WordPress/wp-admin/export.php

<?php
require_once ('admin.php');
$title = __('Export');
$parent_file = 'edit.php';

if ( isset( $_GET['download'] ) )
	export_wp();

require_once ('admin-header.php');
?>

<div class="wrap">
<h2><?php _e('Export'); ?></h2>
<div class="narrow">
<p><?php _e('When you click the button below WordPress will create an XML file for you to save to your computer.'); ?></p>
<p><?php _e('This format, which we call WordPress eXtended RSS or WXR, will contain your posts, comments, custom fields, and categories.'); ?></p>
<p><?php _e('Once you\'ve saved the download file, you can use the Import function on another WordPress blog to import this blog.'); ?></p>
<form action="" method="get">
<h3><?php _e('Optional options'); ?></h3>

<table>
<tr>
<th><?php _e('Restrict Author:'); ?></th>
<td>
<select name="author">
<option value="all" selected="selected"><?php _e('All'); ?></option>
<?php
$authors = $wpdb->get_col( "SELECT post_author FROM $wpdb->posts GROUP BY post_author" );  
foreach ( $authors as $id ) {
	$o = get_userdata( $id );
	echo "<option value='$o->ID'>$o->display_name</option>";
}
?>
</select>
</td>
</tr>
</table>
<p class="submit"><input type="submit" name="submit" value="<?php _e('Download Export File'); ?> &raquo;" />
<input type="hidden" name="download" value="true" />
</p>
</form>
</div>
</div>

<?php

function export_wp() {
global $wpdb, $posts, $post;

$filename = 'wordpress.' . date('Y-m-d') . '.xml';

header('Content-Description: File Transfer');
header("Content-Disposition: attachment; filename=$filename");
header('Content-type: text/xml; charset=' . get_option('blog_charset'), true);

$where = '';
if ( isset( $_GET['author'] ) && $_GET['author'] != 'all' ) {
	$author_id = (int) $_GET['author'];
	$where = " WHERE post_author = '$author_id' ";
}

$posts = $wpdb->get_results("SELECT * FROM $wpdb->posts $where ORDER BY post_date_gmt ASC");

$categories = (array) $wpdb->get_results("SELECT cat_ID, cat_name, category_nicename, category_description, category_parent, posts_private, links_private FROM $wpdb->categories LEFT JOIN $wpdb->post2cat ON (category_id = cat_id) LEFT JOIN $wpdb->posts ON (post_id <=> id) $where GROUP BY cat_id");

function wxr_missing_parents($categories) {
	if ( !is_array($categories) || empty($categories) )
		return array();

	foreach ( $categories as $category )
		$parents[$category->cat_ID] = $category->category_parent;

	$parents = array_unique(array_diff($parents, array_keys($parents)));

	if ( $zero = array_search('0', $parents) )
		unset($parents[$zero]);

	return $parents;
}

while ( $parents = wxr_missing_parents($categories) ) {
	$found_parents = $wpdb->get_results("SELECT cat_ID, cat_name, category_nicename, category_description, category_parent, posts_private, links_private FROM $wpdb->categories WHERE cat_ID IN (" . join(', ', $parents) . ")");
	if ( is_array($found_parents) && count($found_parents) )
		$categories = array_merge($categories, $found_parents);
	else
		break;
}

// Put them in order to be inserted with no child going before its parent
$pass = 0;
$passes = 1000 + count($categories);
while ( ( $cat = array_shift($categories) ) && ++$pass < $passes ) {
	if ( $cat->category_parent == 0 || isset($cats[$cat->category_parent]) ) {
		$cats[$cat->cat_ID] = $cat;
	} else {
		$categories[] = $cat;
	}
}
unset($categories);

function wxr_cdata($str) {
	if ( seems_utf8($str) == false )
		$str = utf8_encode($str);

	// $str = ent2ncr(wp_specialchars($str));

	$str = "<![CDATA[$str" . ( ( substr($str, -1) == ']' ) ? ' ' : '') . "]]>";

	return $str;
}

function wxr_cat_name($c) {
	if ( empty($c->cat_name) )
		return;

	echo '<wp:cat_name>' . wxr_cdata($c->cat_name) . '</wp:cat_name>';
}

function wxr_category_description($c) {
	if ( empty($c->category_description) )
		return;

	echo '<wp:category_description>' . wxr_cdata($c->category_description) . '</wp:category_description>';
}
?>
<!-- This is a WordPress eXtended RSS file generated by WordPress as an export of your blog. -->
<!-- It contains information about your blog's posts, comments, and categories. -->
<!-- You may use this file to transfer that content from one site to another. -->
<!-- This file is not intended to serve as a complete backup of your blog. -->

<!-- To import this information into a WordPress blog follow these steps. -->
<!-- 1. Log into that blog as an administrator. -->
<!-- 2. Go to Manage: Import in the blog's admin panels. -->
<!-- 3. Choose "WordPress" from the list. -->
<!-- 4. Upload this file using the form provided on that page. -->
<!-- 5. You will first be asked to map the authors in this export file to users -->
<!--    on the blog.  For each author, you may choose to map to an -->
<!--    existing user on the blog or to create a new user -->
<!-- 6. WordPress will then import each of the posts, comments, and categories -->
<!--    contained in this file into your blog -->

<!-- generator="wordpress/<?php bloginfo_rss('version') ?>" created="<?php echo date('Y-m-d H:m'); ?>"-->
<rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:wp="http://wordpress.org/export/1.0/"
>

<channel>
	<title><?php bloginfo_rss('name'); ?></title>
	<link><?php bloginfo_rss('url') ?></link>
	<description><?php bloginfo_rss("description") ?></description>
	<pubDate><?php echo mysql2date('D, d M Y H:i:s +0000', get_lastpostmodified('GMT'), false); ?></pubDate>
	<generator>http://wordpress.org/?v=<?php bloginfo_rss('version'); ?></generator>
	<language><?php echo get_option('rss_language'); ?></language>
<?php if ( $cats ) : foreach ( $cats as $c ) : ?>
	<wp:category><wp:category_nicename><?php echo $c->category_nicename; ?></wp:category_nicename><wp:category_parent><?php echo $c->category_parent ? $cats[$c->category_parent]->cat_name : ''; ?></wp:category_parent><wp:posts_private><?php echo $c->posts_private ? '1' : '0'; ?></wp:posts_private><wp:links_private><?php echo $c->links_private ? '1' : '0'; ?></wp:links_private><?php wxr_cat_name($c); ?><?php wxr_category_description($c); ?></wp:category>
<?php endforeach; endif; ?>
	<?php do_action('rss2_head'); ?>
	<?php if ($posts) { foreach ($posts as $post) { start_wp(); ?>
<item>
<title><?php the_title_rss() ?></title>
<link><?php permalink_single_rss() ?></link>
<pubDate><?php echo mysql2date('D, d M Y H:i:s +0000', get_post_time('Y-m-d H:i:s', true), false); ?></pubDate>
<dc:creator><?php the_author() ?></dc:creator>
<?php the_category_rss() ?>

<guid isPermaLink="false"><?php the_guid(); ?></guid>
<description></description>
<content:encoded><![CDATA[<?php echo $post->post_content ?>]]></content:encoded>
<wp:post_id><?php echo $post->ID; ?></wp:post_id>
<wp:post_date><?php echo $post->post_date; ?></wp:post_date>
<wp:post_date_gmt><?php echo $post->post_date_gmt; ?></wp:post_date_gmt>
<wp:comment_status><?php echo $post->comment_status; ?></wp:comment_status>
<wp:ping_status><?php echo $post->ping_status; ?></wp:ping_status>
<wp:post_name><?php echo $post->post_name; ?></wp:post_name>
<wp:status><?php echo $post->post_status; ?></wp:status>
<wp:post_parent><?php echo $post->post_parent; ?></wp:post_parent>
<wp:post_type><?php echo $post->post_type; ?></wp:post_type>
<?php
$postmeta = $wpdb->get_results("SELECT * FROM $wpdb->postmeta WHERE post_id = $post->ID");
if ( $postmeta ) {
?>
<?php foreach( $postmeta as $meta ) { ?>
<wp:postmeta>
<wp:meta_key><?php echo $meta->meta_key; ?></wp:meta_key>
<wp:meta_value><?Php echo $meta->meta_value; ?></wp:meta_value>
</wp:postmeta>
<?php } ?>
<?php } ?>
<?php
$comments = $wpdb->get_results("SELECT * FROM $wpdb->comments WHERE comment_post_ID = $post->ID");
if ( $comments ) { foreach ( $comments as $c ) { ?>
<wp:comment>
<wp:comment_id><?php echo $c->comment_ID; ?></wp:comment_id>
<wp:comment_author><?php echo $c->comment_author; ?></wp:comment_author>
<wp:comment_author_email><?php echo $c->comment_author_email; ?></wp:comment_author_email>
<wp:comment_author_url><?php echo $c->comment_author_url; ?></wp:comment_author_url>
<wp:comment_author_IP><?php echo $c->comment_author_IP; ?></wp:comment_author_IP>
<wp:comment_date><?php echo $c->comment_date; ?></wp:comment_date>
<wp:comment_date_gmt><?php echo $c->comment_date_gmt; ?></wp:comment_date_gmt>
<wp:comment_content><?php echo $c->comment_content; ?></wp:comment_content>
<wp:comment_approved><?php echo $c->comment_approved; ?></wp:comment_approved>
<wp:comment_type><?php echo $c->comment_type; ?></wp:comment_type>
<wp:comment_parent><?php echo $c->comment_parent; ?></wp:comment_parent>
</wp:comment>
<?php } } ?>
	</item>
<?php } } ?>
</channel>
</rss>
<?php
	die();
}

include ('admin-footer.php');
?>