application/x-www-form-urlencoded support.

[Miladrzh]

Hello to all grpc-gateway community.

I have a api call which its request is post and data come in application/x-www-form-urlencoded format

for example:

foo=bar&something=somethingelse

But grpc-gateway cant serialize it into my request.
i use proto3 and my request is like

message Req{
    string token = 1;
    string body = 3;
}

rpc SamanPayPostCallback(Req) returns (google.api.HttpBody) {
        option (google.api.http) = {
            post: "/x/{token}"
            body: "body"
        };
}

I try to serialize it like strings or like bytes but none of them work correct even in bytes.

i get this error when i call my api with this body

foo=bar&something=somethingelse

"invalid character 'f' looking for beginning of value"

Can anybody help me what should i do?

[johanbrandhorst]

@Miladrzh thanks for your bug report. We do test this in our integration tests, so it should be working: https://github.com/grpc-ecosystem/grpc-gateway/blob/master/examples/integration/integration_test.go#L1502. The main difference is that our integration tests use a "GET" request for this:
https://github.com/grpc-ecosystem/grpc-gateway/blob/master/examples/proto/examplepb/a_bit_of_everything.proto#L441. Maybe try that?

[johanbrandhorst]

Looking at the code, I think the problem is that you've defined it as POST actually. Why aren't you using JSON if you're using a post request?

[johanbrandhorst]

Take a look at the source:

grpc-gateway/runtime/mux.go

Line 249 in 0d29f14

for m, handlers := range s.handlers {

. It will allow falling back to POST if it doesn't already match anything. I think if you want to use POST and application/x-www-form-urlencoded you have to define a custom marshaller.

[Miladrzh]

Unfortunatelly, i can't change the request cause it comes from outside resources which that protocol is like that.

I know it needs a custom marshaller but does grpc-gateway have plan to implement this marshaller?

As many framework like django recognize post in application/x-www-form-urlencoded format.

[johanbrandhorst]

You can implement your own Marshaler and hand it to runtime.WithMarshalerOption: https://godoc.org/github.com/grpc-ecosystem/grpc-gateway/runtime#WithMarshalerOption.

[johanbrandhorst]

If you implement a form marshaler and would like to contribute it back to us, you're welcome to do so. I will close this issue as I think there's a clear path forward. Please let me know if you need more help.