One thing I’ve found frustrating is that there doesn’t seem to be an easy way of getting a category (or other term) ID. This little snippet will add it to the “quick actions” that appear when you mouseover a term’s row.
add_filter( "tag_row_actions", 'add_cat_id_to_quick_edit', 10, 2 );
function add_cat_id_to_quick_edit( $actions, $tag ) {
$actions['cat_id'] = 'ID: '.$tag->term_id;
return $actions;
}
I’ll leave the ‘why’ to you, but here’s the ‘how’
add_filter( 'media_upload_tabs', 'no_media_library_tab' );
function no_media_library_tab( $tabs ) {
unset($tabs['library']);
return $tabs;
}
Okay, one possible reason would be that you want to restrict users from accessing media that’s been attached to another post.
Are the built in profile fields not as extensive as you’d like? That can be fixed! The following code will add a field (“greeting”) to the “Personal Options” section as well as another (“phone number”) to the “Contact Info” section. Of course, neither of those would be useful if the data wasn’t saved, so that’s in the code too.
add_action( 'personal_options_update', 'save_custom_profile_fields' );
add_action( 'edit_user_profile_update', 'save_custom_profile_fields' );
function save_custom_profile_fields( $user_id ) {
update_user_meta( $user_id, 'phone_number', $_POST['phone_number'], get_user_meta( $user_id, 'phone_number', true ) );
update_user_meta( $user_id, 'greeting', $_POST['greeting'], get_user_meta( $user_id, 'greeting', true ) );
}
add_filter( 'user_contactmethods', 'add_contact_option', 10, 2 );
function add_contact_option( $user_contactmethods, $user ) {
$user_contactmethods['phone_number'] = 'Phone Number';
return $user_contactmethods;
}
add_action( 'personal_options', 'add_profile_options');
function add_profile_options( $profileuser ) {
$greeting = get_user_meta($profileuser->ID, 'greeting', true);
?><tr>
<th scope="row">Greeting</th>
<td><input type="text" name="greeting" value="<?php echo $greeting; ?>" /></td>
</tr><?php
}
Sometimes, it might be necessary to redirect users to some page other than the dashboard. In the example below, users are redirected to their profile page when they log in.
add_filter( 'login_redirect', 'redirect_to_profile', 10, 2 );
function redirect_to_profile( $redirect_to, $user ) {
return admin_url('profile.php');
}
Maybe you need to add some extra text to the page to explain to a user why they should take a minute to spellcheck their new category or tag. Or perhaps you want to want to encourage them to check if a certain category already exists as a plural or singular from. You can add this extra copy in at least 2 places on the various taxonomy admin pages.
add_action( 'after-' . 'category' . '-table', 'copy_below_table' );
function copy_below_table( $taxonomy ) {
echo '<p>Lorem ipsum</p>';
}
add_action( 'category' . '_pre_add_form', 'copy_above_form' );
function copy_above_form( $taxonomy ) {
echo '<p>Dolor sit amet</p>';
}
Perhaps you need to provide a little extra instruction about the Featured Image meta box. It doesn’t take much to add your own text to that box:
add_filter( 'admin_post_thumbnail_html', 'add_featured_image_instruction');
function add_featured_image_instruction( $content ) {
return $content .= '<p>The Featured Image is an image that is chosen as the representative image for Posts or Pages. Click the link above to add or change the image for this post. </p>';
}
If you need to add a simple warning or error notice to the WordPress admin area, or if you just to to make a small announcement to the site users, you can do so pretty easily.
add_action('admin_notices','simple_announcement');
function simple_announcement() {
?><div class="updated">
<p>hello</p>
</div><?php
}
Here’s a bit of code that will allow you to add a footnote to your post – inline. It’s easy enough to add footnotes manually, sure. But where’s the fun in that?
add_shortcode( 'footnote', 'footnote_shortcode' );
function footnote_shortcode( $atts, $content ) {
extract(shortcode_atts( array() , $atts));
global $post;
update_post_meta( $post->ID, '_footnote', $content, get_post_meta( $post->ID, '_footnote', true ) );
return ' <a href="#fn_'.$post->ID.'">*</a> ';
}
add_filter( 'the_content', 'append_footnote' );
function append_footnote($content) {
global $post;
if ( get_post_meta( $post->ID, '_footnote', true ) != '' )
$content .= '<p id="fn_'.$post->ID.'">* '.get_post_meta( $post->ID, '_footnote', true ) .'</p>';
return $content;
}
A footnote could then be added like this:
The moon is 384,403 km [footnote]238,857 miles[/footnote] from the earth.
There might be a better way to append the footnote to the end – so feel free to investigate and improve.
Sometimes, the ability to add multiple categories to a single post can cause problems. Or maybe you’re working with custom taxonomies and you need to make sure only one term is assigned to a post. Assuming you’re creating your own alternative category selection box, you can use this to get red of the default meta box.
add_action('admin_init','remove_cat_box');
function remove_cat_box() {
//args: $categoryslug.'div', $posttype, $location
remove_meta_box('categorydiv', 'post', 'side');
}
For a variety of reasons, you may not be able to add content directly to the WordPress editor. Maybe it’s funky code that’ll get stripped out, or you want a random quote to show up, or it’s some other kind of dynamic content.
That’s what shortcodes are good for! Here’s a simple one that creates a ‘youtube’ shortcode for embedding videos in your post.
add_shortcode( 'youtube', 'youtube_shortcode' );
function youtube_shortcode( $atts ) {
extract( shortcode_atts( array('id' => '', 'width' => 480, 'height' => 390) , $atts ) );
$id = trim($id);
if (empty($id)) return;
return '<iframe title="YouTube video player" width="'. $width .'" height="'. $height .'" src="http://www.youtube.com/embed/'. $id .'" frameborder="0" allowfullscreen></iframe>';
}
Used in your post like this: . The width and height attributes will default to 480 and 390 respectively if not specified in the shortcode. Quotes around the attribute value are not required unless your value has a space.