Hi,
Since I am newish to gRPC, I would greatly appreciate your help and advice. *Adding some context* I would like to consume a 3rd party gRPC server, in my case it is a high-end router, actually there are many of those running different versions of gRPC servers, but I'll use a simple example (details below) to demonstrate my issue/question. In such a scenario, I am ok avoiding gRPC stubs and dealing only with (de)serialising messages. Better to declare an endpoint and a body than producing and using code for it. I would like to a HTTP/2 client to consume the gRPC response. *What the docs say about protobuf* Based on (just an example, every lang has a method to convert a Protobuf encode message to JSON) https://googleapis.dev/python/protobuf/latest/google/protobuf/json_format.html I would like to decode protobuf encoded messages to json *What the docs say about gRPC* Based on https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md it is doable to use a HTTP2 client if you specify the Content-Type (to be application/grpc+proto) and a 5 byte header in each request: Length-Prefixed-Message (use 0x00 for Compressed-Flag) Message-Length *Running a gRPC server as an example* I tried to find a playground/public gRPC server, but no luck, so I am using the introductory (hello world) example in the official page of gRPC https://grpc.io/docs/languages/go/quickstart/ $ go run greeter_server/main.go # from one terminal *Running a gRPC client (grpcurl) as a method to verify* $ wget https: //github.com/fullstorydev/grpcurl/releases/download/v1.6.1/grpcurl_1.6.1_linux_x86_64.tar.gz $ cp grpcurl_1.6.1_linux_x86_64/grpcurl /usr/local/sbin/ $ cd grpc-go/examples/helloworld $ grpcurl -import-path ./helloworld -proto helloworld.proto list $ grpcurl -import-path ./helloworld -proto helloworld.proto describe helloworld.Greeter $ grpcurl -plaintext -import-path ./helloworld -proto helloworld.proto 127.0.0.1:50051 helloworld.Greeter/SayHello { "message": "Hello " } *Making the gRPC calll (using a HTTP/2 client)* iex(8)> len = 0 iex(9)> body = IO.iodata_to_binary([<<0::unsigned-integer-size(8)-big>>, << len::unsigned-integer-size(32)-big>>]) <<0, 0, 0, 0, 0>> iex(10)> {:ok, conn, request_ref} = Mint.HTTP2.request(conn, "POST", "helloworld.Greeter/SayHello", _headers = [{"content-type", "application/grpc+proto"}], body) where <<0::unsigned-integer-size(8)-big>> is the *Compressed-Flag*, <<len::unsigned-integer-size(32)-big>> is the *Message-Length* But I don't receive a valid HTTP response. *Question* Would you be so kind to point me to an example how-to achieve this? Are you able to use a HTTP/2 client to make a gRPC call? (without decoding the body for now) -- You received this message because you are subscribed to the Google Groups "grpc.io" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/grpc-io/983b704a-7867-49ac-95c1-bd8103721d0fo%40googlegroups.com.
