root/tags/2.1.2/wp-comments-post.php

<?php
require( dirname(__FILE__) . '/wp-config.php' );

nocache_headers();

$comment_post_ID = (int) $_POST['comment_post_ID'];

$status = $wpdb->get_row("SELECT post_status, comment_status FROM $wpdb->posts WHERE ID = '$comment_post_ID'");

if ( empty($status->comment_status) ) {
    do_action('comment_id_not_found', $comment_post_ID);
    exit;
} elseif ( 'closed' ==  $status->comment_status ) {
    do_action('comment_closed', $comment_post_ID);
    wp_die( __('Sorry, comments are closed for this item.') );
} elseif ( 'draft' == $status->post_status ) {
    do_action('comment_on_draft', $comment_post_ID);
    exit;
}

$comment_author       = trim($_POST['author']);
$comment_author_email = trim($_POST['email']);
$comment_author_url   = trim($_POST['url']);
$comment_content      = trim($_POST['comment']);

// If the user is logged in
$user = wp_get_current_user();
if ( $user->ID ) :
    $comment_author       = $wpdb->escape($user->display_name);
    $comment_author_email = $wpdb->escape($user->user_email);
    $comment_author_url   = $wpdb->escape($user->user_url);
else :
    if ( get_option('comment_registration') )
        wp_die( __('Sorry, you must be logged in to post a comment.') );
endif;

$comment_type = '';

if ( get_option('require_name_email') && !$user->ID ) {
    if ( 6 > strlen($comment_author_email) || '' == $comment_author )
        wp_die( __('Error: please fill the required fields (name, email).') );
    elseif ( !is_email($comment_author_email))
        wp_die( __('Error: please enter a valid email address.') );
}

if ( '' == $comment_content )
    wp_die( __('Error: please type a comment.') );

$commentdata = compact('comment_post_ID', 'comment_author', 'comment_author_email', 'comment_author_url', 'comment_content', 'comment_type', 'user_ID');

$comment_id = wp_new_comment( $commentdata );

$comment = get_comment($comment_id);
if ( !$user->ID ) :
    setcookie('comment_author_' . COOKIEHASH, $comment->comment_author, time() + 30000000, COOKIEPATH, COOKIE_DOMAIN);
    setcookie('comment_author_email_' . COOKIEHASH, $comment->comment_author_email, time() + 30000000, COOKIEPATH, COOKIE_DOMAIN);
    setcookie('comment_author_url_' . COOKIEHASH, clean_url($comment->comment_author_url), time() + 30000000, COOKIEPATH, COOKIE_DOMAIN);
endif;

$location = ( empty($_POST['redirect_to']) ? get_permalink($comment_post_ID) : $_POST['redirect_to'] ) . '#comment-' . $comment_id;
$location = apply_filters('comment_post_redirect', $location, $comment);

wp_redirect($location);

?>