hearvox/wp-insert-attach-media.php

## wp-insert-attach-media.php
<?php
/**
 * Add files to Media Library; attach files to posts.
 *
 * This is for adding files to Media Library already in /uploads/.
 * If files are elsewhere, adapt script.
 *
 * Attempts to attach file to post:
 * Searches thru post content for the filename.
 * If a post is found, then uses post ID and publish-date
 * as attachemnt's parent ID and upload-date.
 * If no post found, parent ID set to 0 and date to file mod date.
 *
 * See this gist to generate list fo files:
 * @link https://gist.github.com/hearvox/b5f3b70bcb92170ff091486224c9a2ad
 * Based on example at:
 * @link https://developer.wordpress.org/reference/functions/wp_insert_attachment/
 */

// Array of GUIDs of files to add to Media Library.
$files = array(
    '2010/01/example-file.pdf',
    '2010/01/next-example-file.pdf',
    '2010/02/nother-example-file.pdf',
);
/* UNCOMMENT foreach() TO RUN SCRIPT */
// Traverse array of file names.
foreach ( $files as $filename ) {
    //  Default attachment meta.
    $filedate  = date( 'Y-m-d H:i:s' );
    $parent_id = 0;
    $attach_id = 0;

    // Get the path to the file
    $filepath = $wp_upload_dir['path'] . '/' . $filename;

    // Check for file.
    if ( file_exists( $filepath ) ) {
        // Check the type of file. We'll use this as the 'post_mime_type'.
        $filetype = wp_check_filetype( basename( $filename ), null );

        // Attach file to post: Search for filename in content.
        $args = array(
            'post_type'      => 'post',
            'fields'         => 'ids',
            'posts_per_page' => 1,
            's'              => $filename,
        );
        $query = new WP_Query( $args );

        // If post found, get post's ID and date (to set attachment's parent and date).
        if ( isset( $query->posts[0] ) ) {
            $parent_id = $query->posts[0];
            $filedate  = get_the_date( 'Y-m-d H:i:s', $parent_id );
        } else {
            // Get the file's modification timestamp.
            $filemtime = filemtime( $filepath );
            $filedate  = date( 'Y-m-d H:i:s', $filemtime );
        }


        // Prepare an array of post data for the attachment.
        $attachment = array(
            'guid'           => $wp_upload_dir['url'] . '/' . basename( $filename ),
            'post_mime_type' => $filetype['type'],
            'post_title'     => preg_replace( '/\.[^.]+$/', '', basename( $filename ) ),
            'post_content'   => '',
            'post_date'      => $filedate,
            'post_status'    => 'inherit'
        );
       // Make sure that this file is included, as wp_generate_attachment_metadata() depends on it.
       require_once( ABSPATH . 'wp-admin/includes/image.php' );

        // Insert the attachment, generate the metadata for the attachment,
        // and update the database record.
        // UNCOMMENT these 3 lines to run:

        // $attach_id = wp_insert_attachment( $attachment, $filename, $parent_id );
        // $attach_data = wp_generate_attachment_metadata( $attach_id, $filename );
        // wp_update_attachment_metadata( $attach_id, $attach_data );

        // Prints results for tests and reference.
        echo "$filename | <a href='/?p=$attach_id'>$attach_id</a> | $filedate | $parent_id<br >";
    } else { // Not inserted: file doesn't exist at specified path.
        echo "$filename | 0<br >";
    }
}