Can't Get Rack-Cors Working in Rails Application

Can't get rack-cors working in rails application

I ran into the same problem with heroku. I found this blog with the same rack-cors issue.

Just moved the use Rack::Cors to config.ru, redeployed to heroku and it works.

require ::File.expand_path('../config/environment',  __FILE__)
run Rails.application

require 'rack/cors'
use Rack::Cors do

  # allow all origins in development
  allow do
    origins '*'
    resource '*', 
        :headers => :any, 
        :methods => [:get, :post, :delete, :put, :options]
  end
end

How to test if Rails rack-cors gem is working

To test CORS locally, I found this repo: https://github.com/njgibbon/nicks-cors-test

Just clone it, and click on the html file so it opens in your browser. By default it is calling the github API (https://api.github.com) and fetching info from there. You can open the console and check it.
If you change it to https://google.com it will throw a CORS restriction.

Similarly, you can change it to http://localhost:3000/api/v1/users (in my case) and it will throw a CORS error with the config I have now.

To double-check, just go to cors.rb and put origins "*". Restart the app server and try running again the html file. Now we won't be blocked.

Can't install rake-cors in rails-api app

I don't think rack-cors would create a initializer. If you followed the README on Github, you have to do it yourself. Put this snippet of code into your application.rb file.

module YourApp
  class Application < Rails::Application

    # ...

    config.middleware.insert_before 0, "Rack::Cors" do
      allow do
        origins '*'
        resource '*', :headers => :any, :methods => [:get, :post, :options]
      end
    end

  end
end

There is not an initializer in the example app as well.

gem rack-cors not working and request from angular client to rails api throwing cors error

It turns out I need to change how protect_from_forgery was handled as mentioned in docs

protect_from_forgery with: :null_session

PS: To the person who deleted his answer, please don't do that, knowing what not to do is also part of leaning.

Heroku, Rails 4, and Rack::Cors

It looks like the issue is being caused by my machine or the network I am on. I SSHed into a hosting environment I use and used the curl command above and it worked.

Additional Note
Here is something else that just happened that I thought I ought to add to this. My AJAX request was not to the https URL for my Heroku app, but Heroku was translating it be https. This was causing an additional cross-origin issue. Switching to use https for the AJAX request fixed this.

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