Export a CSV report of all media in a WordPress Site

csv_media_export.php

<?php
/**
 * Media Library Report class
 *
 * Adds a Media Library Report option to WP Admin / Tools / Export.
 */
class Media_Library_Report {

	/**
	 * Set up all the hooks.
	 *
	 * @return void
	 */
	public function init() {
		add_action( 'export_filters', array( $this, 'add_export_option' ) );
		add_filter( 'export_args', array( $this, 'export_args' ) );
		add_action( 'export_wp', array( $this, 'export' ) );
		add_action( 'admin_init', array( $this, 'register_importer' ) );
	}

	/**
	 * Add an option to export report.
	 */
	public function add_export_option() {
		?>
		<p><label><input type="radio" name="content" value="media-library-report" /> <?php esc_html_e( 'Media Library Report (csv)', 'plugin' ); ?></label></p>
		<?php
	}


	/**
	 * Prevent the normal xml file from loading and set up for the report.
	 *
	 * @param  array $args The export args being filtered.
	 *
	 * @return array
	 */
	public function export_args( $args ) {
		if ( 'media-library-report' === filter_input( INPUT_GET, 'content', FILTER_SANITIZE_STRING ) ) {
			return array( 'media-library-report' => true );
		}

		return $args;
	}

	/**
	 * Get array of arrays to export.
	 *
	 * @return array
	 */
	public function get_media_attachments() {
		$rows = [];
		$query_args = [
			'post_type' => 'attachment',
			'posts_per_page' => '-1',
			'post_status' => 'any',
			'suppress_filters' => false,
		];

		add_filter( 'pre_get_posts', [ $this, 'reset_query' ], 999 );
		$query = new WP_Query( $query_args );
		remove_filter( 'pre_get_posts', [ $this, 'reset_query' ], 999 );

		foreach ( $query->posts as $post ) {
			$rows[] = [
				'post_title' => $post->post_title,
				'post_excerpt' => $post->post_excerpt,
				'post_name' => $post->post_name,
				'ione_image_credit_meta' => get_post_meta( $post->ID, '_image_credit_meta', true ),
				'_wp_attachment_image_alt' => get_post_meta( $post->ID, '_wp_attachment_image_alt', true ),
				'_ione_media_id' => get_post_meta( $post->ID, '_plugin_media_id', true ),
				'_wp_attached_file' => get_post_meta( $post->ID, '_wp_attached_file', true ),
			];
		}
		return $rows;
	}

	/**
	 * Clear out meta queries set elsewhere in the code.
	 *
	 * Can be extended in the future to clear out other modifications to our query.
	 *
	 * @param WP_Query $query Query set in get_media_attachments().
	 */
	public function reset_query( $query ) {
		// Only reset what you have to for this query. May have to var_export to find out what has been added here that should not have been.
		$query->set( 'meta_key', '' );
		$query->set( 'meta_query', new WP_Meta_Query() );
	}

	/**
	 * Do the export.
	 *
	 * @param  array $args The export arguments.
	 */
	public function export( $args ) {
		$this->get_media_attachments();

		if ( ! empty( $args['media-library-report'] ) ) {
			$sitename = sanitize_key( get_bloginfo( 'name' ) ) ?: 'nameless-site';

			$this->do_headers( sprintf( '%s-media-library-report-%s.csv', $sitename, date( 'Y-m-d' ) ) );

			$this->output_array_as_csv( $this->get_media_attachments() );

			exit();
		}
	}

	/**
	 * Set headers including filename.
	 *
	 * @param string $filename Export csv with this filename.
	 */
	public function do_headers( $filename ) {
		header( 'Content-Type: text/csv; charset=utf-8' );
		header( 'Content-Description: Media Library Report' );
		header( 'Content-Disposition: attachment; filename=' . $filename );
		header( 'Pragma: no-cache' );
		header( 'Expires: 0' );
	}

	/**
	 * Output an array of arrays as csv content.
	 *
	 * Assumes headers are already sent and that no other content is being sent.
	 *
	 * Each inner array must have the same number of fields and at least the first array
	 * must have keys that are used column headers.
	 *
	 * @param array $rows Array of arrays containing data to output.
	 */
	public function output_array_as_csv( $rows ) {
		$file = fopen( 'php://output', 'w' );

		fputcsv( $file, array_keys( reset( $rows ) ) );

		foreach ( $rows as $row ) {
			fputcsv( $file, $row );
		}
	}
}