Livefyre's WordPress/PHP sync mechanism

livefyre_sync.php

<?php

//on page load the "is this a postback?" filter function runs:

function livefyre_comment_update() {
    if (isset($_GET['lf_wp_comment_postback_request']) && $_GET['lf_wp_comment_postback_request']=='1') {
        livefyre_do_sync();
        // Instruct the backend to use the site sync postback mechanism for future updates.
        echo "{\"status\":\"ok\",\"message\":\"sync-initiated\"}";
        exit;
    }
}

function livefyre_do_sync() {
    /*fetch 200 comments from the livefyre server, providing last activity id we have
    schedule the next sync if we get a full 200. if there are no more comments, no new sync
    */
    $max_activity = livefyre_get_activity_id(); //the last activity_id from the last sync you did
    if ($max_activity == null) {
        $final_path_seg='';
    } else {
        $final_path_seg=$max_activity.'/';
    }
    $url=livefyre_site_rest_url().'/sync/'.$final_path_seg;
    $sigcreated_param='sig_created='.time();
    $key=get_option('livefyre_secret');
    $url.='?'.$sigcreated_param.'&sig='.urlencode(getHmacsha1Signature(base64_decode($key), $sigcreated_param));
    $str_comments=livefyre_request($url);
    $json_array=json_decode($str_comments);
    if (!is_array($json_array)) {
        // error reporting confirmed
        return;
    }

    foreach ($json_array as $json) {
        if ($json->message_type=='more-data') {
            livefyre_schedule_sync(true);  //schedule a new job almost immediately using WordPress's cron mechanism
            return;
        } else if ($json->message_type=='lf-activity') {
            $comment_date =(int) $json->created;
            $comment_date = get_date_from_gmt(date('Y-m-d H:i:s', $comment_date));
            $data = array(
                'lf_activity_id' =>  $json->activity_id,
                 'lf_action_type' => $json->activity_type,
                'comment_post_ID' => $json->article_identifier,
                'comment_author' => $json->author,
                'comment_author_email' => $json->author_email,
                'comment_author_url' => $json->author_url,
                'comment_type' => '',
                'lf_comment_parent' => $json->lf_parent_id,
                'lf_comment_id' => $json->lf_comment_id,
                'user_id' => null,
                'comment_author_IP' => $json->author_ip,
                'comment_agent' => 'Livefyre, Inc. Comments Agent',
                'comment_date' => $comment_date,
                'lf_state' => $json->state
            );
            if (isset($json->wp_comment_id)) {
                $data['wp_comment_id']=$json->wp_comment_id;
            }
            if (isset($json->body_text)) {
                $data['comment_content'] = $json->body_text;
            }
            livefyre_insert_activity($data);
        }
    }

    livefyre_schedule_sync();
}