wp_generate_attachment_metadata returning an empty array
I've had a similar problem where mime type was missing. Since I use only one mime type, it was fixed by
'post_mime_type' => 'image/jpeg'After that, it was still not updating the metadata, but forcing the update with "wp_update_attachment_metadata" solved the problem:
$attach_data = wp_generate_attachment_metadata($attach_id, $file_path);wp_update_attachment_metadata($attach_id, $attach_data);
This is, what finally fixed it for me:
apply_filters('wp_handle_upload', array( 'file' => $file_path, 'url' => $file_url, 'type' => $file_type), 'upload');Explanation: I'm not quite sure why this fixed the error for me, but I assume that this either has something to do with plugins using the wp_handle_upload hook or that the filters add meta-data to the attachment, which otherwise would be missing in the wp_generate_attachment_metadata function.
Full function:
function add_to_media_lib($file_url, $file_path, $parent_post_id){require_once(ABSPATH . 'wp-admin/includes/image.php');require_once(ABSPATH . 'wp-admin/includes/file.php');// Check the type of tile. We'll use this as the 'post_mime_type'.$file_type = wp_check_filetype(basename($file_url), null);// Get the path to the upload directory.$wp_upload_dir = wp_upload_dir();// Prepare an array of post data for the attachment.$attachment = array( 'guid' => $wp_upload_dir['url'] . '/' . basename($file_url), 'post_mime_type' => $file_type['type'], 'post_title' => preg_replace('/\.[^.]+$/', '', basename($file_url)), 'post_content' => '', 'post_status' => 'inherit', 'post_parent' => $parent_post_id);// Insert the attachment.$attach_id = wp_insert_attachment($attachment, $file_url, $parent_post_id);// apply filters (important in some environments)apply_filters('wp_handle_upload', array('file' => $file_path, 'url' => $file_url, 'type' => $file_type), 'upload');// Generate the metadata for the attachment, and update the database record.if ($attach_data = wp_generate_attachment_metadata($attach_id, $file_path)) { wp_update_attachment_metadata($attach_id, $attach_data);} else { echo '<div id="message" class="error"><h1>Failed to create PDF-thumbnail Meta-Data</h1><pre>' . print_r($attach_data) . '</pre></div>';}return $attach_id;}