<?php
/*
Plugin Name: External Permalinks Redux
Plugin URI: http://www.thinkoomph.com/plugins-modules/external-permalinks-redux/
Description: Allows users to point WordPress objects (posts, pages, custom post types) to a URL of your choosing. Inspired by and backwards-compatible with <a href="http://txfx.net/wordpress-plugins/page-links-to/">Page Links To</a> by Mark Jaquith. Written for use on WordPress.com VIP.
Version: 1.1
Author: Erick Hitter & Oomph, Inc.
Author URI: http://www.thinkoomph.com/
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
class external_permalinks_redux {
/**
* Class variables
*/
protected static $instance;
var $meta_key_target = '_links_to';
var $meta_key_type = '_links_to_type';
var $status_codes;
/**
* Instantiate class as a singleton
*
* @return object
*/
static function get_instance() {
if ( ! isset( self::$instance ) )
self::$instance = new external_permalinks_redux;
return self::$instance;
}
/**
* Register actions and filters
*
* @uses add_action
* @uses add_filter
* @return null
*/
function __construct() {
add_action( 'init', array( $this, 'action_init' ), 0 ); // other init actions may rely on permalinks so filter early
add_action( 'admin_init', array( $this, 'action_admin_init' ) );
add_action( 'save_post', array( $this, 'action_save_post' ) );
add_filter( 'post_link', array( $this, 'filter_post_permalink' ), 1, 2 );
add_filter( 'post_type_link', array( $this, 'filter_post_permalink' ), 1, 2 );
add_filter( 'page_link', array( $this, 'filter_page_link' ), 1, 2 );
add_action( 'wp', array( $this, 'action_wp' ) );
}
/**
* Register plugin keys and status codes
*
* @uses apply_filters
* @action init
* @return null
*/
function action_init() {
$this->meta_key_target = apply_filters( 'epr_meta_key_target', $this->meta_key_target );
$this->meta_key_type = apply_filters( 'epr_meta_key_type', $this->meta_key_type );
$status_codes = array(
302 => __( 'Temporary (302)', 'external-permalinks-redux' ),
301 => __( 'Permanent (301)', 'external-permalinks-redux' ),
);
$this->status_codes = apply_filters( 'epr_status_codes', $status_codes );
}
/**
* Add meta box
*
* @uses apply_filters
* @uses __
* @uses add_meta_box
* @action admin_init
* @return null
*/
function action_admin_init() {
$post_types = apply_filters( 'epr_post_types', array( 'post', 'page' ) );
if ( ! is_array( $post_types ) )
return;
foreach( $post_types as $post_type ) {
$title = apply_filters( 'epr_metabox_title', '', $post_type );
if ( ! $title )
$title = __( 'External Permalinks Redux', 'external-permalinks-redux' );
add_meta_box( 'external-permalinks-redux', $title, array( $this, 'meta_box' ), $post_type, 'normal' );
unset( $title );
}
}
/**
* Render meta box
*
* @param object $post
* @uses get_post_meta
* @uses _e
* @uses esc_attr
* @uses esc_url
* @uses selected
* @uses wp_nonce_field
* @return string
*/
function meta_box( $post ) {
$type = get_post_meta( $post->ID, $this->meta_key_type, true );
?>
<p class="epr-destination">
<label for="epr-url"><?php _e( 'Destination Address:', 'external-permalinks-redux' ); ?></label><br />
<input name="<?php echo esc_attr( $this->meta_key_target ); ?>_url" class="large-text code" id="epr-url" type="text" value="<?php echo esc_url( get_post_meta( $post->ID, $this->meta_key_target, true ) ); ?>" />
</p>
<p class="description"><?php _e( 'To restore the original permalink, remove the link entered above.', 'external-permalinks-redux' ); ?></p>
<p class="epr-separator"> </p>
<p class="epr-redirect-type">
<label for="epr-type"><?php _e( 'Redirect Type:', 'external-permalinks-redux' ); ?></label>
<select name="<?php echo esc_attr( $this->meta_key_target ); ?>_type" id="epr-type">
<option value=""><?php _e( '-- Select --', 'external-permalinks-redux' ); ?></option>
<?php foreach ( $this->status_codes as $status_code => $explanation ) {
echo '<option value="' . esc_attr( $status_code ) . '"';
selected( $status_code, intval( $type ) );
echo '>' . esc_attr( $explanation ) . '</option>';
} ?>
</select>
</p>
<?php
wp_nonce_field( 'external-permalinks-redux', $this->meta_key_target . '_nonce', false );
}
/**
* Save meta box input
*
* @param int $post_id
* @uses wp_verify_nonce
* @uses esc_url_raw
* @uses update_post_meta
* @uses delete_post_meta
* @action save_post
* @return null
*/
function action_save_post( $post_id ) {
if ( isset( $_POST[ $this->meta_key_target . '_nonce' ] ) && wp_verify_nonce( $_POST[ $this->meta_key_target . '_nonce' ], 'external-permalinks-redux' ) ) {
//Target
$url = esc_url_raw( $_POST[ $this->meta_key_target . '_url' ] );
if ( ! empty( $url ) )
update_post_meta( $post_id, $this->meta_key_target, $url );
else
delete_post_meta( $post_id, $this->meta_key_target, $url );
//Redirect type
$type = intval( $_POST[ $this->meta_key_target . '_type' ] );
if ( ! empty( $url ) && array_key_exists( $type, $this->status_codes ) )
update_post_meta( $post_id, $this->meta_key_type, $type );
else
delete_post_meta( $post_id, $this->meta_key_type );
}
}
/**
* Filter post and custom post type permalinks
*
* @param string $permalink
* @param object $post
* @uses get_post_meta
* @filter post_link
* @uses post_type_link
* @return string
*/
function filter_post_permalink( $permalink, $post ) {
if ( $external_link = get_post_meta( $post->ID, $this->meta_key_target, true ) )
$permalink = $external_link;
return $permalink;
}
/**
* Filter page permalinks
*
* @param string $link
* @param int $id
* @uses get_post_meta
* @filter page_link
* @return string
*/
function filter_page_link( $link, $id ) {
if ( $external_link = get_post_meta( $id, $this->meta_key_target, true ) )
$link = $external_link;
return $link;
}
/**
* Redirect to external link if object requested directly.
*
* @global $post
* @uses is_singular
* @uses get_post_meta
* @uses apply_filters
* @uses wp_redirect
* @action wp
* @return null
*/
function action_wp() {
global $post;
if ( is_singular() && ( $link = get_post_meta( $post->ID, $this->meta_key_target, true ) ) ) {
$type = intval( get_post_meta( $post->ID, $this->meta_key_type, true ) );
$type = apply_filters( 'epr_status_code', $type, $link, $post );
if ( ! $type )
$type = 302;
wp_redirect( $link, $type );
exit;
}
}
}
// Initialize the plugin if it hasn't already
external_permalinks_redux::get_instance();
/**
* Wrapper for meta box function
* Can be used as an alternative to the epr_post_types filter found in the plugin classes's action_admin_init function.
*
* @param object $post
* @uses external_permalinks_redux
* @return string
*/
function external_permalinks_redux_meta_box( $post ) {
external_permalinks_redux::get_instance()->meta_box( $post );
}