NAME
    Mojolicious::Plugin::OAuth2 - Auth against OAuth2 APIs

DESCRIPTION
    This Mojolicious plugin allows you to easily authenticate against a
    OAuth2 <http://oauth.net> provider. It includes configurations for a few
    popular providers, but you can add your own easily as well.

    Note that OAuth2 requires https, so you need to have the optional
    Mojolicious dependency required to support it. Run the command below to
    check if IO::Socket::SSL is installed.

       $ mojo version

  References
    *   <http://oauth.net/documentation/>

    *   <http://aaronparecki.com/articles/2012/07/29/1/oauth2-simplified>

    *   <http://homakov.blogspot.jp/2013/03/oauth1-oauth2-oauth.html>

    *   <http://en.wikipedia.org/wiki/OAuth#OAuth_2.0>

SYNOPSIS
  Example web application
      use Mojolicious::Lite;

      plugin "OAuth2" => {
        facebook => {
          key => "some-public-app-id",
          secret => $ENV{OAUTH2_FACEBOOK_SECRET},
        },
      };

      get "/connect" => sub {
        my $c = shift;
        $c->delay(
          sub {
            my $delay = shift;
            my $args = {redirect_uri => $c->url_for('connect')->userinfo(undef)->to_abs};
            $c->oauth2->get_token(facebook => $args, $delay->begin);
          },
          sub {
            my ($delay, $err, $data) = @_;
            return $c->render("connect", error => $err) unless $data->{access_token};
            return $c->session(token => $c->redirect_to('profile'));
          },
        );
      };

  Example blocking web application
      use Mojolicious::Lite;

      plugin "OAuth2" => {
        facebook => {
          key => "some-public-app-id",
          secret => $ENV{OAUTH2_FACEBOOK_SECRET},
        },
      };

      get "/connect" => sub {
        my $c = shift;
        my $args = {redirect_uri => $c->url_for('connect')->userinfo(undef)->to_abs};
        if (my $err = $c->param('error')) {
          # do stuff with error from OAuth2 provider
        } elsif (my $data = $c->oauth2->get_token(facebook => $args)) {
          # do stuff with $data->{access_token};
        } else {
          # already redirected by OAuth2 plugin
          return;
        }
      };

  Custom connect button
    You can add a "connect link" to your template using the
    "oauth2.auth_url" helper. Example template:

      Click here to log in:
      <%= link_to "Connect!", $c->oauth2->auth_url("facebook", scope => "user_about_me email") %>

  Configuration
    This plugin takes a hash as config, where the keys are provider names
    and the values are configuration for each provider. Here is a complete
    example:

      plugin "OAuth2" => {
        custom_provider => {
          key           => "APP_ID",
          secret        => "SECRET_KEY",
          authorize_url => "https://provider.example.com/auth",
          token_url     => "https://provider.example.com/token",
        },
      };

    To make it a bit easier, Mojolicious::Plugin::OAuth2 has already values
    for "authorize_url" and "token_url" for the following providers:

    *   dailymotion

        Authentication for Dailymotion video site.

    *   eventbrite

        Authentication for <https://www.eventbrite.com> event site.

        See also <http://developer.eventbrite.com/docs/auth/>.

    *   facebook

        OAuth2 for Facebook's graph API, <http://graph.facebook.com/>. You
        can find "key" (App ID) and "secret" (App Secret) from the app
        dashboard here: <https://developers.facebook.com/apps>.

        See also
        <https://developers.facebook.com/docs/reference/dialogs/oauth/>.

    *   github

        Authentication with Github.

        See also <https://developer.github.com/v3/oauth/>

    *   google

        OAuth2 for Google. You can find the "key" (CLIENT ID) and "secret"
        (CLIENT SECRET) from the app console here under "APIs & Auth" and
        "Credentials" in the menu at
        <https://console.developers.google.com/project>.

        See also <https://developers.google.com/+/quickstart/>.

  Testing
    THIS API IS EXPERIMENTAL AND CAN CHANGE WITHOUT NOTICE.

    To enable a "mocked" OAuth2 api, you need to give the special "mocked"
    provider a "key":

      plugin "OAuth2" => { mocked => {key => 42} };

    The code above will add two new routes to your application:

    *   GET /mocked/oauth/authorize

        This route is a web page which contains a link that takes you back
        to "redirect_uri", with a "code". The "code" default to "fake_code",
        but can be configured:

          $c->app->oauth2->providers->{mocked}{return_code} = "...";

        The route it self can also be customized:

          plugin "OAuth2" => { mocked => {authorize_url => '...'} };

    *   POST /mocked/oauth/token

        This route is will return a "access_token" which is available in
        your "oauth2.get_token" callback. The default is "fake_token", but
        it can be configured:

          $c->app->oauth2->providers->{mocked}{return_token} = "...";

        The route it self can also be customized:

          plugin "OAuth2" => { mocked => {token_url => '...'} };

HELPERS
  oauth2.auth_url
      $url = $c->oauth2->auth_url($provider => \%args);

    Returns a Mojo::URL object which contain the authorize URL. This is
    useful if you want to add the authorize URL as a link to your webpage
    instead of doing a redirect like "oauth2.get_token" does. %args is
    optional, but can contain:

    *   host

        Useful if your provider uses different hosts for accessing different
        accounts. The default is specified in the provider configuration.

          $url->host($host);

    *   authorize_query

        Either a hash-ref or an array-ref which can be used to give extra
        query params to the URL.

          $url->query($authorize_url);

    *   redirect_uri

        Useful if you want to go back to a different page than what you came
        from. The default is:

          $c->url_for->to_abs->to_string

    *   scope

        Scope to ask for credentials to. Should be a space separated list.

    *   state

        A string that will be sent to the identity provider. When the user
        returns from the identity provider, this exact same string will be
        carried with the user, as a GET parameter called "state" in the URL
        that the user will return to.

  oauth2.get_token
      $data = $c->oauth2->get_token($provider_name => \%args);
      $c    = $c->oauth2->get_token($provider_name => \%args, sub {
                my ($c, $err, $data) = @_;
              });

    "oauth2.get_token" is used to either fetch access token from OAuth2
    provider, handle errors or redirect to OAuth2 provider. This method can
    be called in either blocking or non-blocking mode. $err holds a error
    description if something went wrong. Blocking mode will "die($err)"
    instead of returning it to caller. $data is a hash-ref containing the
    access token from the OAauth2 provider. $data in blocking mode can also
    be "undef" if a redirect has been issued by this module.

    In more detail, this method will do one of two things:

    1.  If called from an action on your site, it will redirect you to the
        $provider_name's "authorize_url". This site will probably have some
        sort of "Connect" and "Reject" button, allowing the visitor to
        either connect your site with his/her profile on the OAuth2
        provider's page or not.

    2.  The OAuth2 provider will redirect the user back to your site after
        clicking the "Connect" or "Reject" button. $data will then contain a
        key "access_token" on "Connect" and a false value on "Reject" mode,
        or will die in blocking mode.

    Will redirect to the provider to allow for authorization, then fetch the
    token. The token gets provided as a parameter to the callback function.
    Usually you want to store the token in a session or similar to use for
    API requests. Supported arguments:

    *   host

        Useful if your provider uses different hosts for accessing different
        accounts. The default is specified in the provider configuration.

    *   scope

        Scope to ask for credentials to. Should be a space separated list.

  oauth2.providers
    This helper allow you to access the raw providers mapping, which looks
    something like this:

      {
        facebook => {
          authorize_url => "https://graph.facebook.com/oauth/authorize",
          token_url     => "https://graph.facebook.com/oauth/access_token",
          key           => ...,
          secret        => ...,
        },
        ...
      }

ATTRIBUTES
  providers
    Holds a hash of provider information. See oauth2.providers.

METHODS
  register
    Will register this plugin in your application. See "SYNOPSIS".

AUTHOR
    Marcus Ramberg - "mramberg@cpan.org"

    Jan Henning Thorsen - "jhthorsen@cpan.org"

LICENSE
    This software is licensed under the same terms as Perl itself.