Overriding Content-Type for Input & Output and Content Negotiation issues

[k0ality]

Hi!

My application uses "application/vnd.api+json" Content-Type, so I've specified this in huma Config accordingly:

huma.Config{
    OpenAPI: &huma.OpenAPI{
			OpenAPI: "3.1.0",
			...
		Formats: map[string]huma.Format{
			"application/vnd.api+json": huma.DefaultJSONFormat,
			"application/problem+json": huma.DefaultJSONFormat,
		},
		DefaultFormat: "application/vnd.api+json",
	}

I've also added

ContentType string `header:"Content-Type" example:"application/vnd.api+json"`

to my Input and Output structs.
And couldn't find an Operation level way to specify Content-Type.

However, in generated documentation I always get:

responses:
        "200":
          content:
            application/json:
              schema:
...

as well in UI "application/json" and ONLY "application/json" is offered in Body dropdown and selected by default, which results in HTTP 415 Unsupported Media Type.

Is there a way to override this? Is it hardcoded in Stoplight Elements?

[k0ality]

Further digging lead me to next discoveries:

to change Input content type and get this documentation:

requestBody:
        content:
          application/vnd.api+json:
            schema:
              $ref: "#/components/schemas/MyThingInputBody"
        required: true

you need to specify contentType as struct tag, not header
https://huma.rocks/features/request-inputs/?h=#request-body

Right way:

type MyThingInput struct {
	Authorization string `header:"x-api-key" required:"true"`
	Uid string `path:"uid"`
	Body struct {
		_     struct{} `json:"-" additionalProperties:"true"`
	} `contentType:"application/vnd.api+json"`
}

Wrong way:

type MyThingInput struct {
        ContentType string `header:"Content-Type" example:"application/vnd.api+json"`
	Authorization string `header:"x-username" required:"true"`
	Uid string `path:"uid"`
	Body struct {
		_     struct{} `json:"-" additionalProperties:"true"`
	}
}

For Output content type the only way I've found is specifying Response on Operation level (instead of in Output struct) - which looks cumbersome to me, but does the thing. Example:

huma.Register(api, huma.Operation{
		Method:      http.MethodPost,
		Path:        "/thing/{uid}",
		OperationID: "thing-create",
		Summary:     "Create Thing",
		Tags:        []string{"Thing"},
		Responses: map[string]*huma.Response{
			"200": {
				Content: map[string]*huma.MediaType{
					"application/vnd.api+json": {
						Schema: api.OpenAPI().Components.Schemas.Schema(reflect.TypeOf(MyThingInput{}), true, ""),
					},
				},
			},
		},
	}, thingHandler.Create)

generates documentation

responses:
        "200":
          content:
            application/vnd.api+json:
              schema:
                $ref: "#/components/schemas/ThingResource"
          description: OK

This also magically changes Accept header used in docs (Stoplight UI) under the hood.

---

However after all this manipulations my content negotiation is broken despite sending correct headers and having all required formats in Huma config:

Formats: map[string]huma.Format{
	"application/vnd.api+json": huma.DefaultJSONFormat,
	"application/problem+json": huma.DefaultJSONFormat,
	"application/json": huma.DefaultJSONFormat,
},
DefaultFormat: "application/vnd.api+json",

So I still can't use my custom content type consistently and get correct documentation.
I get HTTP 415 "unknown content type: application/vnd.api+json" error

[k0ality]

Couldn't resolve content negotiation problem, had to create an issue - #833