How can I pass parameters through an OAuth authentication so that my callback or controller can use?

Question

I am using OAuth to a provider (LinkedIn).

I want to be able to pass parameters so that when someone signs-up, I can add some additional values at the time the new User is created (I am using Devise).

But how do I do that?

It looks like the link goes to the provider, which then makes a callback to my application. How can I pass parameters from that link?

Answer 1

If you add GET style params to the authentication url they will be available in the callback via the Rails request.env object under the omniauth.params key. For example

If you authenticate via:

link_to "Log In", "/auth/linkedin?foo=bar"

In the controller method mapped to GET /auth/:provider/callback you will have:

request.env['omniauth.params'] == { "foo" => "bar" }

Answer was a bit late, but I hope it helps someone.

Answer 2

The easy way to do this is to set the parameters in the session, then access them in the callback.

In your action that redirects to the provider:

session[:additional] = additional_data_hash

In the action that handles the callback from the provider:

data = session.delete(:additional)

Use delete to ensure your session remains small for subsequent requests.