I need to pass some parameters to callback action. Judging from the source code, OmniAuth should add query string to callback URL but strangely it does not. When I open
/auth/facebook?from=partner
...and get redirected to Facebook, return_url is just
/auth/facebook/callback
...without any parameters.
OmniAuth already has a built-in way to know where the user was, it's called "origin" as documented here:
https://github.com/intridea/omniauth/wiki/Saving-User-Location
Use the 'state' Variable. Facebook allows the user to set a STATE variable.
Here is how I did it, I appended the AUTH URL with ?state=providername
http://localhost/users/auth/facebook?state=providername
This param is returned to me at Callback as params['providername']
I devised the solution from the original Omniauth Path Method
user_omniauth_authorize_path(:facebook, :display => 'page', :state=>'123') %>