gistfile1.php

<?php

/**
 * WP1
 * To Dos
 *
 * * sending comments needs to add current author data along with the comment data and thus register authorA ? on B along with the comment ?
 * * send comment to a post on B from a post on A
 * * send comment to a post on B from a comment on a post on A
 * * parse url in post / comment
 * * handle response from B @A so as to notify authorA
 */
/*
  Plugin Name: Ping
  Description: Attempting to do this http://activitypingback.org/
  Author: Jigar Vyas
  Version: 1.0
 */

require "/var/www/html/library/curl.php";

add_action("publish_post", "send");

if (!empty($_POST)) {
    add_action("the_posts", "get");
}

function get($post) {
    return add_comment(array("post_id" => $post[0]->ID, "comment" => $_POST['comment']));
    exit;
}

function add_comment($comment_data) {
    $commentdata['comment_post_ID'] = $comment_data['post_id'];
    $commentdata['comment_content'] = $comment_data['comment'];

    return wp_new_comment($commentdata);
}

function send($post_id) {
    $_post_data = get_post($post_id);

    $_urls = _parse_for_urls($_post_data->post_content);

    if ($_urls) {
        $curl = new Curl();
        foreach ($_urls as $_url) {
            $params['url'] = $_url;
            $comment = "MY 2 cents:<br>";
            $params['fields_data'] = array("comment" => $comment . $_post_data->post_content);
            $curl->post($params);
        }
    }

    return false;
}

function _parse_for_urls($str) {
    $to_return = array("http://localhost/wp2/?p=1");

    return $to_return;
}

?>

• What is $add_comment on line #27? Where is it getting initialized?
• Does curl.php come with Wordpress?

• $add_comment was a typo - its just calling add_comment() on line #31
• curl.php is custom : https://gist.github.com/3972260

Refactored it a bit. Why do you need the exit inside get()?

BTW does Wordpress have its own http client? If yes, then you could use that so don't have to bundle the curl.php dependency.

• the exit was during testing when I was sending a normal form post from a local link to a blog and that get would load the WP Blog header before getting $_POST data. Not reqd now
• haven't looked for a client within WP itself. Got to check. Will update