Graph API Initialization

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In this tutorial, we will describe how to initialize Facebook Graph API and make initial code for getting data from Facebook. To ensure correct work of Facebook Graph API, be sure that you made all steps from Create Facebook Application and Install Facebook Connect PHP Toolkit tutorials correctly.



Initialization

This section is also listed in 'Install Facebook Connect PHP Toolkit', but it is repeated here to make this tutorial complete. Before using of any code from Facebook Graph API, it is required to include following code on each page immediately after <body> tag. It has taken in account that 'faceconn' folder is included in root folder of PHP application. 

<?php
require_once 'facebook.php';
require_once 'faceconn/faceconn.php';
UseGraphAPI();
?>


Create Facebook and Session objects

Every method call of Facebook Graph API is made using Facebook object. Before the call execution, it is required to get user object from Facebook object and check if it exists. User object will be set to null if user is not logged in. User can be logged on Facebook using Facebook Login Button. Here is a code to create the objects: 

// create facebook object.
$facebook = new Facebook(AppConfig::GetKeyArray());

// create facebook user object
$facebookUser = $facebook->getUser();

Example of using Graph API

This example shows how to get user object of logged user, by calling the Graph API, and then extract Facebook user id, first name and last name: 
if ($facebookUser) {
    // get user object
    $loggedUser = $facebook->api('/me');

    //extract data from user object
    $userId = $loggedUser['id'];
    $firstName = $loggedUser['first_name'];
    $lastName = $loggedUser['last_name'];
}
else
{
    echo "Error: Facebook Session does not exists. Please log in.";
}



Next: Using Graph API methods in PHP application


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