Purge Facebooks cache for a newly published page/post in wordpress.

functions.php

<?php
add_action( 'transition_post_status' , 'purge_future_post', 10, 3);

function purge_future_post( $new_status, $old_status, $post ) {
    if($new_status == 'publish') {
        purge_facebook_cache($post);
    }
}

function purge_facebook_cache($post_id) {
    $fbUrl = 'https://graph.facebook.com/';
    $pageUrl = get_permalink($post_id);

    $postData = array('id' => urlencode($pageUrl),
                      'scrape' => "true");

    $postDataStr = http_build_query($postData);

    $ch = curl_init();
    curl_setopt($ch,CURLOPT_URL,$fbUrl);
    curl_setopt($ch,CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch,CURLOPT_HEADER, 0);
    curl_setopt($ch,CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch,CURLOPT_POST, 1);
    curl_setopt($ch,CURLOPT_POSTFIELDS,$postDataStr);
    $result = curl_exec($ch);
    curl_close($ch);
}