing import Any, Collection, Dict, List, Optional, Tuple, Type, Union
+from typing import Any, Callable, Collection, Dict, List, Optional, Tuple, Type, Union
 
 import requests
 from graphql import DocumentNode, ExecutionResult, print_ast
@@ -47,6 +47,8 @@ def __init__(
         method: str = "POST",
         retry_backoff_factor: float = 0.1,
         retry_status_forcelist: Collection[int] = _default_retry_codes,
+        json_serialize: Callable = json.dumps,
+        json_deserialize: Callable = json.loads,
         **kwargs: Any,
     ):
         """Initialize the transport with the given request parameters.
@@ -73,6 +75,10 @@ def __init__(
             should force a retry on. A retry is initiated if the request method is
             in allowed_methods and the response status code is in status_forcelist.
             (Default: [429, 500, 502, 503, 504])
+        :param json_serialize: Json serializer callable.
+                By default json.dumps() function
+        :param json_deserialize: Json deserializer callable.
+                By default json.loads() function
         :param kwargs: Optional arguments that ``request`` takes.
             These can be seen at the `requests`_ source code or the official `docs`_
 
@@ -90,6 +96,8 @@ def __init__(
         self.method = method
         self.retry_backoff_factor = retry_backoff_factor
         self.retry_status_forcelist = retry_status_forcelist
+        self.json_serialize: Callable = json_serialize
+        self.json_deserialize: Callable = json_deserialize
         self.kwargs = kwargs
 
         self.session = None
@@ -174,7 +182,7 @@ def execute(  # type: ignore
             payload["variables"] = nulled_variable_values
 
             # Add the payload to the operations field
-            operations_str = json.dumps(payload)
+            operations_str = self.json_serialize(payload)
             log.debug("operations %s", operations_str)
 
             # Generate the file map
@@ -188,7 +196,7 @@ def execute(  # type: ignore
             file_streams = {str(i): files[path] for i, path in enumerate(files)}
 
             # Add the file map field
-            file_map_str = json.dumps(file_map)
+            file_map_str = self.json_serialize(file_map)
             log.debug("file_map %s", file_map_str)
 
             fields = {"operations": operations_str, "map": file_map_str}
@@ -224,7 +232,7 @@ def execute(  # type: ignore
 
         # Log the payload
         if log.isEnabledFor(logging.INFO):
-            log.info(">>> %s", json.dumps(payload))
+            log.info(">>> %s", self.json_serialize(payload))
 
         # Pass kwargs to requests post method
         post_args.update(self.kwargs)
@@ -257,7 +265,10 @@ def raise_response_error(resp: requests.Response, reason: str):
             )
 
         try:
-            result = response.json()
+            if self.json_deserialize == json.loads:
+                result = response.json()
+            else:
+                result = self.json_deserialize(response.text)
 
             if log.isEnabledFor(logging.INFO):
                 log.info("<<< %s", response.text)
@@ -396,7 +407,7 @@ def _build_batch_post_args(
 
         # Log the payload
         if log.isEnabledFor(logging.INFO):
-            log.info(">>> %s", json.dumps(post_args[data_key]))
+            log.info(">>> %s", self.json_serialize(post_args[data_key]))
 
         # Pass kwargs to requests post method
         post_args.update(self.kwargs)

tests/test_requests.py

@@ -923,3 +923,109 @@ def test_code():
         assert transport.session is None
 
     await run_sync_test(event_loop, server, test_code)
+
+
+@pytest.mark.aiohttp
+@pytest.mark.asyncio
+async def test_requests_json_serializer(
+    event_loop, aiohttp_server, run_sync_test, caplog
+):
+    import json
+    from aiohttp import web
+    from gql.transport.requests import RequestsHTTPTransport
+
+    async def handler(request):
+
+        request_text = await request.text()
+        print("Received on backend: " + request_text)
+
+        return web.Response(
+            text=query1_server_answer,
+            content_type="application/json",
+        )
+
+    app = web.Application()
+    app.router.add_route("POST", "/", handler)
+    server = await aiohttp_server(app)
+
+    url = server.make_url("/")
+
+    def test_code():
+        transport = RequestsHTTPTransport(
+            url=url,
+            json_serialize=lambda e: json.dumps(e, separators=(",", ":")),
+        )
+
+        with Client(transport=transport) as session:
+
+            query = gql(query1_str)
+
+            # Execute query asynchronously
+            result = session.execute(query)
+
+            continents = result["continents"]
+
+            africa = continents[0]
+
+            assert africa["code"] == "AF"
+
+        # Checking that there is no space after the colon in the log
+        expected_log = '"query":"query getContinents'
+        assert expected_log in caplog.text
+
+    await run_sync_test(event_loop, server, test_code)
+
+
+query_float_str = """
+    query getPi {
+      pi
+    }
+"""
+
+query_float_server_answer_data = '{"pi": 3.141592653589793238462643383279502884197}'
+
+query_float_server_answer = f'{{"data":{query_float_server_answer_data}}}'
+
+
+@pytest.mark.aiohttp
+@pytest.mark.asyncio
+async def test_requests_json_deserializer(event_loop, aiohttp_server, run_sync_test):
+    import json
+    from aiohttp import web
+    from decimal import Decimal
+    from functools import partial
+    from gql.transport.requests import RequestsHTTPTransport
+
+    async def handler(request):
+        return web.Response(
+            text=query_float_server_answer,
+            content_type="application/json",
+        )
+
+    app = web.Application()
+    app.router.add_route("POST", "/", handler)
+    server = await aiohttp_server(app)
+
+    url = server.make_url("/")
+
+    def test_code():
+
+        json_loads = partial(json.loads, parse_float=Decimal)
+
+        transport = RequestsHTTPTransport(
+            url=url,
+            json_deserialize=json_loads,
+        )
+
+        with Client(transport=transport) as session:
+
+            query = gql(query_float_str)
+
+            # Execute query asynchronously
+            result = session.execute(query)
+
+            pi = result["pi"]
+
+            assert pi == Decimal("3.141592653589793238462643383279502884197")
+
+    await run_sync_test(event_loop, server, test_code)