Add image to media library from URL in uploads directory

Question

The plugin "Video Embed & Thumbnail Generator" does a great job of generating thumbnails from videos. It saves the thumbnail URL as metadata for the attachment. The thumbnail gets added to the uploads directory. Is there a way to take this image and add it to the media library so i can pass the image through the image_downsize function to create thumbnail of a different size?

wp_insert_attachment looks like it needs a path to a file and not a URL, or am i mistaken? how can i add a URL to the media library?

this is possibly a duplicate of How can I get an image from the uploads dir and enter it in the media library? but that never got any answers.

Answer 1

If the image is in the content source you can extract it and use media_sideload_image(); to import it into the media library.

This code sample is from my plugin Media Tools. Which has does this via a admin page via ajax. It also sets the extracted image as the featured image for the post. The post id is being passed to this function via ajax. To look at the complete code see: http://plugins.trac.wordpress.org/browser/media-tools/trunk/media-tools.php?rev=581988

   function process_image( $post_id ) {
        $response = '';
        $error = 0;
        $post = get_post( $post_id );
        $img = $this->extract_image( $post );
        if( empty( $img ) ) {
            $response .=  'No images found <br>';
            die( sprintf( $response . '<br>Media tool complete (Post ID %1$s) in %2$s seconds. %3$d errors', esc_html( $post->ID ), timer_stop(), $error = $error  > 0 ? $error : 'no' ) );
         }
        /** @var $file string or WP_Error of image attached to the post  */
        $file = media_sideload_image( $img, (int)$post->ID );
        if ( is_wp_error( $file ) ) {
            $response .= '<span style="color:red">Upload Error: Could not upload image. Check for malformed img src url</span><br>';
            $error++;
        } else {

         $atts = $this->get_attach( $post->ID );
         foreach ( $atts as $a ) {
             $img = set_post_thumbnail( $post->ID, $a['ID'] );
             if ( $img ) {
                  $thumb = wp_get_attachment_thumb_url( $a['ID'] );
                  $response .= '<img src="'.esc_url( $thumb ).'" /><br>';
                  $response .= '<a href="'.wp_nonce_url( get_edit_post_link( $a['ID'], true ) ).'" >'.get_the_title( $a['ID'] ).'</a>  Set as Featured Image</p><br>';
                        }
                    }
                    unset( $atts );
                    unset( $a );
                }
            die( sprintf( $response.'<br>Media tool complete (Post ID %1$s) in %2$s seconds. %3$d errors', esc_html( $post->ID ), timer_stop(), $error = $error > 0 ? $error : 'no' ) );
    }


    /**
     * Extracts the first image in the post content
     * @param object $post the post object
     * @return bool|string false if no images or img src
     */
    function extract_image( $post ) {
        $html = $post->post_content;
        if ( stripos( $html, '<img' ) !== false ) {
            $regex = '#<\s*img [^\>]*src\s*=\s*(["\'])(.*?)\1#im';
            preg_match( $regex, $html, $matches );
            unset( $regex );
            unset( $html );
            if ( is_array( $matches ) && ! empty( $matches ) ) {
                return  $matches[2];

            } else {
                return false;
            }
        } else {
            return false;
        }
    }

    /**
     * Queries for attached images
     * @param int $post_id The post id to check if attachments exist
     * @return array|bool The 1st attached on success false if no attachments
     */
    function get_attach( $post_id ) {
        return get_children( array (
                'post_parent'    => $post_id,
                'post_type'      => 'attachment',
                'post_mime_type' => 'image',
                'posts_per_page'  => (int)1
            ), ARRAY_A );
    }

Answer 2

here are the pertinant parts that i changed from the kg_video_attachment_fields_to_save() function which filters attachment_fields_to_save:

    $thumb_url = $attachment['kgflashmediaplayer-poster'];

    //insert the $thumb_url into the media library if it does not already exist
    if ( ! ($thumb_id = get_attachment_id_from_src( $thumb_url ) ) ) {

        $post_id = $post['ID'];
        $desc = $attachment['post_title'] . ' thumbnail';

        //is image in uploads directory?
        $upload_dir = wp_upload_dir();

        if ( FALSE !== strpos( $url, $upload_dir['baseurl'] ) ) {
            $wp_filetype = wp_check_filetype(basename($thumb_url), null );
            $filename = preg_replace('/\.[^.]+$/', '', basename($thumb_url));

            $attachment = array(
               'guid' => $thumb_url, 
               'post_mime_type' => $wp_filetype['type'],
               'post_title' => $desc,
               'post_content' => '',
               'post_status' => 'inherit'
            );
            $thumb_id = wp_insert_attachment( $attachment, basename($thumb_url), $post_id );
            // you must first include the image.php file
            // for the function wp_generate_attachment_metadata() to work
            require_once(ABSPATH . 'wp-admin/includes/image.php');
            $attach_data = wp_generate_attachment_metadata( $thumb_id, basename($thumb_url) );
            wp_update_attachment_metadata( $thumb_id, $attach_data );
        } else { //not in uploads so we'll have to sideload it
            $tmp = download_url( $thumb_url );

            // Set variables for storage
            // fix file filename for query strings
            preg_match('/[^\?]+\.(jpg|JPG|jpe|JPE|jpeg|JPEG|gif|GIF|png|PNG)/', $thumb_url, $matches);
            $file_array['name'] = basename($matches[0]);
            $file_array['tmp_name'] = $tmp;

            // If error storing temporarily, unlink
            if ( is_wp_error( $tmp ) ) {
                @unlink($file_array['tmp_name']);
                $file_array['tmp_name'] = '';
            }

            // do the validation and storage stuff
            $thumb_id = media_handle_sideload( $file_array, $post_id, $desc );

            // If error storing permanently, unlink
            if ( is_wp_error($thumb_id) ) {
                @unlink($file_array['tmp_name']);
                return $thumb_id;
            }

            if ( $local_src = wp_get_attachment_url( $thumb_id ) ) {
                update_post_meta($post['ID'], '_kgflashmediaplayer-poster', $local_src);
            }

        } //end sideload

    } //end get_attachment_id_from_src

    if(!is_wp_error($thumb_id)) {
        $thumb_id = intval( $thumb_id );
        update_post_meta($post['ID'], '_kgflashmediaplayer-poster-id', $thumb_id);
    } 

and the video's custom thumbnail ID is now stored in the meta field: _kgflashmediaplayer-poster-id

function get_attachment_id_from_src ($image_src) {
    global $wpdb;

    $query = "SELECT ID FROM {$wpdb->posts} WHERE guid='$image_src'";
    $id = $wpdb->get_var($query);
    return $id;

}

i do not love the get_attachment_id_from_src() but there is no built-in way to do this. i should add in a check so that if the current src is the same as the old source, this query won't need to run. the embedder plugin creates many potential thumbnails for each video and there is no need to insert them all into the media library.... so this fires whenever a media attachment is saved and should cover images that are already in the media library, images that are in the media directory but not in the library and images on other servers (which get sideloaded in, and the URL is adjusted to the new local url)