Specify a custom Content-Type for Goa errors and MediaTypes, Types

[dobegor]

Goa should provide a way to specify custom Content-Type instead of forcing RFC 6848. There are applications which don't respect that (i.e., swagger-codegen is producing Java client which fails to decode response).

Currently there is no way to do that.

[raphael]

It's possible today by using the ContentType function in the design:

var BottleMedia = MediaType("application/vnd.foo", func() {
    ContentType("application/json")
    // ...
}

[dobegor]

Here is an example:

package design

import (
    . "github.com/goadesign/goa/design"
    . "github.com/goadesign/goa/design/apidsl"
)

var _ = API("test", func() {
    Title("test api")
    Scheme("http")
    Host("localhost:8080")
})

var Greeting = MediaType("application/vnd.greeting+json", func() {
    ContentType("application/json")
    Attributes(func() {
        Attribute("greeting", String, "greeting text")
    })

    View("default", func() {
        Attribute("greeting")
    })
})

var _ = Resource("hello", func() {
    BasePath("/hello")
    Action("hello", func() {
        Routing(GET("/"))
        Response(OK, Greeting)
    })
})

Controller:

// Hello runs the hello action.
func (c *HelloController) Hello(ctx *app.HelloHelloContext) error {
    // HelloController_Hello: start_implement

    // Put your logic here

    // HelloController_Hello: end_implement
    s := "hello world"
    res := &app.Greeting{
        Greeting: &s,
    }
    return ctx.OK(res)
}

Result: