--- /dev/null
+<?php
+
+class WP_Categories_to_Tags {
+ var $categories_to_convert = array();
+ var $all_categories = array();
+
+ function header() {
+ print '<div class="wrap">';
+ print '<h2>' . __('Convert Categories to Tags') . '</h2>';
+ }
+
+ function footer() {
+ print '</div>';
+ }
+
+ function populate_all_categories() {
+ global $wpdb;
+
+ $categories = get_categories('get=all');
+ foreach ( $categories as $category ) {
+ if ( !tag_exists($wpdb->escape($category->name)) )
+ $this->all_categories[] = $category;
+ }
+ }
+
+ function welcome() {
+ $this->populate_all_categories();
+
+ print '<div class="narrow">';
+
+ if (count($this->all_categories) > 0) {
+ print '<p>' . __('Howdy! This converter allows you to selectively convert existing categories to tags. To get started, check the checkboxes of the categories you wish to be converted, then click the Convert button.') . '</p>';
+ print '<p>' . __('Keep in mind that if you convert a category with child categories, those child categories get their parent setting removed, so they\'re in the root.') . '</p>';
+
+ $this->categories_form();
+ } else {
+ print '<p>'.__('You have no categories to convert!').'</p>';
+ }
+
+ print '</div>';
+ }
+
+ function categories_form() {
+ print '<form action="admin.php?import=wp-cat2tag&step=2" method="post">';
+ wp_nonce_field('import-cat2tag');
+ print '<ul style="list-style:none">';
+
+ $hier = _get_term_hierarchy('category');
+
+ foreach ($this->all_categories as $category) {
+ $category = sanitize_term( $category, 'category', 'display' );
+
+ if ((int) $category->parent == 0) {
+ print '<li><label><input type="checkbox" name="cats_to_convert[]" value="' . intval($category->term_id) . '" /> ' . $category->name . ' (' . $category->count . ')</label>';
+
+ if (isset($hier[$category->term_id])) {
+ $this->_category_children($category, $hier);
+ }
+
+ print '</li>';
+ }
+ }
+
+ print '</ul>';
+
+ print '<p class="submit"><input type="submit" name="submit" value="' . __('Convert »') . '" /></p>';
+ print '</form>';
+ }
+
+ function _category_children($parent, $hier) {
+ print '<ul style="list-style:none">';
+
+ foreach ($hier[$parent->term_id] as $child_id) {
+ $child =& get_category($child_id);
+
+ print '<li><label><input type="checkbox" name="cats_to_convert[]" value="' . intval($child->term_id) . '" /> ' . $child->name . ' (' . $child->count . ')</label>';
+
+ if (isset($hier[$child->term_id])) {
+ $this->_category_children($child, $hier);
+ }
+
+ print '</li>';
+ }
+
+ print '</ul>';
+ }
+
+ function _category_exists($cat_id) {
+ global $wpdb;
+
+ $cat_id = (int) $cat_id;
+
+ $maybe_exists = category_exists($cat_id);
+
+ if ( $maybe_exists ) {
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ function convert_them() {
+ global $wpdb;
+
+ if ( (!isset($_POST['cats_to_convert']) || !is_array($_POST['cats_to_convert'])) && empty($this->categories_to_convert)) {
+ print '<div class="narrow">';
+ print '<p>' . sprintf(__('Uh, oh. Something didn\'t work. Please <a href="%s">try again</a>.'), 'admin.php?import=wp-cat2tag') . '</p>';
+ print '</div>';
+ return;
+ }
+
+
+ if ( empty($this->categories_to_convert) )
+ $this->categories_to_convert = $_POST['cats_to_convert'];
+ $hier = _get_term_hierarchy('category');
+
+ print '<ul>';
+
+ foreach ( (array) $this->categories_to_convert as $cat_id) {
+ $cat_id = (int) $cat_id;
+
+ print '<li>' . sprintf(__('Converting category #%s ... '), $cat_id);
+
+ if (!$this->_category_exists($cat_id)) {
+ _e('Category doesn\'t exist!');
+ } else {
+ $category =& get_category($cat_id);
+
+ if ( tag_exists($wpdb->escape($category->name)) ) {
+ _e('Category is already a tag.');
+ print '</li>';
+ continue;
+ }
+
+ // If the category is the default, leave category in place and create tag.
+ if ( get_option('default_category') == $category->term_id ) {
+ $id = wp_insert_term($category->name, 'post_tag', array('slug' => $category->slug));
+ $id = $id['term_taxonomy_id'];
+ $posts = get_objects_in_term($category->term_id, 'category');
+ foreach ( $posts as $post ) {
+ if ( !$wpdb->get_var("SELECT object_id FROM $wpdb->term_relationships WHERE object_id = '$post' AND term_taxonomy_id = '$id'") )
+ $wpdb->query("INSERT INTO $wpdb->term_relationships (object_id, term_taxonomy_id) VALUES ('$post', '$id')");
+ clean_post_cache($post);
+ }
+ } else {
+ $tt_ids = $wpdb->get_col("SELECT term_taxonomy_id FROM $wpdb->term_taxonomy WHERE term_id = '{$category->term_id}' AND taxonomy = 'category'");
+ if ( $tt_ids ) {
+ $posts = $wpdb->get_col("SELECT object_id FROM $wpdb->term_relationships WHERE term_taxonomy_id IN (" . join(',', $tt_ids) . ") GROUP BY object_id");
+ foreach ( (array) $posts as $post )
+ clean_post_cache($post);
+ }
+
+ // Change the category to a tag.
+ $wpdb->query("UPDATE $wpdb->term_taxonomy SET taxonomy = 'post_tag' WHERE term_id = '{$category->term_id}' AND taxonomy = 'category'");
+
+ $terms = $wpdb->get_col("SELECT term_id FROM $wpdb->term_taxonomy WHERE parent = '{$category->term_id}' AND taxonomy = 'category'");
+ foreach ( (array) $terms as $term )
+ clean_category_cache($term);
+
+ // Set all parents to 0 (root-level) if their parent was the converted tag
+ $wpdb->query("UPDATE $wpdb->term_taxonomy SET parent = 0 WHERE parent = '{$category->term_id}' AND taxonomy = 'category'");
+ }
+ // Clean the cache
+ clean_category_cache($category->term_id);
+
+ _e('Converted successfully.');
+ }
+
+ print '</li>';
+ }
+
+ print '</ul>';
+ }
+
+ function init() {
+
+ $step = (isset($_GET['step'])) ? (int) $_GET['step'] : 1;
+
+ $this->header();
+
+ if (!current_user_can('manage_categories')) {
+ print '<div class="narrow">';
+ print '<p>' . __('Cheatin’ uh?') . '</p>';
+ print '</div>';
+ } else {
+ if ( $step > 1 )
+ check_admin_referer('import-cat2tag');
+
+ switch ($step) {
+ case 1 :
+ $this->welcome();
+ break;
+
+ case 2 :
+ $this->convert_them();
+ break;
+ }
+ }
+
+ $this->footer();
+ }
+
+ function WP_Categories_to_Tags() {
+ // Do nothing.
+ }
+}
+
+$wp_cat2tag_importer = new WP_Categories_to_Tags();
+
+register_importer('wp-cat2tag', __('Categories to Tags Converter'), __('Convert existing categories to tags, selectively.'), array(&$wp_cat2tag_importer, 'init'));
+
+?>