How to Execute Login With Facebook Account Using PHP

This is another contribution to creating a social login in PHP. In this post we use the Facebook account login to give the user access to our website. Here you can find the registration process for the Facebook PHP SDK library. In this tutorial we used the latest Facebook API SDK library to log in with PHP script.

Most websites usually have the registration form to register and access the website. However, the majority of users are not interested in filling out the registration form for large websites. If you have allowed the user to log in or register with the Facebook login, the user does not currently have to fill out a large registration form and can easily access the website by logging in with a Facebook account. In this blog you will learn how to implement the login with the Facebook account on your PHP website.

Here we used the Facebook PHP SDK library, which you can use to access the Facebook API from your PHP web application. With this library you can easily integrate PHP login with the Facebook account via the Facebook SDK library. Here you can find out how to use Facebook to switch the user login and registration system to PHP and display the user profile data on the website.

Now we have started with the latest version of Facebook SDK v5.x and your system should require the following configuration.

• The PHP version must be greater than 5.4.
• The mbstring extension must be activated on your server.

Create Facebook Application

To get access to the Facebook API, you first need to create the Facebook application and then get the application ID and secret App that you can use when calling the Facebook API. Below is a step-by-step guide to creating a Facebook application in the Facebook developer area.

1. First go to the developer page https://developers.facebook.com/ Facebook and log in with your Facebook account. 



2. After logging in to Facebook, click the My Applications menu and then click the Create Application link.



3. After clicking the Create Application link, Modal will appear on the website. Here you need to define the details of the display name of the application and click on the Create Application ID button.




4. Now navigate to Settings » Base link.



5. Here you have to enter the domains of the applications, the URL of the privacy policy and the URL of the terms of use and select the category. Finally, you need to click the Save Changes button.



6. Now you need to navigate to the Add Product page by clicking the plus sign. Then appears modal and here you have to select website.



7. After selecting the Website option, the Website field on the website is displayed. Here you have to define the URL of your application site.



8. Now you need to add a product, go to the Link Dashboard and set up the Facebook login product.



9. After you have configured the Facebook login product, a new website has been loaded. Here you need to define the valid OAuth forwarding URIs and click the Save Changes button.



10. You have changed your status from development mode to live mode. To do this, you must click the Deactivate button. After clicking the Deactivate button, the modal is displayed. Here you have to select category and click on the Change Mode button. After you click the Change Mode button, your application goes live. This is necessary in order to retrieve profile data from the Facebook API.

Download Facebook SDK for PHP

Then we want to download the Facebook SDK for the PHP library. To do this, we need to open the Command Prompt Editor. In this first step, you need to go to the directory where you want to download the Facebook SDK for PHP. After that, you need to run the Composer command since we used the Composer dependency manager to download the Facebook SDK for PHP. After that, you need to run the following command

composer require facebook/graph-sdk

This command downloads the Facebook SDK library for PHP in the definition directory.

config.php

In this file, we first need to add the autoload.php file from the Facebook SDK library for PHP using the require_once statement.

Then we have to check whether the session variable was started with the PHP function session_id () or not.

Now we need to call the Facebook API, here we need to define the app_id and app_secret key that we need to get when building the Facebook application. Here we also have to define default_graph_version.

<?php

require_once 'vendor/autoload.php';

if (!session_id())
{
    session_start();
}

// Call Facebook API

$facebook = new \Facebook\Facebook([
  'app_id'      => '921130358246916',
  'app_secret'     => '8d382dc63a190925664594ef090b8a78',
  'default_graph_version'  => 'v2.10'
]);

?>

index.php

In this file, we must first add the config.php file with the include statement.

After that we would like help with the redirection of the login. Here we used the getRedirectLoginHelper () method.



Now we want to check whether a variable value $ _GET ['code'] was received or not. If it is received, it means that the user has logged Suppose you got the value of the $ _GET ['code'] variable. Then we would like to check whether the access token was stored in the $ _SESSION variable or not. If it is already stored in the $ _SESSION variable, this value is saved in the local variable.

Assume that the access token is not retrieved from the $ _SESSION variable. Then you have to get it with the getAccessToken () method and save it in the local variable and then in the variable $ _SESSION.

Now that we have received the access token, we want to set the default access token to be used for the request with the setDefaultAccessToken () method.

Now we have retrieved profile data using the get () method and under this method we have to define profile fields like name, email etc. and in the second argument we have to define the value of the access token.


To get user profile data, we used getGraphUser () here. This method creates a graphical collection of users.

In this way we can retrieve data from the Facebook API and save it in the variable $ _SESSION.

To create a link to log in with a Facebook account, we have the getLoginUrl () method here. This method sends the user to log in to Facebook. With this method you have to define the forwarding URL and the authorization matrix.

For this reason, you can call up the source code to log in to Facebook with PHP and display the profile data on the website.

<?php

//index.php

include('config.php');

$facebook_output = '';

$facebook_helper = $facebook->getRedirectLoginHelper();

if(isset($_GET['code']))
{
 if(isset($_SESSION['access_token']))
 {
  $access_token = $_SESSION['access_token'];
 }
 else
 {
  $access_token = $facebook_helper->getAccessToken();

  $_SESSION['access_token'] = $access_token;

  $facebook->setDefaultAccessToken($_SESSION['access_token']);
 }

 $_SESSION['user_id'] = '';
 $_SESSION['user_name'] = '';
 $_SESSION['user_email_address'] = '';
 $_SESSION['user_image'] = '';

 $graph_response = $facebook->get("/me?fields=name,email", $access_token);

 $facebook_user_info = $graph_response->getGraphUser();

 if(!empty($facebook_user_info['id']))
 {
  $_SESSION['user_image'] = 'http://graph.facebook.com/'.$facebook_user_info['id'].'/picture';
 }

 if(!empty($facebook_user_info['name']))
 {
  $_SESSION['user_name'] = $facebook_user_info['name'];
 }

 if(!empty($facebook_user_info['email']))
 {
  $_SESSION['user_email_address'] = $facebook_user_info['email'];
 }
 
}
else
{
 // Get login url
    $facebook_permissions = ['email']; // Optional permissions

    $facebook_login_url = $facebook_helper->getLoginUrl('https://greenhouses-pro.co.uk/demo/', $facebook_permissions);
    
    // Render Facebook login button
    $facebook_login_url = '<div align="center"><a href="'.$facebook_login_url.'"><img src="php-login-with-facebook.gif" /></a></div>';
}



?>
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>How to Execute  Login With Facebook Account Using PHP</title>
  <meta content='width=device-width, initial-scale=1, maximum-scale=1' name='viewport'/>
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
  <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" />
  
 </head>
 <body>
  <div class="container">
   <br />
   <h2 align="center">How to Execute  Login With Facebook Account Using PHP</h2>
   <br />
   <div class="panel panel-default">
    <?php 
    if(isset($facebook_login_url))
    {
     echo $facebook_login_url;
    }
    else
    {
     echo '<div class="panel-heading">Welcome User</div><div class="panel-body">';
     echo '<img src="'.$_SESSION["user_image"].'" class="img-responsive img-circle img-thumbnail" />';
     echo '<h3><b>Name :</b> '.$_SESSION['user_name'].'</h3>';
     echo '<h3><b>Email :</b> '.$_SESSION['user_email_address'].'</h3>';
     echo '<h3><a href="logout.php">Logout</h3></div>';
    }
    ?>
   </div>
  </div>
 </body>
</html>

logout.php

<?php

//logout.php

session_destroy();

header('location:index.php');

?>

In this post, you will learn how to allow the user to log in to the PHP website using a Facebook account. We hope you learn to log in with Facebook in the PHP web application of this publication.