post_mime_types Filter not Working in List Mode

Question

I'm using the following code to add new sorting options to my Media Library:

function modify_post_mime_types( $post_mime_types ) {

    $post_mime_types['application/pdf'] = array( __( 'PDFs' ), __( 'Manage PDFs' ), _n_noop( 'PDF <span class="count">(%s)</span>', 'PDFs <span class="count">(%s)</span>' ) );
    $post_mime_types['application/vnd.openxmlformats-officedocument.presentationml.presentation'] = array( __( 'Powerpoints' ), __( 'Manage Powerpoints' ), _n_noop( 'Powerpoints <span class="count">(%s)</span>', 'Powerpoints <span class="count">(%s)</span>' ) );
    $post_mime_types['application/msword, application/vnd.openxmlformats-officedocument.wordprocessingml.document'] = array( __( 'Documents' ), __( 'Manage Documents' ), _n_noop( 'Documents <span class="count">(%s)</span>', 'Documents <span class="count">(%s)</span>' ) );

    return $post_mime_types;

}

add_filter( 'post_mime_types', 'modify_post_mime_types' );

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Which appears to be working great for the JavaScript-enabled "Grid" mode:

However, in the "List" mode, clicking on the entries shows all the extensions/files (even though it is counting them properly) as shown:

Here's the URL it is redirecting to for the PDFs:

wp-admin/upload.php?mode=list&attachment-filter=post_mime_type%3Aapplication%252Fpdf&m=0&filter_action=Filter&s&action=-1&paged=1&action2=-1&affected&_ajax_nonce=093720f202&ps

If I try with the standard Wordpress "Images" filter, it indeed works. Here's the URL it gives for that:

wp-admin/upload.php?mode=list&attachment-filter=post_mime_type%3Aimage&m=0&filter_action=Filter&s&action=-1&paged=1&action2=-1&affected&_ajax_nonce=093720f202&ps

I'm thinking this is perhaps a Wordpress bug, but just making sure if anybody knows anything here.

Answer 1

The problem lies in the attachment-filter= URL parameter. The slash between application/pdf (or else) is being escaped twice. When you replace the %252F with a slash or %2F the filter will work.

The first escaping (/ becomes %2F) happens when WP is building the selectbox containing the mime types. The second one (%2F becomes %252F) is performed by the browser.

The easiest Solution would be to manually urldecode the URL param somewhere in PHP:

if ( isset( $_GET['attachment-filter'] ) )
    $_GET['attachment-filter'] = urldecode($_GET['attachment-filter']);

Update: There is a WP core ticket on that issue: https://core.trac.wordpress.org/ticket/30123

Once this gets fixed, the answer above will be obsolete.