Ruby on rails 4 app does not work in iframe

How can I embed my rails app into another website via iframe?

It works nicely with RoR 3, but not with RoR 4:

<iframe src="http://myrailsapp.com/" width="100%" height="50" id="rails_iframe">error!</iframe>

I tried to use verify_authenticity_token and protect_from_forgery options in my controller... seems it's something else (but I'm not sure).

upd. Example: http://jsfiddle.net/zP329/

This has to do with Rails 4 enabling additional security protocols by default: http://weblog.rubyonrails.org/2013/2/25/Rails-4-0-beta1/

The setting that breaks iFrames on remote sites is X-Frame-Options. By default, this is set to SAMEORIGIN, which prevents the content from being loading cross domain:

config.action_dispatch.default_headers = {
    'X-Frame-Options' => 'SAMEORIGIN'
}

You can read about the new default headers here: http://edgeguides.rubyonrails.org/security.html#default-headers

In order to allow the iFrame to work cross domain, you can change the default headers to allow X-Frame across domain.

config.action_dispatch.default_headers = {
    'X-Frame-Options' => 'ALLOWALL'
}

Rails 4 added a default X-Frame-Options HTTP header value of SAMEORIGIN. This is good for security, but when you do want your action to be called in an iframe, you can do this:

---

To Allow all Origins:

class MyController < ApplicationController
  def iframe_action
    response.headers.delete "X-Frame-Options"
    render_something
  end
end

To Allow a Specific Origin:

class MyController < ApplicationController
  def iframe_action
    response.headers["X-FRAME-OPTIONS"] = "ALLOW-FROM http://some-origin.com"
    render_something
  end
end

---

Use :after_filter

When you need to use more than one of your action in an iframe, it's a good idea to make a method and call it with :after_filter:

class ApplicationController < ActionController::Base

  private
  def allow_iframe
    response.headers.delete "X-Frame-Options"
  end
end

Use it in your controllers like this:

class MyController < ApplicationController
  after_filter :allow_iframe, only: [:basic_embed, :awesome_embed]

  def basic_embed
      render_something
  end

  def awesome_embed
      render_something
  end

  # Other Actions...
end

---

Via: Rails 4: let specific actions be embedded as iframes

Update: seems like ALLOW-FROM and ALLOWALL are currently both invalid "X-Frame-Options" header values. The only two valid ones are DENY and SAMEORIGIN and neither allows access from another origin. See MDN documentation: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options.

So looks like response.headers.delete "X-Frame-Options" is the only way now to enable displaying content in an iframe on another site. But I'd love to be proven otherwise if anyone has any knowledge I don't.

I'm working with Rails 6 and Chromium 76. Previous solution with X-Frame-Options is not working. But I've noticed that it works very well when we attach online iframe with JS. So, I just made this simple solution in my view:

<div id='iframe_wrapper' 'data-iframe-content'='<iframe src="https://host.com/"></iframe>'>
</div>

...and add JS code like this:

$(document).ready(function() {
  var wrapper = $('#iframe_wrapper')[0]
  wrapper.innerHTML = wrapper.attributes['data-iframe-content'].value
})