NAME

Net::Facebook::Oauth2 - a simple Perl wrapper around Facebook OAuth v2.0 protocol

FACEBOOK GRAPH API VERSION

This module complies to Facebook Graph API version 2.8, the latest at the time of publication, scheduled for deprecation on October 5th, 2018.

One month prior to that, using this version of Net::Facebook::Oauth2 will trigger a warning message.

SYNOPSIS

Somewhere in your application's login process:

use Net::Facebook::Oauth2;

my $fb = Net::Facebook::Oauth2->new(
    application_id     => 'your_application_id', 
    application_secret => 'your_application_secret',
    callback           => 'http://yourdomain.com/facebook/callback'
);

# get the authorization URL for your application
my $url = $fb->get_authorization_url(
    scope   => [ 'public_profile', 'email', 'user_about_me', 'manage_pages' ],
    display => 'page'
);

Now redirect the user to this $url.

Once the user authorizes your application, Facebook will send him/her back to your application, on the callback link provided above. PLEASE NOTE THAT YOU MUST PRE-AUTHORIZE YOUR CALLBACK URI ON FACEBOOK'S APP DASHBOARD.

Inside that callback route, use the verifier code parameter that Facebook sends to get the access token:

# param() below is a bogus function. Use whatever your web framework
# provides (e.g. $c->req->param('code'), $cgi->param('code'), etc)
my $code = param('code');

my $access_token = $fb->get_access_token(code => $code);

If you got so far, your user is logged! Save this access token in your database or session.

Later on you can use that access token to communicate with Facebook on behalf of this user:

my $fb = Net::Facebook::Oauth2->new(
    access_token => $access_token
);

my $info = $fb->get(
    'https://graph.facebook.com/v2.8/me'   # Facebook API URL
);

print $info->as_json;

DESCRIPTION

Net::Facebook::Oauth2 gives you a way to simply access FaceBook Oauth 2.0 protocol

For more information please see example folder shipped with this Module

SEE ALSO

For more information about Facebook Oauth 2.0 API

Please Check http://developers.facebook.com/docs/

get/post Facebook Graph API http://developers.facebook.com/docs/api

USAGE

Net::Facebook::Oauth->new( %args )

Returns a new object to handle user authentication. Pass arguments as a hash. The following arguments are REQUIRED unless you're passing an access_token (see optional arguments below):

• application_id

  Your application id as you get from facebook developers platform when you register your application

• application_secret

  Your application secret id as you get from facebook developers platform when you register your application

The following arguments are OPTIONAL:

• access_token

  If you want to instantiate an object to an existing access token, you may do so by passing it to this argument.

• browser

  The user agent that will handle requests to Facebook's API. Defaults to LWP::UserAgent, but can be any method that implements the methods get, post and delete and whose response to such methods implements is_success and content.

• display

  See display under the get_authorization_url method below.

• authorize_url

  Overrides the default (2.8) API endpoint for Facebook's oauth. Used mostly for testing new versions.

• access_token_url

  Overrides the default (2.8) API endpoint for Facebook's access token. Used mostly for testing new versions.

• auth_type

  When a user declines a given permission, you must reauthorize them. But when you do so, any previously declined permissions will not be asked again by Facebook. Set this argument to 'rerequest' to explicitly tell the dialog you're re-asking for a declined permission.

$fb->get_authorization_url( %args )

Returns an authorization URL for your application. Once you receive this URL, redirect your user there in order to authorize your application.

The following argument is REQUIRED:

• callback

  callback => 'http://example.com/login/facebook/success'

  The callback URL, where Facebook will send users after they authorize your application. YOU MUST CONFIRM THIS URL ON FACEBOOK'S APP DASHBOARD.

  To do that, go to the App Dashboard, click Facebook Login in the right-hand menu, and check the Valid OAuth redirect URIs in the Client OAuth Settings section.

This method also accepts the following OPTIONAL arguments:

• scope

  scope => ['user_events','manage_pages', ...]

  Array of Extended permissions as described by facebook Oauth API. You can get more information about scope/Extended Permission from

  https://developers.facebook.com/docs/facebook-login/permissions/

  Please note that requesting information other than public_profile, email and user_friends will require your app to be reviewed by Facebook!

• state

  state => '123456abcde'

  An arbitrary unique string provided by you to guard against Cross-site Request Forgery.

• display

  display => 'page'

  How to display Facebook Authorization page. Defaults to page. Can be any of the following:

  • page

    This will display facebook authorization page as full page

  • popup

    This option is useful if you want to popup authorization page as this option tell facebook to reduce the size of the authorization page

  • wab

    From the name, for wab and mobile applications this option is the best facebook authorization page will fit there :)

• response_type

  response_type => 'code'

  When the redirect back to the app occurs, determines whether the response data is in URL parameters or fragments. Defaults to code, which is Facebook's default and useful for cases where the server handles the token (which is most likely why you are using this module), but can be also be token, code%20token, or granted_scopes. Please see Facebook's login documentation for more information.

$fb->get_access_token( %args )

This method issues a GET request to Facebook's API to retrieve the access token string for the specified code (passed as an argument).

Returns the access token string or raises an exception in case of errors.

You should call this method inside the route for the callback URI defined in the get_authorization_url method. It receives the following arguments:

• code

  This is the verifier code that Facebook sends back to your callback URL once user authorize your app, you need to capture this code and pass to this method in order to get the access token.

  Verifier code will be presented with your callback URL as code parameter as the following:

  http://your-call-back-url.com?code=234er7y6fdgjdssgfsd...

  Note that if you have fiddled with the response_type argument, you might not get this parameter properly.

When the access token is returned you need to save it in a secure place in order to use it later in your application. The token indicates that a user has authorized your site/app, meaning you can associate that token to that user and issue API requests to Facebook on their behalf.

To know WHICH user has granted you the authorization (e.g. when building a login system to associate that token with a unique user on your database), you must make a request to fetch Facebook's own unique identifier for that user, and then associate your own user's unique id to Facebook's. This is usually done by making a GET request to the me API endpoint, as shown in the SYNOPSIS.

IMPORTANT: Expect that the length of all access token types will change over time as Facebook makes changes to what is stored in them and how they are encoded. You can expect that they will grow and shrink over time. Please use a variable length data type without a specific maximum size to store access tokens.

$fb->get( $url, $args )

Sends a GET request to Facebook and stores the response in the given object.

• url

  Facebook Graph API URL as string. You must provide the full URL.

• $args

  hashref of parameters to be sent with graph API URL if required.

You can access the response using the following methods:

• $response>as_json

  Returns response as json object

• $response>as_hash

  Returns response as perl hashref

For more information about facebook graph API, please check http://developers.facebook.com/docs/api

$fb->post( $url, $args )

Send a POST request to Facebook and stores the response in the given object. See the as_hash and as_json methods above for how to retrieve the response.

• url

  Facebook Graph API URL as string

• $args

  hashref of parameters to be sent with graph API URL

For more information about facebook graph API, please check http://developers.facebook.com/docs/api

$fb->delete( $url, $args )

Send a DELETE request to Facebook and stores the response in the given object. See the as_hash and as_json methods above for how to retrieve the response.

• url

  Facebook Graph API URL as string

• $args

  hashref of parameters to be sent with graph API URL

AUTHOR

Mahmoud A. Mehyar, <mamod.mehyar@gmail.com>

CONTRIBUTORS

Big Thanks To

• Takatsugu Shigeta @comewalk

• Breno G. de Oliveira @garu

• squinker @squinker

• Valcho Nedelchev @valchonedelchev

COPYRIGHT AND LICENSE

Copyright (C) 2012-2016 by Mahmoud A. Mehyar

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.1 or, at your option, any later version of Perl 5 you may have available.

cpanm Net::Facebook::Oauth2

perl -MCPAN -e shell
install Net::Facebook::Oauth2