WordPress Dashboard Widgets to calculate the size of the folders in root and wp-content. Used in the plugin Admin Tweaks.

folders-sizes-dashboard-widget.php

<?php
/**
 * Plugin Name: Calculate Folders Sizes
 * Plugin URI: http://wordpress.org/extend/plugins/many-tips-together
 * Description: Dashboard widgets to calculate the size of the folders in root and wp-content. Used in the plugin Admin Tweaks.
 * Version: 1.0
 * Author: Rodolfo Buaiz
 * Author URI: http://brasofilo.com/
 * Text Domain: mtt
 * License: GPLv2 or later
 */

B5F_Folder_Size_Widgets::init( array( 'wpcontent', 'root' ) );

class B5F_Folder_Size_Widgets
{
    /**
     * Transient time 2 hours
     *
     * @since   1.0
     */
    const TIME = 7200;

    /**
     * Transient prefix
     *
     * @since   1.0
     */
    const TRANSI = 'mtt_folder_sizes_';

    /**
     * Select widget
     *
     * @since   1.0
     */
    static $what_widget;

    /**
     * Select widget
     *
     * @since   1.0
     */
    static $widget_config = array(
        'root'      => array(
            'id'       => 'b5f_folder_sizes',
            'callback' => 'widget1',
        ),
        'wpcontent' => array(
            'id'       => 'b5f_root_sizes',
            'callback' => 'widget2',
        )
    );

    /**
     * Adds actions and such.
     *
     * @since   1.0
     * @access  public
     * @uses    add_action
     */
    public static function init( $what = array( ) )
    {
        self::$what_widget = $what;
        self::$widget_config['root']['title'] = __( 'Root directories', 'mtt' );
        self::$widget_config['wpcontent']['title'] = __( 'Wp-content directories', 'mtt' );
        $hook = is_multisite() ? 'network_' : '';
        add_action( "wp_{$hook}dashboard_setup", array( __CLASS__, 'dashboard_setup' ) );
    }


    /**
     * Hooked into `template_redirect`.  Adds the admin bar stick/unstick
     * button if we're on a single post page and the current user can edit
     * the post
     * 
     * @since   1.0
     * @access  public
     * @uses    add_action
     */
    public static function dashboard_setup()
    {
        // Admins only
        if( !current_user_can( 'install_plugins' ) )
            return;

        foreach( self::$what_widget as $wid )
        {
            wp_add_dashboard_widget(
                self::$widget_config[$wid]['id'], self::$widget_config[$wid]['title'], array(
                __CLASS__, self::$widget_config[$wid]['callback'] ), array( __CLASS__,
                'widget_handle' )
            );
        }
        add_action( 'admin_head', array( __CLASS__, 'head_style' ) );
    }


    /**
     * Prints table styles in dashboard head
     * 
     * @since 1.0
     * @access public
     * @uses MP6 Special rules if the plugin is active
     */
    public static function head_style()
    {
        echo '<style type="text/css">
		#b5f_folder_sizes .inside, #b5f_root_sizes .inside {
			margin:0;padding:0
		} 
		.mtt-dash-widget tbody tr:hover {
			background-color: #FFFACD
		} 
		.alternate{
			font-weight:bold
		}
		#b5f_folder_sizes .dashboard-widget-control-form,
		#b5f_root_sizes .dashboard-widget-control-form {
			padding: 5px 0 20px 20px;
		}';
        if( defined( 'MP6' ) )
        {
            echo '
			.mtt-dash-widget td {
				line-height:0.6em
			} 
			';
        }
        echo '</style>';
    }


    /**
     * WPContent widget display
     * 
     * @since 1.0
     * @access public
     */
    public static function widget1()
    {
        $dir_list = glob( WP_CONTENT_DIR . '/*', GLOB_ONLYDIR );
        self::printFullTable( 'Files', WP_CONTENT_DIR, $dir_list, 'wpcontent' );
    }


    /**
     * Root widget display
     * 
     * @since 1.0
     * @access public
     */
    public static function widget2()
    {
        $dir_list = glob( ABSPATH . '/*', GLOB_ONLYDIR );
        self::printFullTable( 'Files', ABSPATH, $dir_list, 'root' );
    }


    /**
     * Used for both Widgets configuration
     * 
     * @since 1.0
     * @access public
     * @uses delete_transient Reset cache
     */
    public static function widget_handle()
    {
        if( 'POST' == $_SERVER['REQUEST_METHOD'] && isset( $_POST[self::TRANSI] ) )
        {
            foreach( self::$what_widget as $wid )
                delete_transient( self::TRANSI . $wid );
        }
        $name = self::TRANSI;
        $cache_msg = count( self::$what_widget ) > 1 ? __( 'Clears both widgets caches', 'mtt' ) : __( 'Clear widget cache', 'mtt' );
        echo "<p><label><input name='$name' id='$name' type='checkbox' value='1' /> Check to empty the cache</label><br /><em style='margin-left: 23px'>$cache_msg</em></p>";
    }


    /**
     * Print widgets contents
     * 
     * @param string    $title
     * @param string    $root           Initial directory to scan
     * @param array     $dir_list       Directory list of folders
     * @param string    $transient_name
     * 
     * @since 1.0
     * @access private
     * @uses set_transient
     */
    private static function printFullTable( $title, $root, $dir_list, $transient_name )
    {
        // $upload_dir 	= wp_upload_dir(); 
        // dirSize($upload_dir['basedir'])
        self::printTable( $title );
        self::printDirectoryList( $dir_list, $transient_name );
        $cache = get_transient( self::TRANSI . $transient_name );
        if( !isset( $cache['root_folder'] ) )
        {
            $root_size = self::dirSize( $root );
            $cache['root_folder'] = $root_size;
            set_transient( self::TRANSI . $transient_name, $cache, self::TIME );
        }
        else
            $root_size = $cache['root_folder'];

        printf(
            '</tbody>
				<tfoot><tr>
					<th class="row-title">%s</td>
					<th>%s</td>
				</tr></tfoot>', __( 'Total', 'mtt' ), $root_size
        );
        echo '</table>';
    }


    /**
     * Prints the start of the table
     * 
     * @param string $title
     * 
     * @since 1.0
     * @access private
     */
    private static function printTable( $title = '' )
    {
        ?>
        <table class="widefat mtt-dash-widget">
            <thead>
                <tr>
                    <th class="row-title"><strong><?php echo $title; ?></strong></th>
                    <th><strong>Size</strong></th>
                </tr>
            </thead>
            <tbody>
        <?php
    }


    /**
     * Prints the list of folders and its sizes
     * 
     * @param array     $directories    List of folders inside a directory
     * @param string    $transient_name
     * 
     * @since 1.0
     * @access private
     */
    private static function printDirectoryList( $directories, $transient_name )
    {
        $count = 0;
        $cache = get_transient( self::TRANSI . $transient_name );
        $transi = array( );
        if( !$cache ):
            foreach( $directories as $dir )
            {
                $alt = (++$count % 2 ) ? 'alternate' : '';
                $name = basename( $dir );
                $size = self::dirSize( $dir );
                $transi[$name] = $size;
                printf(
                    '<tr class="%s">
						<td class="row"><tt>%s</tt></td>
						<td><tt>%s</tt></td>
					</tr>', $alt, $name, $size
                );
            }
            set_transient( self::TRANSI . $transient_name, $transi, self::TIME );
        else:
            unset( $cache['root_folder'] ); // Control value only
            foreach( $cache as $name => $size )
            {
                $alt = (++$count % 2 ) ? 'alternate' : '';
                printf(
                    '<tr class="%s">
						<td class="row">%s</td>
						<td>%s</td>
					</tr>', $alt, $name, $size
                );
            }
        endif;
    }


    /**
     * Iterates through a folder and get its size
     * 
     * From: http://stackoverflow.com/a/18288029
     * 
     * @param string $directory
     * @return string Formatted size
     * 
     * @since 1.0
     * @access private
     */
    private static function dirSize( $directory )
    {
        $size = 0;
        foreach( new RecursiveIteratorIterator( new RecursiveDirectoryIterator( $directory ) ) as $file )
            $size += $file->getSize();

        return self::format_size( $size );
    }


    /**
     * Formats the size into human readable
     * 
     * @param integer $size
     * @return string
     * 
     * @since 1.0
     * @access private
     */
    private static function format_size( $size )
    {
        $units = explode( ' ', 'B KB MB GB TB PB' );
        $mod = 1024;
        for( $i = 0; $size > $mod; $i++ )
            $size /= $mod;

        $endIndex = strpos( $size, "." ) + 3;
        return substr( $size, 0, $endIndex ) . ' ' . $units[$i];
    }
}