Send GET params for empty request messages

src/connectrpc/_client_shared.py

@@ -30,11 +30,12 @@
 def prepare_get_params(
     codec: Codec, request_data: bytes, headers: HTTPHeaders
 ) -> dict[str, str]:
-    params = {"connect": f"v{CONNECT_PROTOCOL_VERSION}"}
-    if request_data:
-        params["message"] = base64.urlsafe_b64encode(request_data).decode("ascii")
-        params["base64"] = "1"
-        params["encoding"] = codec.name()
+    params = {
+        "connect": f"v{CONNECT_PROTOCOL_VERSION}",
+        "message": base64.urlsafe_b64encode(request_data).decode("ascii"),
+        "base64": "1",
+        "encoding": codec.name(),
+    }
     if "content-encoding" in headers:
         params["compression"] = headers.pop("content-encoding")
     return params

src/connectrpc/_server_async.py

@@ -194,7 +194,7 @@ async def __call__(
 
             if http_method == "GET":
                 query_string = scope.get("query_string", b"").decode("utf-8")
-                query_params = parse_qs(query_string)
+                query_params = parse_qs(query_string, keep_blank_values=True)
                 codec_name = query_params.get("encoding", ("",))[0]
             else:
                 query_params = _UNSET_QUERY_PARAMS

src/connectrpc/_server_sync.py

@@ -353,7 +353,7 @@ def _handle_get_request(
         """Handle GET request with query parameters."""
         try:
             query_string = environ.get("QUERY_STRING", "")
-            params = parse_qs(query_string)
+            params = parse_qs(query_string, keep_blank_values=True)
 
             if "message" not in params:
                 raise ConnectError(

test/test_roundtrip.py

@@ -70,6 +70,46 @@ async def make_hat(self, request, ctx):
     assert response.color == "green"
 
 
+def test_roundtrip_sync_connect_get_empty_request() -> None:
+    class RoundtripHaberdasherSync(HaberdasherSync):
+        def make_hat(self, request, ctx):
+            return Hat(size=request.inches, color="green")
+
+    compression = resolve_compression("identity")
+    app = HaberdasherWSGIApplication(
+        RoundtripHaberdasherSync(), compressions=[compression]
+    )
+    with HaberdasherClientSync(
+        "http://localhost",
+        http_client=SyncClient(WSGITransport(app=app)),
+        send_compression=compression,
+        accept_compression=[compression],
+    ) as client:
+        response = client.make_hat(request=Size(), use_get=True)
+    assert response.size == 0
+    assert response.color == "green"
+
+
+@pytest.mark.asyncio
+async def test_roundtrip_async_connect_get_empty_request() -> None:
+    class RoundtripHaberdasher(Haberdasher):
+        async def make_hat(self, request, ctx):
+            return Hat(size=request.inches, color="green")
+
+    compression = resolve_compression("identity")
+    app = HaberdasherASGIApplication(RoundtripHaberdasher(), compressions=[compression])
+    transport = ASGITransport(app)
+    async with HaberdasherClient(
+        "http://localhost",
+        http_client=Client(transport=transport),
+        send_compression=compression,
+        accept_compression=[compression],
+    ) as client:
+        response = await client.make_hat(request=Size(), use_get=True)
+    assert response.size == 0
+    assert response.color == "green"
+
+
 @pytest.mark.parametrize("proto_json", [False, True])
 @pytest.mark.parametrize("compression_name", ["gzip", "br", "zstd", "identity"])
 @pytest.mark.asyncio