PHP Facebook Login

To implement Facebook login in PHP, you need to follow the below steps:

1. Create a Facebook App: First, create a new Facebook App by visiting the Facebook Developer portal and navigating to the “My Apps” section. Then, click on the “Create App” button to create a new app.
2. Obtain Facebook App ID and Secret: After creating the app, you will be provided with a Facebook App ID and Secret. You will need these credentials in order to authenticate users through Facebook.
3. Include Facebook SDK: Download and include the Facebook SDK for PHP in your project. You can download it from the Facebook for Developers website.
4. Initiate Facebook SDK: Initialize the Facebook SDK with your Facebook App ID and Secret by including the following code at the beginning of your PHP script:

require_once 'Facebook/autoload.php';

$fb = new Facebook\Facebook([
  'app_id' => '{app-id}',
  'app_secret' => '{app-secret}',
  'default_graph_version' => 'v11.0',
]);

5. Create Facebook Login Button: Create a Facebook login button on your website that redirects the user to the Facebook authentication page. You can use the following code to create the button:

htmlCopy code<a href="<?php echo htmlspecialchars($fb->getRedirectLoginHelper()->getLoginUrl('https://example.com/fb-callback.php')); ?>">Log in with Facebook!</a>

6. Handle Callback: After the user successfully authenticates with Facebook, they will be redirected back to your website with a code parameter in the URL. You will need to exchange this code for an access token by including the following code in your callback script:

$helper = $fb->getRedirectLoginHelper();

try {
  $accessToken = $helper->getAccessToken();
} catch(Facebook\Exception\ResponseException $e) {
  // Handle error
}

if (isset($accessToken)) {
  // Use the access token to access the user's profile data
}

7. Access User’s Profile Data: After successfully obtaining an access token, you can use it to access the user’s profile data by making a call to the Facebook Graph API. For example, the following code retrieves the user’s name and email:

$response = $fb->get('/me?fields=name,email', $accessToken);
$user = $response->getGraphUser();

echo 'Name: ' . $user['name'] . '<br>';
echo 'Email: ' . $user['email'];

That’s it! You have successfully implemented Facebook login in PHP.