Cannot display my rails 4 app in iframe even if 'X-Frame-Options' is 'ALLOWALL'

I am trying to test a responsive design. I am using Rails 4. I know it sets 'X-Frame-Options' to SAME ORIGIN. So I overrided it in development.rb using

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

and it worked. I checked out the network request in the Chrome console and it is as follows:

But still websites like and give me below error:

Refused to display 'http://localhost:3000/' in a frame because it set 'X-Frame-Options' to 'SAMEORIGIN'. about:blank:1

Whats going on??


I had the same problem as you, and searched for a solution to this problem all night.

I finally found out why it happens. It's because of the Chrome cache.

You can see the header['X-Frame-Options'] is ALLOWALL but it doesn't work.

Just try to open a "New Incognito Window" and go the same page and it works!

This problem only happened in development mode in my test. It worked fine in production mode.

Try just to delete this header 'X-Frame-Options'. Maybe this way in controller:

before_filter :allow_iframe_requests
def allow_iframe_requests

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"
To Allow a Specific Origin:
class MyController < ApplicationController
  def iframe_action
    response.headers["X-FRAME-OPTIONS"] = "ALLOW-FROM"

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

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

Use it in your controllers like this:

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

  def basic_embed

  def awesome_embed

  # Other Actions...

Do a Hard-Refresh in your browser, or use another browser to view changes

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

When 'Load denied by X-Frame-Options' using Heroku & Firefox

I had a similar issue where I kept getting this error only on Firefox. I had a PHP web page hosted @ MochaHost serving a Rails app hosted @ Heroku (so RoR app has a page with an iframe which is pointing to the PHP web page and this working on all browsers except on Firefox).

I was able to solve the problem by setting a default header for all of my requests in the specific environment file:

# config/enviroments/production.rb

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

Edit (as sheharyar suggested)

Ideally, you shouldn't set a default header and do this only for actions that have to be rendered in an iFrame. If your entire app is being served inside an iFrame, you should explicitly mention the Origin:

# config/enviroments/production.rb

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

Try ALLOW-FROM instead? ALLOWALL might be ok in Chrome if you have a sufficiently new version of Chrome [2]



If you want to have this change take effect in all environments, place it in application.rb.

I found another cause for this. Assuming the ALLOWALL or similar fix is implemented, the next gotcha is attempting to use http content in a https website which causes security risks and is blocked by mozilla, IE and probably other browsers. It took me 6 hours to identify this, hopefully by sharing I can reduce someones pain...

It can be checked by:

  • using your browser web-tools which should display an error.
  • web logs will lack any connection with your supplying site.
  • replace your contents url with a banks https home page should demonstrate the iframe otherwise works.

The solution is to ask the source if they have https content or find another supplier.


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