Ruby on Rails response_with和图像格式

Question

I have a controller that responds_to html and png ( I load the image dynamically and render it as text ). That makes the controller code messy and today I found respond_with, which looks very cool, but I can't found out how to make it work with formats, different than html, json and xml ( like the png )

I expected that this would work, but it stills tries to find a template file and ignores my method :(

models/user.rb

class User < ActiveRecord::Base  
  def to_png
    File.read("some_file.png")
  end
end

controllers/users_controller.rb

class UsersController < ApplicationController
  respond_to :html, :png

  # GET /users/1
  def show
    @user = User.find(params[:id])
    respond_with(@user)
  end
end

Answer 1

Try to add in file [YOUR_APP]/config/initializers/mime_types.rb :

Mime::Type.register "image/png", :png

and restart your application

Answer 2

if you need to use a MIME type which isn't supported by default, you can register your own handlers in environment.rb as follows.

Mime::Type.register "image/jpg", :jpg

http://apidock.com/rails/ActionController/MimeResponds/InstanceMethods/respond_to

in environment.rb

Mime::Type.register "image/png", :png

then

respond_to do |format|
   format.png do
      #do stuff here
   end
end

or

respond_with @user do |format|
   format.png do
      #do stuff here
   end
end