how to output field as an array of json values?

[MaerF0x0]

If it makes it easier they can be the "simple" types (number, bool, null, string ... not array or object)

I'm trying to send a message like

my.proto:

Items {
 repeated <what here?> data =1;
}

I would like it to be
{"items":{"data": ["hi", 123, false, null]}}

bytes gives me a base64 encoded string
repeated bytes gives me an array of base64 encoded strings

[MaerF0x0]

It looks like maybe? https://godoc.org/github.com/golang/protobuf/ptypes/struct#ListValue Just figuring out how to use it now.

[MaerF0x0]

ListValue did it. It looks like one probably can use those types to force whatever json kinds one wants @yugui Do you want me to contrib some docs to help the next person?

[tmc]

@MaerF0x0 a documentation addition for this would be /super/ helpful for other folks down the line. Please do!

[achew22]

@MaerF0x0, to echo Travis' comment, even a code snippet in here would be really interesting to see. Thanks for digging in!

I'm going to close this PR since it seems you've got it figured out but I would like to see if it's possible to add some docs on this.

[MaerF0x0]

So I finally figure how to abuse grpc-gateway to make it have the HTTP interface we want, but now the go code is heinous. :-/

syntax = "proto3";

package somesvc;

import "google/api/annotations.proto";
import "google/protobuf/struct.proto";

service SomeSvc {
  rpc OutgoingListValues(Nil) returns (stream SomeListValues) {
    option (google.api.http) = {
      get: "/listvalue"
    };
  }

  rpc IncomingListValues(SliceListValues) returns (Nil) {
    option (google.api.http) = {
      post: "/listvalue"
      body: "*"
    };
  }

}

message Nil {}

message SliceListValues{
  repeated google.protobuf.ListValue rows = 1;  // json => {"rows": [["a", 1, true, null],...]}
}

message SomeListValues{
  google.protobuf.ListValue row = 1;  // stream of json => {"row": ["a", 1, true, null]}
}

but the outgoing go looks like this (absurd).

	srv.Send(&somesvc.SomeListValues{
		Row: &structpb.ListValue{
			Values: []*structpb.Value{
				&structpb.Value{Kind: &structpb.Value_StringValue{StringValue: "a"}},
				&structpb.Value{Kind: &structpb.Value_NumberValue{NumberValue: 1.0}},
				&structpb.Value{Kind: &structpb.Value_BoolValue{BoolValue: false}},
				&structpb.Value{Kind: &structpb.Value_NullValue{NullValue: structpb.NullValue_NULL_VALUE}},
			},
		},
	})

ideally it would just be:

	srv.Send([]interface{}{"a", 1.0, true, nil})

[MaerF0x0]

@achew22 Let me know if you'd like some docs surrounding ^^? I learned how to use the google well known types to make GRPC-gateway have the interface I like, but it also means the GRPCServer interface becomes gnarly.

[achew22]

I'm not 100% sure on this since I can't see your code, but I would bet that you could create a helper method much like proto.String (or the other types) like this:

func StringValue(v string) *structpb.StringValue {
  return &structpb.StringValue(Kind: &structpb.Value_StringValue{StringValue: "a"}})
}
// ... et al

Usage might look like:

	srv.Send(&somesvc.SomeListValues{
		Row: &structpb.ListValue{
			Values: []*structpb.Value{
				StringValue("a"},
				NumberValue(1.0),
				BoolValue(false),
				NullValue(null), // enums are hard and you might have to check if the value is nil here instead of doing it on type.
			},
		},
	})

Or you could write an even more high level abstraction to translate from (I wouldn't do this, it feels kind of icky)

func (r *Receiver) func SendIt(srv Yourtype, v []interface{}) {
	r := &somesvc.SomeListValues{
		Rows: &structpb.ListValue{
			Values: []*structpb.Value{},
		}
	}
	for _, k := range v {
		switch s := v.(type) {
		case string:
			r.Rows.Values = append(r.Rows.Values, &structpb.Value_StringValue{StringValue: s}}
			break
		// ... More types
		case default:
			panic("This is unimplemented so bail")
	}
	return r.srv.Send(r)
}

That said, you're not forced to use go as your langage for server writing. If you think you can do better in python, c++, javascript or any of the other gRPC languages you can write your server in that.