My Monkey Do

A Log of Coding Solutions

wordpress

Where is wp_capabilities?

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Problem

After creating a user with a certain role I need to do a custom sql query where it only selected users of a specific role.  This failed to find anything:

select u.ID, u.display_name, u.user_login
from $wpdb->users as u
inner join $wpdb->usermeta as umr
on ( umr.user_id = u.ID )
and ( umr.meta_key = 'wp_capabilities' )

$user = get_userinfo( $user_id );
var_dump( $user->roles );

get_userinfo got the right role, so saving was correct.

$caps = get_user_meta( $user_id, 'wp_capabilities' );
var_dump( $caps );

$caps was null.  weird.

 

Solution

You learn something new everyday.  After looking through the WordPress core code I found that the meta key is actually composed of the table prefix and ‘capabilities’.  So the correct query would be:

select u.ID, u.display_name, u.user_login
from $wpdb->users as u
inner join $wpdb->usermeta as umr
on ( umr.user_id = u.ID )
and ( umr.meta_key = '" . $wpdb->prefix . "capabilities' )

WordPress REST API schema property format: email

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Problem:  When setting a property type to ’email’ like so:

$schema = array(
'$schema' => 'http://json-schema.org/schema#',
'title' => 'user',
'type' => 'object',
'properties' => array(
'email' => array(
'description' => __( 'The optional email address for the something.' ),
'type' => 'string',
'format' => 'email',
'context' => array( 'edit' ),
'required' => false,
) )

);

WordPress checks if it’s an email like it should, but it does this even if an empty string is passed.  If this needs to be an optional field, the only way I see around it is to not set the format to email.

WordPress 4.6 crashed my site

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Fatal error: Cannot redeclare the_post_thumbnail_caption() (previously declared in ….

This error occurs because the_post_thumbnail_caption is a new function in WordPress 4.6.  However, people have been using this function for over 5 years now.  How?  Stackoverflow and other WordPress forums are flooded with questions asking how they can print out the thumbnail caption.  Since this wasn’t a built-in function before, the answer was to make your own function which was appropriately named the_post_thumbnail_caption.

Many theme authors, myself included, are now guilty of simply copy-pasting this function without adding their own theme prefix.  To avoid errors like this, functions within a theme should be prefixed with something unique to the theme like “mymonkeytheme_the_post_thumbnail_caption”.

If you have this error, contact your theme author and ask them to fix the theme.

 

WordPress the_title filter changed in nav menus

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I haven’t had time to look into the exact reason or the exact version this changed, but as of at least WordPress version 4.5.2 the nav menu uses the_title multiple times for one item.

For example if your theme used something like this:


function menu_title_filter( $title ) {
return $title . ' | ';
}
add_filter( 'the_title', 'menu_title_filter' );

It would have one ” | ” after each menu title in previous versions, but in WordPress 4.5 ish it would show two ” | “.  Again, haven’t looked at the exact cause that changes this, but the solution is to check if the item you’re looking at is a nav_menu_item:

function menu_title_filter( $title, $id ) {
$item = get_post( $id );
if ( $item->post_type != 'nav_menu_item') return $title;
return $title . ' | ';
}
add_filter( 'the_title', 'menu_title_filter', 10, 2 );

Speed up WP_Query

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In WordPress, when a query does not need paging and you only want a limited amount of results, like the last 5 posts, set the ‘no_found_rows’ parameter to true.  This prevents WordPress from doing additional work in counting the total matched rows, thus speeding up your query.

This is already built into get_posts, but not WP_Query.

Example:

$last_5_query = WP_Query( array( ‘no_found_rows’=> true, ‘posts_per_page’=>5 ) );

Disable Responsive Images in WordPress

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In WordPress 4.4 images are displayed with the srcset attribute.  This attribute allows the browser to select alternative images for best viewing.  Sometimes though this may not be wanted as the image being displayed is the only image you want to show for all users.

To not have any srcset images, use the following:

add_filter( ‘wp_calculate_image_srcset_meta’, ‘__return_null’ );

For other filters new to WordPress 4.4, you can visit the blog post:

Responsive Images in WordPress 4.4

 

One user had a problem with the images in the srcset not having the https protocol and causing security warnings.  This stack overflow post resolves that:

http://wordpress.stackexchange.com/questions/211375/how-do-i-disable-responsive-images-in-wp-4-4