Archives: Snippets | Page 8

This snippet does something neat – it adds an option under the Settings menu with a link named “All Settings” that shows a full list of all settings in the database related to your WordPress site.

The code below shows this option only to site administrators and hides it from other users.

function all_settings_link() {
   add_options_page(__('All Settings'), __('All Settings'), 'administrator', 'options.php');
}

add_action('admin_menu', 'all_settings_link');

For a broader WordPress overview, see What is WordPress?.

WordPress has a built-in function to check if you are on a specific page:

if ( is_page(5) ) {
        // do some stuff
    }

Or whether the page is a child of a specific page:

if ( $post->post_parent == '5' ) {
        // do some stuff
    }

But there is no built-in WordPress function that checks both conditions together, and this is very useful. For example – if we want to load a JS file for a videos page and all pages under it…

The following function (add to functions.php) creates a new logical function for this check:

function is_tree($the_page_id) {   
    global $post;         

    if(is_page()&&($post->post_parent==$the_page_id||is_page($the_page_id))) 
       return true;   
    else 
       return false;   
    };

Usage

if (is_tree(5)) {
        // do some stuff
    }

For more on WordPress page templates, see WordPress Template Hierarchy.

The following code lets you set the default post status on your WordPress site to Private.

<?php 
function default_posts_to_private()
{
	global $post;

	if ( $post->post_status == 'publish' ) {
		$visibility = 'public';
		$visibility_trans = __('Public');
	} elseif ( !empty( $post->post_password ) ) {
		$visibility = 'password';
		$visibility_trans = __('Password protected');
	} elseif ( $post->post_type == 'post' && is_sticky( $post->ID ) ) {
		$visibility = 'public';
		$visibility_trans = __('Public, Sticky');
	} else {
		$post->post_password = '';
		$visibility = 'private';
		$visibility_trans = __('Private');
	} 
?>

	<script type="text/javascript">
		(function($){
			try {
				$('#post-visibility-display').text('<?php echo $visibility_trans; ?>');
				$('#hidden-post-visibility').val('<?php echo $visibility; ?>');
				$('#visibility-radio-<?php echo $visibility; ?>').attr('checked', true);
			} catch(err){}
		}) (jQuery);
	</script>
	<?php
add_action( 'post_submitbox_misc_actions' , 'default_posts_to_private' );

This uses a WordPress hook. Learn more in WordPress Hooks Explained.

When working on a project that requires creating multiple taxonomies, it makes sense to use this function rather than creating a separate function for each taxonomy. Put each taxonomy’s parameters in the array and the function handles the rest:

<?php
/**
 * Register Multiple Taxonomies
 *
 */
function register_multiple_taxonomies() {
    $taxonomies = array(
        array(
            'slug'         => 'job-department',
            'single_name'  => 'Department',
            'plural_name'  => 'Departments',
            'post_type'    => 'jobs',
            'rewrite'      => array( 'slug' => 'department' ),
        ),
        array(
            'slug'         => 'job-type',
            'single_name'  => 'Type',
            'plural_name'  => 'Types',
            'post_type'    => 'jobs',
            'hierarchical' => false,
        ),
        array(
            'slug'         => 'job-experience',
            'single_name'  => 'Min-Experience',
            'plural_name'  => 'Min-Experiences',
            'post_type'    => 'jobs',
        ),
    );
    foreach( $taxonomies as $taxonomy ) {
        $labels = array(
            'name' => $taxonomy['plural_name'],
            'singular_name' => $taxonomy['single_name'],
            'search_items' =>  'Search ' . $taxonomy['plural_name'],
            'all_items' => 'All ' . $taxonomy['plural_name'],
            'parent_item' => 'Parent ' . $taxonomy['single_name'],
            'parent_item_colon' => 'Parent ' . $taxonomy['single_name'] . ':',
            'edit_item' => 'Edit ' . $taxonomy['single_name'],
            'update_item' => 'Update ' . $taxonomy['single_name'],
            'add_new_item' => 'Add New ' . $taxonomy['single_name'],
            'new_item_name' => 'New ' . $taxonomy['single_name'] . ' Name',
            'menu_name' => $taxonomy['plural_name']
        );
        
        $rewrite = isset( $taxonomy['rewrite'] ) ? $taxonomy['rewrite'] : array( 'slug' => $taxonomy['slug'] );
        $hierarchical = isset( $taxonomy['hierarchical'] ) ? $taxonomy['hierarchical'] : true;
    
        register_taxonomy( $taxonomy['slug'], $taxonomy['post_type'], array(
            'hierarchical' => $hierarchical,
            'labels' => $labels,
            'show_ui' => true,
            'query_var' => true,
            'rewrite' => $rewrite,
        ));
    }
    
}
add_action( 'init', 'register_multiple_taxonomies' );

In my last project I needed to split the WordPress loop into groups of three posts – so if there are nine posts, every three would be wrapped in a div. You can do this using a counter and checking inside the loop whether it is a multiple of 3, and if so, closing the div. To change the number of posts per group, change the number 3 on line 14. Here is the code:

<?php if ( have_posts() ) :
	$i = 0;
	while ( have_posts() ) : the_post();
		if ( $i % 3 == 0 ) { ?>
			<div>
	<?php } ?>
			<div class="single_item">
				<h2>
					<a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?>
					</a>
				</h2>
			</div>
	<?php $i ++;
		if ( $i % 3 == 0 ) { ?>
			</div>
	<?php } ?>

	<?php endwhile; ?>
	<?php
	if ( $i % 3 != 0 ) { ?>
		</div>
	<?php } ?>

<?php endif; ?>

For more loop customization, see Remove a Category from the Main Loop.

There are situations (quite common) where you want to limit WordPress search to titles only and not the post body text. To do this, add the following code to your functions.php file. For a more powerful search engine, see Relevanssi Better Search. Note that this function also applies to search performed from the WordPress dashboard.

/**
 * Search SQL filter for matching against post title only.
 *
 * @param   string      $search
 * @param   WP_Query    $wp_query
 */
function wpse_11826_search_by_title( $search, $wp_query ) {
    if ( ! empty( $search ) && ! empty( $wp_query->query_vars['search_terms'] ) ) {
        global $wpdb;

        $q = $wp_query->query_vars;
        $n = ! empty( $q['exact'] ) ? '' : '%';

        $search = array();

        foreach ( ( array ) $q['search_terms'] as $term )
            $search[] = $wpdb->prepare( "$wpdb->posts.post_title LIKE %s", $n . $wpdb->esc_like( $term ) . $n );

        if ( ! is_user_logged_in() )
            $search[] = "$wpdb->posts.post_password = ''";

        $search = ' AND ' . implode( ' AND ', $search );
    }

    return $search;
}

add_filter( 'posts_search', 'wpse_11826_search_by_title', 10, 2 );

Sometimes you need to add a specific attribute to an image. You can do this quickly using the the_post_thumbnail function. The following snippet adds the itemprop="image" attribute to images, but you can also use it to add class, alt, title, etc.

the_post_thumbnail( 'thumbnail', array('itemprop'=>'image') );

For more on WordPress images, see Image Sizes in WordPress.

When you write a post, it is automatically saved as a draft every minute. If your browser crashes this lets you recover your work. You can change the time between saves by adding the following line to your wp-config.php file:

define( 'AUTOSAVE_INTERVAL', X);

Where X is the number of seconds between saves.

For more wp-config.php settings, see Optimize WordPress Configuration via wp-config.php.

How to change the position of the admin bar in WordPress?

More than once the WordPress admin bar has bothered me because it hid menus that were set to position:fixed in CSS. A few lines in functions.php and the admin bar moves to the bottom of the page:

<?php
function fb_move_admin_bar() { ?>
	<style type="text/css">
		body {
			margin-top: -28px;
			padding-bottom: 28px;
		}
		body.admin-bar #wphead {
			padding-top: 0;
		}
		body.admin-bar #footer {
			padding-bottom: 28px;
		}
		#wpadminbar {
			top: auto !important;
			bottom: 0;
		}
		#wpadminbar .quicklinks .menupop ul {
			bottom: 28px;
		}
	</style>
<?php }
add_action( 'admin_head', 'fb_move_admin_bar' );
add_action( 'wp_head', 'fb_move_admin_bar' );

For safe WordPress customizations, see What Are Child Themes and How to Use Them.