customHandler.go

type AppResponse struct {
	Error   error       `json:"-"`
	Code    int         `json:"code,omitempty"`
	Message string      `json:"message,omitempty"`
	Data    interface{} `json:"data,omitempty"`
}

type apiHandler func(w http.ResponseWriter, r *http.Request) AppResponse

func (handler apiHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	result := handler(w, r)

	if result.Error != nil {
		result.Message = result.Error.Error()
		render.JSON(w, http.StatusInternalServerError, result)
	} else {
		render.JSON(w, http.StatusOK, result)
	}
}

func someHandler(w http.ResponseWriter, r *http.Request) AppResponse {
	// Then we can simply return anywhere...
	// This would be for a CREATE that needs no data in the response.
	return AppResponse{
		Message: "ok",
	}	
}