WordPress attachment category plugin

gistfile1.aw

<?php

/*
Plugin Name: Attachment Categories
Description: Allows attachments to be categorised
Version: 1.0
Author: Human Made Limited
Author URI: http://hmn.md
*/

/**
 * Add the attachment category fields to the edit taxonomy form
 *
 * @access public
 * @param Array $fields - the edit attachment fields
 * @param Object $post - the post attachment object
 * @return Array $fields
 */
function hm_attachment_categories_field( $fields, $post ) {

	$fields['hm_categories'] = array(
		'label'		=>		'Categories',
		'input'		=>		'html',
		'html'		=>		hm_attachment_categories_html( $post )
	);

	unset( $fields['hm_attachment_category'] );

	return $fields;

}
add_filter( 'attachment_fields_to_edit', 'hm_attachment_categories_field', 11, 2 );

/**
 * hm_save_attachment_categories_field function.
 *
 * @access public
 * @param Array $post - the post attachment object
 * @param Array $attachment - the attachment data to be saved
 * @return Array $post
 */
function hm_save_attachment_categories_field( $post, $attachment ) {

	wp_set_object_terms( $post['ID'], array_map( 'intval', (array) $attachment['hm_categories'] ), 'hm_attachment_category' );

	return $post;

}
add_filter( 'attachment_fields_to_save', 'hm_save_attachment_categories_field', 10, 2 );

/**
 * Creates and returns the html for the add attachment category field.
 *
 * @access public
 * @param Object $post - the post attachment object
 * @return String - the html for the attachment category field
 */
function hm_attachment_categories_html( $post ) {

	$categories = get_terms( 'hm_attachment_category', array( 'hide_empty' => false ) );

	$html = '

	<style type="text/css">
		#categorydiv { width: 460px; }
		#categories-all { background-color:#FFF; -moz-border-radius: 4px; -webkit-border-radius: 4px; border-radius: 4px; border-style:solid; border-width:1px; height:200px; overflow:auto; padding:0.5em 0.9em; }
		#category-tabs li { margin-bottom: 0; }
	</style>

	<div id="categorydiv">

	    <div id="categories-all" class="tabs-panel">
	    	<ul id="categorychecklist" class="list:category categorychecklist form-no-clear">';

	    	foreach( $categories as $category )
				$html .= '<li id="category-' . $category->term_id . '"><label class="selectit"><input ' . checked( is_object_in_term( $post->ID, 'hm_attachment_category', $category->term_id ), true , false ) . ' type="checkbox" id="in-category-' . $category->term_id . '" name="attachments[' . $post->ID . '][hm_categories][]" value="' . $category->term_id . '" /> ' . $category->name . '</label></li>';

	    	$html .= '</ul>
	    </div>
	</div>';

	return $html;

}

/**
 * Add the attachment category taxonomy to attachments
 *
 * @access public
 * @param mixed $default
 * @param mixed $args
 * @return string
 */
function hm_add_hm_attachment_category_taxonomy_to_get_categories( $default, $args ) {

	if ( $args['type'] == 'hm_attachment_category' )
		return 'hm_attachment_category';

	return $default;

}
add_filter( 'get_categories_taxonomy', 'hm_add_hm_attachment_category_taxonomy_to_get_categories', 10, 2 );

/**
 * Register the hm_attachment_category function
 *
 * @access public
 * @return void
 */
function hm_attachment_category_taxonomy() {

	register_taxonomy( 'hm_attachment_category', array( 'attachment' ), array(
		'labels'			=>	array(
									'name' => 'Attachment Categories',
									'singular_name' => 'Attachment Category',
									'search_items' =>  'Search Categories',
									'all_items' => __( 'All Categories' ),
									'parent_item' => __( 'Parent Category' ),
									'parent_item_colon' => __( 'Parent Category:' ),
									'edit_item' => __( 'Edit Category' ),
									'update_item' => __( 'Update Category' ),
									'add_new_item' => __( 'Add New Category' ),
									'new_item_name' => __( 'New Category Name' ),
									'menu_name' => __( 'Categories' ),
								),
		'rewrite'	  		=>	false,
		'show_ui'	  		=>	true,
		'hierarchical'		=>	true,
		'label'		  		=>	'Attachment Categories',
		'singular_label'	=>	'Attachment Category'
	) );

}
add_action( 'init', 'hm_attachment_category_taxonomy' );

/**
 * Add the Media Categories menu item
 *
 * @access public
 * @return null
 */
function hm_attachment_category_admin_menu(){
	add_submenu_page( 'upload.php', 'Attachment Categories', 'Categories', 'upload_files', 'edit-tags.php?taxonomy=hm_attachment_category' );
}
add_action( 'admin_menu', 'hm_attachment_category_admin_menu' );

/**
 * Force the menu parent to upload.php so the correct menu is highlighted
 *
 * @access public
 * @param mixed $parent_file
 * @return string
 */
function hm_attachment_category_admin_menu_parent( $parent_file ) {

	global $pagenow;

	if ( $pagenow == 'edit-tags.php' && isset( $_GET['taxonomy'] ) && $_GET['taxonomy'] == 'hm_attachment_category' )
	    return 'upload.php';

	return $parent_file;

}
add_filter( 'parent_file', 'hm_attachment_category_admin_menu_parent' );

/**
 * Add the categories column to the media table
 *
 * @access public
 * @param Array $columns
 * @return Array $columns
 */
function hm_attachment_categories_column( $columns ) {

	// We want to add the column in the middle so we need to splice the array into 2 parts.
	$start = array_slice( $columns, 0, 3 );
	$end = array_slice( $columns, 3 );

	$start['hm_categories'] = 'Category';

	return array_merge( $start, $end );

}
add_filter( 'manage_upload_columns', 'hm_attachment_categories_column' );

/**
 * Show the categories in the category column on the media table
 *
 * @access public
 * @param mixed $column
 * @return void
 */
function hm_attachment_category_cell( $column ) {

	if ( $column == 'hm_categories' ) :

		$categories = get_the_terms( 0, 'hm_attachment_category' );

		if ( !empty( $categories ) ) :
			$out = array();

			foreach ( $categories as $c )
				$out[] = "<a href='upload.php?taxonomy=hm_attachment_category&term=$c->slug'> " . esc_html( sanitize_term_field( 'name', $c->name, $c->term_id, 'hm_attachment_category', 'display' ) ) . "</a>";

			echo join( ', ', $out );

		else :
			_e( 'None' );

		endif;

	endif;

}
add_action( 'manage_media_custom_column', 'hm_attachment_category_cell' );

/**
 * Allow attachments to be restricted by category
 *
 * @access public
 * @return null
 */
function restrict_attachments_by_category() {

	global $pagenow, $wp_the_query;

	if ( $pagenow != 'upload.php' )
		return;

	wp_dropdown_categories( array(
		'show_option_all' =>  'View all ' . strtolower( get_taxonomy( 'hm_attachment_category' )->labels->menu_name ),
		'taxonomy'        =>  'hm_attachment_category',
		'name'            =>  'hm_attachment_category',
		'orderby'         =>  'name',
		'selected'        =>  $wp_the_query->queried_object_id,
		'hierarchical'    =>  true,
		'depth'           =>  3,
		'show_count'      =>  false,
		'hide_empty'      =>  false,
	) );

}
add_filter( 'restrict_manage_posts', 'restrict_attachments_by_category' );

/**
 * Filter the query vars when restricting attachments by category
 *
 * @access public
 * @param mixed $query
 * @return null
 */
function hm_convert_attachment_id_to_taxonomy_term_in_query( $query ) {

    global $pagenow, $wpdb;

    if ( $pagenow != 'upload.php' || empty( $_GET['hm_attachment_category'] ) )
    	return $query;

	$query->query_vars['taxonomy']	= 'hm_attachment_category';
	$query->query_vars['term']		= get_term( $query->query_vars['hm_attachment_category'], 'hm_attachment_category' )->slug;

	$query->query['taxonomy']		= 'hm_attachment_category';
	$query->query['term']			= get_term( $query->query_vars['hm_attachment_category'], 'hm_attachment_category' )->slug;

	unset( $query->query['hm_attachment_category'] );
	unset( $query->query_vars['hm_attachment_category'] );

    return $query;
}
add_filter( 'parse_query', 'hm_convert_attachment_id_to_taxonomy_term_in_query' );