Add Bytes and Enum handlers to proto3ConvertFuncs

[gdbelvin]

This is an issue to track the TODO on this line in types.go.

var (
	proto3ConvertFuncs = map[descriptor.FieldDescriptorProto_Type]string{
		descriptor.FieldDescriptorProto_TYPE_STRING:  "runtime.String",
		// FieldDescriptorProto_TYPE_GROUP
		// FieldDescriptorProto_TYPE_MESSAGE
		// FieldDescriptorProto_TYPE_BYTES
		// TODO(yugui) Handle bytes
		descriptor.FieldDescriptorProto_TYPE_UINT32: "runtime.Uint32",
		// FieldDescriptorProto_TYPE_ENUM
		// TODO(yugui) Handle Enum
	}

)

[lucasvo]

Bytes was implemented in: #489

[lucasvo]

@loderunner, thanks for implementing the bytes support.

I've been wondering if anyone ever considered encoding bytes as a hex string instead of base64. I'd love to make this configurable. I've been digging through the different runtime.convert methods to see if there is any support for configuration in runtime.convert or in the ConvertFuncExpr.

grpc-gateway/protoc-gen-grpc-gateway/descriptor/types.go

Line 202 in e651a16

conv, ok := tbl[typ]

But it looks like there isn't really anything that would do something similar.

I might go ahead and propose an implementation but I've wanted to open the discussion here first to hear what you think.

[loderunner]

@lucasvo I went for base64 because it is the standard mapping for protobuf bytes. bytes were already handled for methods other than GET that supported sending JSON in the body. It did indeed use the standard base64 mapping from protobuf. I only added support for bytes fields in as URL variables.

I'm curious as to how you would want to configure this. It seems to me the operation of the gRPC protoc plugin is fully automatic, and based on the HTTP annotations. Also, wouldn't this break the JSON mapping of protocol buffers? How would you handle having a message be hex characters in a URL variable, but base64 in the request body?

I'm interested in how you'd do this, keep me posted if you get started, and don't be shy to ask questions.

[lucasvo]

Thanks for the comment @loderunner

Having spent a bit more time with protobuf in the past couple days your argument makes sense. I didn't know the base64 encoding was a protobuf default.

However one small detail I'm trying to fix is the padding: Is there a way to get it to accept a padded value or remove the padding from the json response body?

# URL is /v1/document/get/{documentIdentifier} & returns the same message  in the body.
$ curl -X GET "https://localhost:8082/v1/document/get/QM%3D%3D" -H "accept: application/json" -k
{"error":"type mismatch, parameter: documentIdentifier, error: illegal base64 data at input byte 2","code":3}

$ curl -X GET "https://localhost:8082/v1/document/get/QM" -H "accept: application/json" -k
{"documentIdentifier":"QA=="}

[loderunner]

I agree. I first thought I'd use url-safe base64 encoding with no padding, to make sure we could send it in a URL. But I now think the discrepancy between the JSON body and the URL variable is unacceptable. We'll just have to make sure unsafe characters are correctly escaped.

I won't be doing it right now, but if you want to check, I can give you a couple of pointers.

• The decoding function
• Decoding BytesValue

You'll want to try replacing base64.RawURLEncoding with base64.StdEncoding. Keep me posted on how this goes.

[lucasvo]

I can take care of changing this. I'll try to get a PR ready for this in the next couple of days.

[lucasvo]

@loderunner Hey, I just tried to get make test to pass and it looks like I'm stuck with incompatible versions. swagger-codegen generates code that references ByteArray in the generated code which is nowhere to be found when I install version 1.2.6 (as described in CONTRIBUTING.md) when I run the newest version of swagger-codegen there are other issues. Do you know what version of swagger-codegen you ran to get it to work?

# github.com/grpc-ecosystem/grpc-gateway/examples/clients/abe/abe
examples/clients/abe/abe/CamelCaseServiceNameApi.go:4:5: imported and not used: "strings"
examples/clients/abe/abe/CamelCaseServiceNameApi.go:5:5: imported and not used: "fmt"
examples/clients/abe/abe/ExamplepbABitOfEverything.go:20:17: undefined: ByteArray

[loderunner]

The CI on travis validates against protoc 3.1.0 and swagger-codegen 2.2.2

Look here and here to get the details.

[lucasvo]

@loderunner would love to get your feedback on #565 !