gRPC JSON transcoding fails for HTTP paths containing ':'

[mikeas1]

What version of gRPC and what language are you using?

C# .NET 7.0
gRPC.Core 2.46.5
Microsoft.AspNetCore.Grpc.JsonTranscoding 7.0.3

What operating system (Linux, Windows,...) and version?

Debian Linux

What runtime / compiler are you using (e.g. .NET Core SDK version dotnet --info)

dotnet --info
.NET SDK:
Version: 7.0.102
Commit: 4bbdd14480

Runtime Environment:
OS Name: debian
OS Version: rodete
OS Platform: Linux
RID: linux-x64
Base Path: /usr/share/dotnet/sdk/7.0.102/

Host:
Version: 7.0.2
Architecture: x64
Commit: d037e070eb

.NET SDKs installed:
6.0.405 [/usr/share/dotnet/sdk]
7.0.102 [/usr/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.13 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.2 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.13 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.2 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

What did you do?

Annotate a gRPC method using the recommended "custom method" syntax, which includes a : in the path. Example:

  rpc StartFrameImport(StartFrameImportRequest)
      returns (StartFrameImportResponse) {
    option (google.api.http) = {
      post: "/v1/frames:startFrameImport",
      body: "*",
    };
  }
  rpc GetFrameImport(GetFrameImportRequest) returns (GetFrameImportResponse) {
    option (google.api.http) = {
      post: "/v1/frames:getFrameImport",
      body: "*",
    };
  }

Call the gRPC endpoint with JSON transcoding:

$ curl -v http://localhost:5001/v1/frames:startFrameImport -x POST

Receive 404 response

info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished HTTP/1.1 GET http://localhost:5001/v1/frames:startFrameImport - - - 404 0 - 93.2833ms

Call the incorrectly parsed endpoint with JSON transcoding:

$ curl -v http://localhost:5001/v1/frames -x POST

Receive an error:

Microsoft.AspNetCore.Routing.Matching.AmbiguousMatchException: The request matched multiple endpoints. Matches: 
                                                                      
gRPC - /v1/frames
gRPC - /v1/frames 
   at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ReportAmbiguity(CandidateState[] candidateState)
   at Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ProcessFinalCandidates(HttpContext httpContext, CandidateState[] candidateState)
   at Microsoft.AspNetCore.Routing.Matching.DfaMatcher.MatchAsync(HttpContext httpContext)
   at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)

What did you expect to see?

Request should be correctly routed to the gRPC method with that path.

What did you see instead?

Request returns 404 due to incorrectly parsed HTTP paths.

I believe the underlying problem is that the custom verb is dropped when converting from a Grpc.Shared.HttpRoutePattern (which correctly parses the :myMethod suffix) to a Microsoft.AspNetCore.Grpc.JsonTranscoding.Internal.JsonTranscodingRouteAdapter.

Anything else we should know about your project / environment?

[Jeevananthan-23]

Hi, is it possible to add .net6 gRPC server with .net7 gRPC client to access REST api endpoints? (i.e). GRPC Jsontranscoding only supports in .net7 generating protobuf files in .net7 and share it with .net6 class lib here the .net7 client should accept the ingest request and route to .net6 server to read it back and sends the response.

[JamesNK]

This is fixed. Unfortunately, it will be some time (2 months?) before it's available in 7.0.6. It missed the cutoff for the next service patch.

You could reference the package from the .NET 8 internal feed - https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet8/nuget/v3/index.json - the fix is there now. However, I think that will only work if you're targeting .NET 8.

Otherwise, don't use verb until the fix is available.