The following function checks whether a Gravatar exists for a given email or user ID in WordPress and returns a boolean. Add this code to your theme’s functions.php file:
/**
* Utility function to check if a gravatar exists for a given email or id
* @param int|string|object $id_or_email A user ID, email address, or comment object
* @return bool if the gravatar exists or not
*/
function validate_gravatar($id_or_email) {
//id or email code borrowed from wp-includes/pluggable.php
$email = '';
if ( is_numeric($id_or_email) ) {
$id = (int) $id_or_email;
$user = get_userdata($id);
if ( $user )
$email = $user->user_email;
} elseif ( is_object($id_or_email) ) {
$allowed_comment_types = apply_filters( 'get_avatar_comment_types', array( 'comment' ) );
if ( ! empty( $id_or_email->comment_type ) && ! in_array( $id_or_email->comment_type, (array) $allowed_comment_types ) )
return false;
if ( !empty($id_or_email->user_id) ) {
$id = (int) $id_or_email->user_id;
$user = get_userdata($id);
if ( $user)
$email = $user->user_email;
} elseif ( !empty($id_or_email->comment_author_email) ) {
$email = $id_or_email->comment_author_email;
}
} else {
$email = $id_or_email;
}
$hashkey = md5(strtolower(trim($email)));
$uri = 'http://www.gravatar.com/avatar/' . $hashkey . '?d=404';
$data = wp_cache_get($hashkey);
if (false === $data) {
$response = wp_remote_head($uri);
if( is_wp_error($response) ) {
$data = 'not200';
} else {
$data = $response['response']['code'];
}
wp_cache_set($hashkey, $data, $group = 'has_gravatar', $expire = 60*5);
}
if ($data == '200'){
return true;
} else {
return false;
}
}
Use the function like this:
$author_id = get_the_author_meta( 'ID' );
if (validate_gravatar($author_id)) {...}
For more WordPress tips, see What is WordPress?.
Here is a short snippet that sends an email when you publish a new post on your blog. This code can also work for Custom Post Types.
add_action('future_to_publish', 'send_emails_on_new_event');
add_action('new_to_publish', 'send_emails_on_new_event');
add_action('draft_to_publish' ,'send_emails_on_new_event');
add_action('auto-draft_to_publish' ,'send_emails_on_new_event');
/**
* Send emails on event publication
*
* @param WP_Post $post
*/
function send_emails_on_new_event($post)
{
$emails = "email_1@mail.com, email_2@mail.com"; //If you want to send to site administrator, use $emails = get_option('admin_email');
$title = wp_strip_all_tags(get_the_title($post->ID));
$url = get_permalink($post->ID);
$message = "Link to post: n{$url}";
wp_mail($emails, "New post published: {$title}", $message);
}
The result will look something like:
[Title] New post published: Your Post
Link to post:
http://site.co.il/your-post/
If you want to enable this for a specific Custom Post Type, add a condition inside the function like this:
...
if(get_post_type($post->ID) === 'page') //post, page, attachment or whatever other CPT you may have
{
//use wp_mail() here!
}
...
When a user logs out, WordPress by default sends them back to the login page (wp-login.php). In many cases it makes more sense to redirect them to the site homepage. Here is a snippet that does that:
add_action('wp_logout', function()
{
wp_redirect(get_home_url());
exit;
});
For more on redirects and SEO, see 301 Redirects and Their SEO Importance.
Here is a way to add a class based on the user role in the WordPress admin. Add the following code to your theme’s functions.php file:
add_filter('admin_body_class', function($classes) {
global $current_user;
if(is_array($current_user->roles)) {
foreach($current_user->roles as $role) {
$classes .= "user-role-{$role} ";
}
}
return rtrim($classes);
});
The result will look something like:
<body class="... user-role-administrator ...">
This uses the body_class filter. Learn more in WordPress Hooks Explained.
A short snippet that lets you change the order of the menu in the WordPress dashboard. Simply choose the order you want in the $reordered_items array. You can use var_dump($menu_order) to find all menu items.
Items will appear under the top-level item (Dashboard).
add_filter('menu_order', 'reorder_admin_menu', 999);
/**
* Reorders admin menu to match the wanted order
*
* @param $menu_order
* @return mixed
*/
function reorder_admin_menu($menu_order) {
$reordered_items = array(
'edit.php?post_type=page',
'edit.php'
);
$reordered_items_insertion_point = 'index.php';
$filtered_menu_order = array_diff($menu_order, $reordered_items);
$new_menu_order = array();
foreach($filtered_menu_order as $menu_item) {
$new_menu_order[] = $menu_item;
if($menu_item === $reordered_items_insertion_point) {
$new_menu_order = array_merge($new_menu_order, $reordered_items);
}
}
return $new_menu_order;
}
This uses a WordPress filter. Learn more in WordPress Hooks Explained.
Example of adding a CSS file from your theme to the WYSIWYG editor of the Advanced Custom Fields plugin. The code below also works on the frontend if you use the acf_form() function.
add_filter( 'tiny_mce_before_init', function($mce_init) {
$content_css = get_stylesheet_directory_uri() . '/your-custom-css.css';
if (isset($mce_init[ 'content_css' ])) {
$mce_init[ 'content_css' ] = "{$mce_init['content_css']},{$content_css}";
}
return $mce_init;
});
The following snippet is taken from WooCommerce documentation and does exactly what you think. Add this snippet to your functions.php file to add a new country to the WooCommerce countries list:
function woo_add_my_country( $country ) {
$country["AE-DU"] = 'Dubai';
return $country;
}
add_filter( 'woocommerce_countries', 'woo_add_my_country', 10, 1 );
If you look at the source of paginated pages on your blog, you will see they all share the same title tag. To avoid duplicate <title> tags, add the page number to the end of the tag. You can do this (assuming you use WordPress SEO by Yoast) by adding the following code to your functions.php file:
function change_yoast_title($title) {
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
if ( is_paged() ) {
return $title . ' - Page ' . $paged;
}
else {
return $title;
}
}
add_filter('wpseo_title','change_yoast_title');
If you want to remove canonical URLs from search results in WordPress, and you use WordPress SEO by Yoast, add the following filter to your child theme’s functions.php file:
function yoast_remove_canonical_search( $canonical ) {
if( is_search() ) {
return false;
} else {
return $canonical;
}
}
add_filter('wpseo_canonical', 'yoast_remove_canonical_search');
More on what a canonical tag is and how to use it in the post What is a Canonical Tag and how to use it?
WordPress comments come by default with a field named “Website” or “URL”. If you want to remove this field, whether for design or to remove a field that is usually unnecessary, use the following snippet in functions.php:
function savvy_disable_comment_url($fields) {
unset($fields['url']);
return $fields;
}
add_filter('comment_form_default_fields','savvy_disable_comment_url');
This uses a WordPress filter. Learn more in WordPress Hooks Explained.
