Support map types

[kyleconroy]

The following proto file results in a swagger definition file that's incorrect.

syntax = "proto3";

package rpx;

import "google/api/annotations.proto";

service Foo {
  // Sends a greeting
  rpc Bar (BarRequest) returns (BarResponse) {
    option (google.api.http) = {
      post: "/bar"
      body: "*"
    };
  }
}

message BarRequest {
  map<string, string> labels = 3;
}

message BarResponse {
}

Maps should be represented as objects, not as arrays of objects with the key and value properties.

{
  "swagger": "2.0",
  "info": {
    "version": "",
    "title": ""
  },
  "schemes": [
    "http",
    "https"
  ],
  "consumes": [
    "application/json"
  ],
  "produces": [
    "application/json"
  ],
  "paths": {
    "/bar": {
      "post": {
        "summary": "Foo.Bar",
        "operationId": "Bar",
        "responses": {
          "default": {
            "description": "Description",
            "schema": {
              "$ref": "#/definitions/rpxBarResponse"
            }
          }
        },
        "parameters": [
          {
            "name": "body",
            "in": "body",
            "required": true,
            "schema": {
              "$ref": "#/definitions/rpxBarRequest"
            }
          }
        ],
        "tags": [
          "Foo"
        ]
      }
    }
  },
  "definitions": {
    "BarRequestLabelsEntry": {
      "type": "object",
      "properties": {
        "key": {
          "type": "string",
          "format": "string"
        },
        "value": {
          "type": "string",
          "format": "string"
        }
      }
    },
    "rpxBarRequest": {
      "type": "object",
      "properties": {
        "labels": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/BarRequestLabelsEntry"
          }
        }
      }
    },
    "rpxBarResponse": {
      "type": "object"
    }
  }
}

[achew22]

Just as background, Maps represented as lists of key value pairs are a holdover from the days of proto2. The whole ecosystem is in a bit of a transitional phase right now.

I believe this is a dupe of #79. The current JSON encoder (if my memory serves me correctly) is doing things in the style of proto2. Changing the JSON encoder is kind of hard to do but I would welcome you to jump into the conversation on that other thread.

[t-yuki]

FYI, I've prototyped swagger support for map recently.
Should I make a pull request?
master...t-yuki:feature/map

[kyleconroy]

@achew22 I don't think it's a dupe of #79. The proto3 JSON mapping says that maps should be encoded as objects, not arrays. More important, the generated swagger document is incorrect. The gateway that's generated from this proto file will not accept the labels property as an array of hashes: it requires an object.

@t-yuki Please do!

[achew22]

Looks like a PR that fixes this was merged. I'm going to close the issue now. If this isn't fixed feel free to reopen it or file another issue.