I have added new mime types with the 'post_mime_types' filter eg. PDF, doc, mp3 etc...

Filtering by custom mime type on the upload.php page in media grid view works as expected but in list view it doesn't.

The problem is that WordPress passes the mime types through urlencode as it builds the html (wp-admin/includes/class-wp-media-list-table.php:73) and so




for the drop down value.

When the filter form is submitted the encoded '/' is ignored and doesn't filter properly.

Changing the '%2F' back to a '/' with JS would work but I'd like to know if anyone has a solution to decode the string before its processed and the page reloaded.

  • The problem is that "/" character is double enconded. First it is encoded for the dropdown value, so "/" becomes "%2F". Then it is encoded again and "%2F" becomes "%252F" in the URL request. "%252F" decodes to "%/", no to "/", and that is because the filter fails. The "/" character should be sent as "%2F". I'm now investigating a solution.
    – cybmeta
    Commented Oct 27, 2014 at 11:58
  • thanks for looking into it @cymeta. I added a bug ticket to the core trac here core.trac.wordpress.org/ticket/30123#ticket
    – chris
    Commented Oct 27, 2014 at 16:11
  • A similar question was posted here.
    – birgire
    Commented Oct 27, 2014 at 17:03

1 Answer 1


Here's a workaround you can put in a plugin or your theme's functions.php file. So far no problems.

* Workaround Bug 30123
* Affects WP 4.0+, should be fixed in WP 4.1
* https://core.trac.wordpress.org/ticket/30123
function bugfix30123__action__admin_init() {
    if ( isset( $_GET['attachment-filter'] ) && is_string( $_GET['attachment-filter'] ) ) {
        $_GET['attachment-filter'] = $_REQUEST['attachment-filter'] = str_replace( '%2F', '/', $_GET['attachment-filter'] );
add_action( 'admin_init', 'bugfix30123__action__admin_init' );

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