How to use attachment_fields_to_save filter in WordPress

attachment_fields_to_save filter

Using the `attachment_fields_to_save` filter is quite straightforward. First, you need to register it using `add_filter`. You can include this code in the `functions.php` file of your activated theme or in a custom WordPress Plugin.

Creating a custom WordPress Plugin for using hooks is often better, as it ensures that nothing breaks when you update your WordPress Theme in the future.

Here’s a detailed example: we have defined a function `weplugins_modify_attachment_fields_to_save_defaults` which takes 2 parameters. We then registered it using `add_filter`. The first parameter `attachment_fields_to_save` is the name of the hook, the second parameter `weplugins_modify_attachment_fields_to_save_defaults` is the function that needs to be called. The third parameter is the priority of calling the hook if the same hook is used multiple times, and the last parameter is the number of arguments (if any) to be passed to the registered function.

Sometimes, you may need to remove a registered hook, and you can use `remove_filter` to remove the `attachment_fields_to_save` filter.

Parameters

Below are the 2 parameters required to use this hook:

• $post: (array) An array of post data.
• $attachment: (array) An array of attachment metadata.

Live Examples

Example 1: Inserting a Custom Default Caption

In this example, we insert a custom default caption for images.

    function weplugins_insert_custom_default_caption( $post ) {
        if ( 'image' === substr( $post['post_mime_type'], 0, 5 ) ) {
            if ( 0 === strlen( trim( $post['post_title'] ) ) ) {
                $post['post_title'] = preg_replace( '/.w+$/', '', basename( $post['guid'] ) );
                $post['errors']['post_title']['errors'][] = __( 'Empty Title filled from filename.' );
            }
             // captions are saved as the post_excerpt, so we check for it before overwriting
            // If no captions were provided by the user, we fill it with our default
            if ( 0 === strlen( trim( $post['post_excerpt'] ) ) ) {
                $post['post_excerpt'] = 'Default Caption';
            }
        }
        return $post;
    }
    add_filter( 'attachment_fields_to_save', 'weplugins_insert_custom_default_caption', 10, 2 );
    

Example 2: Modifying Attachment Fields

In this example, we modify the attachment fields to save.

    function weplugins_modify_attachment_fields_to_save_defaults( $post, $attachment ) {
        // Update the $post variable according to your website requirements and return this variable.
        // You can modify the $post variable conditionally too if you want.
        return $post;
    }
    // Add the filter
    add_filter( 'attachment_fields_to_save', 'weplugins_modify_attachment_fields_to_save_defaults', 10, 2 );
    

Example 3: Removing a Hook Callback

To remove a hook callback, use the example below:

    remove_filter( 'attachment_fields_to_save', 'weplugins_modify_attachment_fields_to_save_defaults', 10, 2 );
    

Make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.

Contact Us

If you need any customization or are having trouble using this hook, please contact our WordPress Development Team and we’d be happy to assist you.