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OmniAuth CAS Strategy Gem Version Build Status

omniauth-cas now has a maintainer please use it instead

This is a OmniAuth 1.0 compatible port of the previously available OmniAuth CAS strategy that was bundled with OmniAuth 0.3. This strategy has also been updated for CAS protocol version 3.0 and patched to deal with namespace issues.


Add this line to your application's Gemfile:

gem 'omniauth-cas3'

And then execute:

$ bundle

Or install it yourself as:

$ gem install omniauth-cas3


Use like any other OmniAuth strategy:

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :cas3, host: ''

Configuration Options


OmniAuth CAS requires at least one of the following two configuration options:

  • url - Defines the URL of your CAS server (i.e.
  • host - Defines the host of your CAS server (i.e.


Other configuration options:

  • port - The port to use for your configured CAS host. Optional if using url.

  • ssl - TRUE to connect to your CAS server over SSL. Optional if using url.

  • service_validate_url - The URL to use to validate a user. Defaults to '/serviceValidate'.

  • callback_url - The URL custom URL path which CAS uses to call back to the service. Defaults to /users/auth/cas3/callback.

  • logout_url - The URL to use to logout a user. Defaults to '/logout'.

  • login_url - Defines the URL used to prompt users for their login information. Defaults to /login If no host is configured, the host application's domain will be used.

  • uid_field - The user data attribute to use as your user's unique identifier. Defaults to 'user' (which usually contains the user's login name).

  • ca_path - Optional when ssl is true. Sets path of a CA certification directory. See Net::HTTP for more details.

  • disable_ssl_verification - Optional when ssl is true. Disables verification.

  • merge_multivalued_attributes - When set to true returns attributes with multiple values as arrays. Defaults to false and returns the last value as a string.

  • on_single_sign_out - Optional. Callback used when a CAS 3.1 Single Sign Out request is received.

  • fetch_raw_info - Optional. Callback used to return additional "raw" user info from other sources.

    provider :cas3,
      fetch_raw_info: { |strategy, opts, ticket, user_info, rawxml|
        return {} if user_info.empty? || rawxml.nil? # Auth failed
        extra_info = ExternalService.get(user_info[:user]).attributes
        extra_info.merge!({'roles' => rawxml.xpath('//cas:roles').map(&:text)})

Configurable options for values returned by CAS:

  • uid_key - The user ID data attribute to use as your user's unique identifier. Defaults to 'user' (which usually contains the user's login name).
  • name_key - The data attribute containing user first and last name. Defaults to 'name'.
  • email_key - The data attribute containing user email address. Defaults to 'email'.
  • nickname_key - The data attribute containing user's nickname. Defaults to 'user'.
  • first_name_key - The data attribute containing user first name. Defaults to 'first_name'.
  • last_name_key - The data attribute containing user last name. Defaults to 'last_name'.
  • location_key - The data attribute containing user location/address. Defaults to 'location'.
  • image_key - The data attribute containing user image/picture. Defaults to 'image'.
  • phone_key - The data attribute containing user contact phone number. Defaults to 'phone'.

Migrating from OmniAuth 0.3

Given the following OmniAuth 0.3 configuration:

provider :CAS, cas_server: ''

Your new settings should look similar to this:

provider :cas3,
         host:      '',
         login_url: '/cas/login',
  	     service_validate_url: '/cas/p3/serviceValidate'

If you encounter problems with SSL certificates you may want to set the ca_path parameter or activate disable_ssl_verification (not recommended).


  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Added some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request


Special thanks go out to the following people

  • @dlindahl For the original work in porting this from OmniAuth 0.3
  • Phillip Aldridge (@iterateNZ) and JB Barth (@jbbarth) for helping out with Issue #3
  • Elber Ribeiro (@dynaum) for Ubuntu SSL configuration support
  • @rbq for README updates and OmniAuth 0.3 migration guide


A CAS OmniAuth Strategy







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