How to enable CORS in Rails 4 App

Question

I\'m just about to pull my hair out... I\'ve been trying to enable CORS in this Rails app since the morning and it just doesn\'t work. I\'ve tried this, using Rack Cors Gem

Answer 1

You should use rack cors

It provides a nice DSL, to use in your config/application.rb, instead of the messy header work and before filters.

A very permissive would be as follows, but of course, you'll have to tailor it a bit.

use Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: :any
  end  
end

Answer 2

Rack::Cors provides support for Cross-Origin Resource Sharing

Steps to enable rackcors :

1.add gem to your Gemfile:

gem 'rack-cors'

2.Add below code to config/application.rb

# if you are using Rails 3/4
config.middleware.insert_before 0, "Rack::Cors" do
  allow do
    origins '*'
    resource '*', :headers => :any, :methods => :any
  end
end
# if you are using Rails 5

config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: :any
  end
end

Answer 3

Here's what worked for me:

1. Add this to Gemfile: gem 'rack-cors' then bundle install

2. Create a new file /config/initializers/cors.rb

3. Inside the file place the following:

Rails.application.config.middleware.insert_before 0, Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: [:get, :post, :patch, :put]
  end
end

That's it!

FYI the instructions came directly from here