grpc/grpc-dotnet

Endpoint 'gRPC - Unimplemented service'

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#1,679 opened on Apr 8, 2022

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help wantedquestion

Description

I have a service that is not behaving as it should. While troubleshooting it, I noticed this debug output:

Endpoint 'gRPC - Unimplemented service' with route pattern '{unimplementedService}/{unimplementedMethod}' is valid for the request path ... (the path of the non-working service).

What does this mean? I register my Grpc-service using endpoints.MapGrpcService<InforARIService>();

The actual issue I was troubleshooting is that the Grpc-service is invoked, does it's work correctly and returns a class with two string properties. However, on the wire the response is empty (so the client gets a serialization error):

HTTP/1.1 200 OK
Content-Length: 0
Content-Type: application/grpc-web
Date: Fri, 08 Apr 2022 09:23:39 GMT
Server: Kestrel
Request-Context: appId=cid-v1:87cb2164-3464-497d-a7b4-80e9471bf6c3
Grpc-Status: 0
X-Content-Type-Options: nosniff
Strict-Transport-Security: max-age=31536000

Contributor guide

Tech stack
csharpgrpc
Domain
backendapi
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
basic knowledge of gRPCC#/.NET development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
The issue involves a gRPC Web endpoint returning an empty response despite the service working correctly. Investigate the gRPC Web middleware implementation in grpc dotnet, particularly the response serialization and header handling. Check if the service method's return type is properly serialized by the Protobuf serializer. Look at existing tests for gRPC Web (e.g., in test/Grpc.AspNetCore.Server.Tests/) to understand expected behavior. Also review comments on the issue for any additional context provided by maintainers.