Awesome! That was it :) > Also, I had mentioned in chat that the problem may have been as simple as > using "helloworld.Greeter/SayHello" instead of "/helloworld.Greeter/SayHello" > (missing / at beginning). In gRPC we commonly talk about service/method, > without the leading slash. But in HTTP it has the leading slash since it is a > path.
Thanks Eric for all the help! > On 21 Jul 2020, at 17:20, Eric Anderson <[email protected]> wrote: > > Oh, I should mention one thing about using curl like that: it doesn't support > trailers. Right now the Java server just issues a warning in such cases, but > it should probably be failing. You can "fake" it by passing "-H te:trailers" > to curl, which will make the server happy but still doesn't let you see the > gRPC status. > > Also, I had mentioned in chat that the problem may have been as simple as > using "helloworld.Greeter/SayHello" instead of "/helloworld.Greeter/SayHello" > (missing / at beginning). In gRPC we commonly talk about service/method, > without the leading slash. But in HTTP it has the leading slash since it is a > path. > > On Tue, Jul 21, 2020 at 8:15 AM Eric Anderson <[email protected] > <mailto:[email protected]>> wrote: > Here is the most basic gRPC call using curl: > > $ echo -ne '\000\000\000\000\000' | curl --http2-prior-knowledge > http://localhost:50051/helloworld.Greeter/SayHello > <http://localhost:50051/helloworld.Greeter/SayHello> -H > content-type:application/grpc --data-binary @- | od -t x1 > 0000000 00 00 00 00 08 0a 06 48 65 6c 6c 6f 20 > 0000015 > > That sends an uncompressed zero-byte request (so the 'name' sent to the > hello-world server would be empty string). The response is an uncompressed > 8-byte response with the string "Hello ". You can pass '-v' to curl to see > more information. > > On Tue, Jul 21, 2020 at 7:28 AM <[email protected] > <mailto:[email protected]>> wrote: > 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 > > <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 > <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/ > <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 > > <http://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 <http://grpc.io/>" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[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 > > <https://groups.google.com/d/msgid/grpc-io/983b704a-7867-49ac-95c1-bd8103721d0fo%40googlegroups.com?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "grpc.io" group. 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