unzip_file( string $file, string $to ): true|WP_Error

Unzips a specified ZIP file to a location on the filesystem via the WordPress Filesystem Abstraction.

Description

Assumes that WP_Filesystem() has already been called and set up. Does not extract a root-level __MACOSX directory, if present.

Attempts to increase the PHP memory limit to 256M before uncompressing. However, the most memory required shouldn’t be much larger than the archive itself.

Parameters

$filestringrequired
Full path and filename of ZIP archive.
$tostringrequired
Full path on the filesystem to extract archive to.

Return

true|WP_Error True on success, WP_Error on failure.

Source

function unzip_file( $file, $to ) {
	global $wp_filesystem;

	if ( ! $wp_filesystem || ! is_object( $wp_filesystem ) ) {
		return new WP_Error( 'fs_unavailable', __( 'Could not access filesystem.' ) );
	}

	// Unzip can use a lot of memory, but not this much hopefully.
	wp_raise_memory_limit( 'admin' );

	$needed_dirs = array();
	$to          = trailingslashit( $to );

	// Determine any parent directories needed (of the upgrade directory).
	if ( ! $wp_filesystem->is_dir( $to ) ) { // Only do parents if no children exist.
		$path = preg_split( '![/\\\]!', untrailingslashit( $to ) );
		for ( $i = count( $path ); $i >= 0; $i-- ) {
			if ( empty( $path[ $i ] ) ) {
				continue;
			}

			$dir = implode( '/', array_slice( $path, 0, $i + 1 ) );
			if ( preg_match( '!^[a-z]:$!i', $dir ) ) { // Skip it if it looks like a Windows Drive letter.
				continue;
			}

			if ( ! $wp_filesystem->is_dir( $dir ) ) {
				$needed_dirs[] = $dir;
			} else {
				break; // A folder exists, therefore we don't need to check the levels below this.
			}
		}
	}

	/**
	 * Filters whether to use ZipArchive to unzip archives.
	 *
	 * @since 3.0.0
	 *
	 * @param bool $ziparchive Whether to use ZipArchive. Default true.
	 */
	if ( class_exists( 'ZipArchive', false ) && apply_filters( 'unzip_file_use_ziparchive', true ) ) {
		$result = _unzip_file_ziparchive( $file, $to, $needed_dirs );
		if ( true === $result ) {
			return $result;
		} elseif ( is_wp_error( $result ) ) {
			if ( 'incompatible_archive' !== $result->get_error_code() ) {
				return $result;
			}
		}
	}
	// Fall through to PclZip if ZipArchive is not available, or encountered an error opening the file.
	return _unzip_file_pclzip( $file, $to, $needed_dirs );
}

Hooks

apply_filters( ‘unzip_file_use_ziparchive’, bool $ziparchive )

Filters whether to use ZipArchive to unzip archives.

Changelog

VersionDescription
2.5.0Introduced.

User Contributed Notes

  1. Skip to note 2 content

    Example

    Basic example showing how to unzip the contents of a .zip file, that resides in the WordPress upload directory, to the same destination.

    <?php
    WP_Filesystem();
    $destination = wp_upload_dir();
    $destination_path = $destination['path'];
    $unzipfile = unzip_file( $destination_path.'/filename.zip', $destination_path);
       
       if ( $unzipfile ) {
          echo 'Successfully unzipped the file!';       
       } else {
          echo 'There was an error unzipping the file.';       
       }
    ?>

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