March 2011 – trepmal.com

Change which Meta Boxes are Shown or Hidden by Default

If you want to change what meta boxes are shown and hidden by default instead of trying to walk a client through the process of customizing their own screen, you can use this code as a starting point:

add_filter( 'default_hidden_meta_boxes', 'change_default_hidden', 10, 2 );
function change_default_hidden( $hidden, $screen ) {
    if ( 'page' == $screen->id ) {
        $hidden = array_flip($hidden);
        unset($hidden['authordiv']); //show author box
        $hidden = array_flip($hidden);
        $hidden[] = 'pageparentdiv'; //hide page attributes
    }
    return $hidden;
}

Use a Custom Field to Add to the

I needed a very simple way to custom styles or scripts to the <head>, and I didn’t really want to customize the theme.

add_action( 'wp_head', 'wp_head_custom_field' );
function wp_head_custom_field() {
    if ( is_single() ) {
        global $post;
        $html = get_post_meta( $post->ID, 'wp_head', true );
        echo $html;
    }
}

With this, I just needed to add my pre-formatted javascript or css to a custom field called ‘wp_head’ and it would then be added to the <head> just like I needed. I added the is_single() as a precaution.

Swap Color Schemes When Switching Between Network and Site Admins

I wanted to find a way to make it just a little bit more obvious when I switched between the network and site admins. But I didn’t want to have to do a lot of actual customizing. So using built in styles, I found I could just swap the color schemes.

add_action( 'admin_print_styles', 'admin_color_swap', 99 );
function admin_color_swap() {
    if ( is_network_admin() ) {
        global $current_user;
        get_currentuserinfo();
        $selected = $current_user->admin_color;
        $swapped = array( 'fresh' => 'classic', 'classic' => 'fresh' );
        $new = $swapped[$selected];        
        echo '<link rel="stylesheet" type="text/css" href="/wp-admin/css/colors-'.$new.'.css" />';
    }
}

Add Post Options To “Publish” Meta Box

We often add custom meta boxes to a page or post in order to save specific kinds of data. In some cases, the best place to add those fields really isn’t in some box that gets added to the end of the page. The option needs to be in a bit more prominent location.

Fortunately, it’s possible to add text or form elements to the “Publish” meta box.

add_action( 'post_submitbox_misc_actions', 'article_or_box' );
add_action( 'save_post', 'save_article_or_box' );
function article_or_box() {
    global $post;
    if (get_post_type($post) == 'post') {
        echo '<div class="misc-pub-section misc-pub-section-last" style="border-top: 1px solid #eee;">';
        wp_nonce_field( plugin_basename(__FILE__), 'article_or_box_nonce' );
        $val = get_post_meta( $post->ID, '_article_or_box', true ) ? get_post_meta( $post->ID, '_article_or_box', true ) : 'article';
        echo '<input type="radio" name="article_or_box" id="article_or_box-article" value="article" '.checked($val,'article',false).' /> <label for="article_or_box-article" class="select-it">Article</label><br />';
        echo '<input type="radio" name="article_or_box" id="article_or_box-box" value="box" '.checked($val,'box',false).'/> <label for="article_or_box-box" class="select-it">Box</label>';
        echo '</div>';
    }
}
function save_article_or_box($post_id) {

    if (!isset($_POST['post_type']) )
        return $post_id;

    if ( !wp_verify_nonce( $_POST['article_or_box_nonce'], plugin_basename(__FILE__) ) )
        return $post_id;

    if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE ) 
        return $post_id;

    if ( 'post' == $_POST['post_type'] && !current_user_can( 'edit_post', $post_id ) )
        return $post_id;
    
    if (!isset($_POST['article_or_box']))
        return $post_id;
    else {
        $mydata = $_POST['article_or_box'];
        update_post_meta( $post_id, '_article_or_box', $_POST['article_or_box'], get_post_meta( $post_id, '_article_or_box', true ) );
    }

}

What I needed at one time was a way to mark a post that would determine whether it would be displayed in a regular article style, or in a special box style. Nowadays, I can use post formats. But the point is, you could put other options there. Perhaps an expiration date field.

Force the HTML Uploader

If you need to force users to use the HTML uploader, you can do so with this

add_filter( 'flash_uploader', 'force_html_uploader' );
function force_html_uploader( $flash ) {
	remove_action('post-html-upload-ui', 'media_upload_html_bypass' );
	return false;
}

The remove_action() portion removes the “You are using the Browser uploader” text. The rest is what forces the flash setting to be false.

List Category ID in Quick Actions

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;
}

Remove the Media Library Tab

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.

Add Fields to Profile/Edit-User Pages

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
}

Redirect Users at Login

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');
}

Add Copy to the Add New Tag (or other Taxonomy) Page

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>';
}