How to set access-control-allow-origin in webrick under rails?

Question

I have written a small rails app to serve up content to another site via xmlhttprequests that will be operating from another domain (it will not be possible to get them runn

Answer 1

Rails 3.1 - using a controller after_filter did not work for me so I added a custom middleware instead:

In app/middleware/cors_middleware.rb:

# For icons to work in Firefox with CDN
class CorsMiddleware
  def initialize(app)
    @app = app
  end

  def call(env)
    status, headers, body = @app.call(env)
    cors_headers = headers.merge({
      'Access-Control-Allow-Origin' => '*',
      'Access-Control-Request-Method' => '*'        
    })
    [status, cors_headers, body]
  end  
end

In config/application.rb:

require File.join(Rails.root, "app", "middleware", "cors_middleware")
config.middleware.insert_before ActionDispatch::Static, CorsMiddleware # Need it early in the chain to work for assets

Answer 2

In case you want the solution as a Rack middleware gem: https://github.com/cyu/rack-cors

Answer 3

If you're on Rails 2 just add this to your application contoller.

before_filter :set_access

def set_access
  @response.headers["Access-Control-Allow-Origin"] = "*"
end

Obviously changing "*" to something a little less open would be a good idea.

Answer 4

Rails 3.1

class ApplicationController < ActionController::Base
  protect_from_forgery
  after_filter :set_access_control_headers

  def set_access_control_headers
    headers['Access-Control-Allow-Origin'] = '*'
    headers['Access-Control-Request-Method'] = '*'
  end
end

Answer 5

Rails 2.3.8

before_filter :allow_cross_domain_access
def allow_cross_domain_access
  response.headers["Access-Control-Allow-Origin"] = "*"
  response.headers["Access-Control-Allow-Methods"] = "*"
end

Answer 6

Rails 4 (http://edgeguides.rubyonrails.org/security.html#default-headers)

In config/application.rb:

config.action_dispatch.default_headers.merge!({
  'Access-Control-Allow-Origin' => '*',
  'Access-Control-Request-Method' => '*'
})