WordPress Programming Shortcuts and Tricks

I’ve spent quite a bit of time programming in WordPress, somewhere around 6 years to be exact.  Over the time I’ve developed a lot plugins and themes, ranging from minor theme updates, to plugin customizations, automation, a full fledged CRM, WP-Invoice, WP-Property, etc.

In any case, here are some tips and tricks that I use quite often when it comes to plugin development.

Inserting Scripts and Styles into Backend Pages

This is the method I use to quickly setup a backend page and insert the scripts:

// Call my_class::my_class() on WordPress init hook
add_action("init", create_function('', 'new my_class;'));

class my_class {

 /**
 * Registers styles and loads my_class::admin_menu() into WordPress' admin_menu hook
 *
 * @uses wp_register_style()
 * @uses wp_register_script()
 * @uses add_action()
 */    
 function my_class() {

     // Define path
     define('WPP_URL', WP_PLUGIN_URL . '/wp-properties');

     // Register styles ands cripts early on so they can be loaded later on specific pages
     wp_register_style('jquery-fancybox-css',
        WPP_URL. '/third-party/fancybox/jquery.fancybox-1.3.1.css'
     );

    wp_register_script('jquery-fancybox',
        WPP_URL. '/third-party/fancybox/jquery.fancybox-1.3.1.pack.js',
        array('jquery'), '1.7.3'
    );

    // Call my_class::admin_menu() function;
    add_action('admin_menu', array('my_class', 'admin_menu'));

 }

 /**
 * Creates a page called "Slideshow" under the gallery and loads scripts and styles.
 *
 * add_submenu_page() returns a string which is used by WP as a "slug" for the page we added.
 * We add an action to "'admin_print_scripts-' . $slideshow_page", which is only called on our slideshow page.
 *
 * Usually I see developers calling another function that will enqueue scripts and styles, but
 * I prefer to keep the function count down whenever possible, and choose to  use create_function()
 * to return wp_enqueue_script() and wp_enqueue_style() into the header of admin_print_scripts-' . $slideshow_page
 *
 * @uses add_submenu_page()
 * @uses add_action()
 */    
 function admin_menu() {

 // Add submenu page under "Media Galllery"
 $slideshow_page = add_submenu_page(
    'upload.php',
    "Slideshow",
    "Slideshow",
    10,
    'slideshow',
    array('wpp_slideshow', 'page'
 )); 

 // Load FancyBox JS slideshow page
add_action('admin_print_scripts-' . $slideshow_page, create_function('', "
    wp_enqueue_script('jquery-fancybox');
    wp_enqueue_script( 'jquery-ui-sortable');
"));

// Load FancyBox CSS slideshow page
add_action('admin_print_styles-' . $slideshow_page, create_function('', "
    wp_enqueue_style('jquery-fancybox-css');
"));

 }
}

I realize create_function() is slower than using real functions, I haven’t done any benchmarking to see how much slower, but I have a feeling that when used in this manner the performance degradation is nominal.