NAME

    Dancer2::Plugin::Auth::OAuth - OAuth for your Dancer2 app

SYNOPSIS

      # just 'use' the plugin, that's all.
      use Dancer2::Plugin::Auth::OAuth;

DESCRIPTION

    Dancer2::Plugin::Auth::OAuth is a Dancer2 plugin which tries to make
    OAuth authentication easy.

    The module is highly influenced by Plack::Middleware::OAuth and Dancer
    1 OAuth modules, but unlike the Dancer 1 versions, this plugin only
    needs configuration (look mom, no code needed!). It automatically sets
    up the needed routes (defaults to /auth/$provider and
    /auth/$provider/callback). So if you define the Twitter provider in
    your config, you should automatically get /auth/twitter and
    /auth/twitter/callback.

    After a successful OAuth dance, the user info is stored in the session
    "oauth". What you do with it afterwards is up to you. Please note the
    user will continue to be authenticated until the Dancer2 session has
    expired, whenever that might be.

CONFIGURATION

    The plugin comes with support for Facebook, Google, Twitter, GitHub,
    Stack Exchange, LinkedIn and several more (other providers aren't hard
    to add, send me a pull request when you add more!).

    All it takes to use OAuth authentication for a given provider, is to
    add the configuration for it. You don't need anything else.

    The YAML below shows all available options.

      plugins:
        "Auth::OAuth":
          reauth_on_refresh_fail: 0 [*]
          prefix: /auth [*]
          success_url: / [*]
          error_url: / [*]
          providers:
            Facebook:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
              fields: id,email,name,gender,picture
              # Original default Facebook scope was 'email,public_profile,user_friends'
              # Since March 2018 'user_friends' requires an app review.
              # Add the following three lines if you don't have it reviewed.
              query_params:
                authorize:
                  scope: email,public_profile
            Google:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
            AzureAD:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
            Twitter:
              tokens:
                consumer_key: your_consumer_token
                consumer_secret: your_consumer_secret
            Github:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
            Stackexchange:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
                key: your_key
              site: stackoverflow
            Linkedin:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
              fields: id,num-connections,picture-url,email-address
            VKontakte: # https://vk.com
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
              fields: 'first_name,last_name,about,bdate,city,country,photo_max_orig,sex,site'
              api_version: '5.8'
            Odnoklassniki: # https://ok.ru
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
                application_key: your_application_key
              method: 'users.getCurrentUser'
              format: 'json'
              fields: 'email,name,gender,birthday,location,uid,pic_full'
            MailRU:
              tokens:
                client_id: your_client_id
                client_private: your_client_private
                client_secret: your_client_secret
              method: 'users.getInfo'
              format: 'json'
              secure: 1
            Yandex:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret
              format: 'json'
            SalesForce:
              tokens:
                client_id: your_client_id
                client_secret: your_client_secret

    [*] default value, may be omitted.

 FUNCTIONAL LOGIN

    The main purpose of this module is simply to authenticate against a
    third party Identity Provider (IdP).

    However you can get a bit more than that.

    Your Dancer2 app might additionally use the "id_token" to access the
    API of the same (or other) third parties to enable you to do cool stuff
    with your apps, like show a feed, access data, etc.

    Because access to the third party systems would be cut off when the
    "id_token" expires, Dancer2::Plugin::Auth::OAuth will automatically set
    up the route /auth/$provider/refresh. Call this when the token has
    expired to try to refresh the token without bumping the user back to
    log in. You can optionally tell Dancer2::Plugin::Auth::OAuth to bump
    the user back to the login page if for whatever reason the refresh
    fails.

    In addition, Dancer2::Plugin::Auth::OAuth will save or generate an auth
    session key called "expires", which is (usually) number of seconds from
    epoch. Check this to determine if the "id_token" has expired (see
    examples below).

    Authenticate using one of the examples below but be sure to use the
    'refresh' functionality, as the logged in user will need to have a
    valid "id_token" at all times.

    Also make sure that you set the scope of your authentication to tell
    the third party what you wish to access (and for Microsoft/Azure also
    set the resource, for the same reason).

    Once you've got an active session you can get the "id_token" to use in
    further calls to the providers backend systems with:

      my $session_data = session->read('oauth');
      my $token = $session_data->{$provider}{id_token};

SETTING THE SCOPE

    If you're authenticating in order to use the "id_token" issued, or if
    login requires a specific 'scope' setting, you can change these values
    in the initial calls like this within your YAML config (example
    provided for AzureAD plugin).

      Auth::OAuth:
        providers:
          AzureAD:
            query_params:
              authorize:
                scope: 'Calendars.ReadWrite Contacts.Read Directory.Read.All Files.Read.All Group.Read.All GroupMember.Read.All Mail.ReadWrite openid People.Read Sites.Read.All Sites.ReadWrite.All User.Read User.ReadBasic.All Files.Read.All'

    You do not need to list all other authorize attributes sent to the
    server, unless you want to change them from the default values set in
    the provider. Please view the provider source/documentation for what
    these default values are.

    You may also need to set a value for "resource" in the same way. Refer
    to your providers OAuth documentation.

AUTHENTICATION EXAMPLES

    The response from the IdP is stored as a hash in the session with key
    "oauth". An example of a Facebook response:

        {
            facebook   {
                access_token   "...",
                expires        1662472004,
                expires_in     5183933,
                issued_at      1657288071,
                token_type     "bearer",
                user_info      {
                    email                "someone@example.com",
                    id                   12345678901234567,
                    name                 "José do Telhado",
                    picture              {
                        data   {
                            height          50,
                            is_silhouette   0,
                            url             "https://platform-lookaside.fbsbx.com/platform/profilepic/...",
                            width           50
                        }
                    },
                }
            }
        }

    Full site needs a user authentication for a specific IdP.

      An example of a simple single system authentication.

          hook before => sub {
              my $session_data = session->read('oauth');
              my $provider = "facebook"; # Lower case of the authentication plugin used
      
              if ((!defined $session_data || !defined $session_data->{$provider} || !defined $session_data->{$provider}{id_token}) && request->path !~ m{^/auth}) {
                return forward "/auth/$provider";
              }
          };

      If you want to be sure they have a valid "id_token" at all times:

          hook before => sub {
              my $session_data = session->read('oauth');
              my $provider = "facebook"; # Lower case of the authentication plugin used
      
              my $now = DateTime->now->epoch;
      
              if ((!defined $session_data || !defined $session_data->{$provider} || !defined $session_data->{$provider}{id_token}) && request->path !~ m{^/auth}) {
                return forward '/auth/$provider';
      
              } elsif (defined $session_data->{$provider}{refresh_token} && defined $session_data->{$provider}{expires} && $session_data->{$provider}{expires} < $now && request->path !~ m{^/auth}) {
                return forward "/auth/$provider/refresh";
      
              }
          };

      in the case where you're using the refresh functionality, a failure
      of the refresh will send the user back to the "error_url". If you
      want to them to instead be directed back to the main authentication
      (log in page) then please set the configuration option
      reauth_on_refresh_fail.

      If the provider(s) you are using don't have the "id_token" change the
      example accordingly.

    Site has a mix of public zones and private or needing use
    authentication

      1. You only use one provider

          get '/we/need/a/user/here' => sub {
              my $session_data = session->read('oauth');
              my $provider = "facebook";
      
              redirect '/auth/$provider' unless $session_data && defined $session_data->{$provider};
      
              ...
          }

      2. You also have a login page to choose from a list of providers
      accepted by the site

      You may update the configuration file:

          "Auth::OAuth":
              success_url: /login/ok
              error_url: /login/fail

      And on your code

          get '/we/need/a/user/here' => sub {
              my $session_data = session->read('oauth');
      
              redirect '/login' unless $session_data;
      
              ...
          }
      
          get '/login/ok' => sub {
              my $session_data = session->read('oauth');
      
              redirect '/login' unless $session_data;
      
              # Do something with the user data, update DB,
              # update session, etc
      
          }

      The login page can just have a list of the providers with a link to
      "/auth/<lc-name-of-the-provider>"

      You can mix this plugin with Dancer2::Plugin::Auth::Tiny and on
      '/login/ok' you just define the 'user' session. Afterwards all
      validation can be against 'user' and not 'oauth'.

AUTHOR

    Menno Blom <blom@cpan.org>

COPYRIGHT

    Copyright 2014- Menno Blom

LICENSE

    This library is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.