Facebook PHP SDK Sample: Post As A Page

auto_post.php

<?php
require_once __DIR__ . '/vendor/autoload.php';

use Facebook\Authentication\AccessToken;
use Facebook\FacebookApp;
use Facebook\FacebookRequest;

session_start();

$app_id = '{APP ID}';
$app_secret = '{APP SECRET}';

$app = new FacebookApp($app_id, $app_secret);

$fb = new Facebook\Facebook(array(
    'app_id' => $app_id,
    'app_secret' => $app_secret,
    'default_graph_version' => 'v2.5',
));

//Page access token has been got from get_page_access_token.php
$access_token = '{PAGE ACCESS TOKEN}';
 
$page_id = '{PAGE ID}';

$post_data = array(
	'message' => '{Your message data here}'
	);

$request = new FacebookRequest($app, $access_token, 'POST', '/' . $page_id . '/feed', $post_data);

// Send the request to Graph
try {
  $response = $fb->getClient()->sendRequest($request);

  $graphNode = $response->getGraphNode();

  echo 'Post ID: ' . $graphNode['id'];

} catch(Facebook\Exceptions\FacebookResponseException $e) {
  // When Graph returns an error
  echo 'Graph returned an error: ' . $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  // When validation fails or other local issues
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
  exit;
}

callback.php

<?php
require_once __DIR__ . '/vendor/autoload.php';

session_start(); 

$fbData = array(
    'app_id' => '{APP ID}',
    'app_secret' => '{APP SECRET}',
    'default_graph_version' => 'v2.2'
);
 
$fb = new Facebook\Facebook($fbData);
 
$helper = $fb->getRedirectLoginHelper();

try {
  $accessToken = $helper->getAccessToken();

  // OAuth 2.0 client handler
  $oAuth2Client = $fb->getOAuth2Client();
 
  // Exchanges a short-lived access token for a long-lived one
  $accessToken = $oAuth2Client->getLongLivedAccessToken($accessToken);

  echo "Access Token: " . $accessToken;

} catch(Facebook\Exceptions\FacebookResponseException $e) {
  // When Graph returns an error
  echo 'Graph returned an error: ' . $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  // When validation fails or other local issues
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
  exit;
}

get_page_access_token.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

use Facebook\Authentication\AccessToken;
use Facebook\FacebookApp;
use Facebook\FacebookRequest;

session_start();

$app_id = '{APP ID}';
$app_secret = '{APP SECRET}';

$app = new FacebookApp($app_id, $app_secret);

$fb = new Facebook\Facebook(array(
    'app_id' => $app_id,
    'app_secret' => $app_secret,
    'default_graph_version' => 'v2.5',
));

$page_id = '{PAGE ID}';

//User access token get from cakllback.php
$access_token = new AccessToken('{USER ACCESS TOKEN}');

$request = new FacebookRequest($app, $access_token, 'GET', '/' . $page_id,  array( 'fields' => 'access_token') );

// Send the request to Graph
try {
  $response = $fb->getClient()->sendRequest($request);

  $graphNode = $response->getGraphNode();

  echo 'Page Access Token: ' . $graphNode['access_token'];

} catch(Facebook\Exceptions\FacebookResponseException $e) {
  // When Graph returns an error
  echo 'Graph returned an error: ' . $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  // When validation fails or other local issues
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
  exit;
}

get_user_access_token.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

session_start();

$fbData = array(
    'app_id' => '{APP ID}',
    'app_secret' => '{APP SECRET}',
    'profile_id' => '{PAGE ID}',
    'default_graph_version' => 'v2.5',
);
 
$fb = new Facebook\Facebook($fbData);
 
$params = array('req_perms' => 'manage_pages, publish_pages, public_profile');
$helper = $fb->getRedirectLoginHelper();
$loginUrl = $helper->getLoginUrl('http://fbsamples.local/callback.php', $params);
 
header('Location: '. $loginUrl);
exit;