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

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$filestring

Full path and filename of ZIP archive.

$tostring

Full path on the filesystem to extract archive to.

Return value

true|WP_Error

True on success, WP_Error on failure.

Performance profile

How much work a call to unzip_file() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

12–75

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 88.

Plugin surface

1 hook

Third-party callbacks on 'unzip_file_use_ziparchive' run inside this call, and their cost is not bounded by anything here.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly
• regexregular expression over the whole inputpreg_split()called directly

Further down the call graph this can also reach option, cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 19 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost unzip_file() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while unzip_file() runs, in this order:

1. 1
   apply_filters( unzip_file_use_ziparchive )filterline 1655 (+41 into the body)

   Filters whether to use ZipArchive to unzip archives.

Uses · 9

• __()Retrieves the translation of $text.
• wp_raise_memory_limit()Attempts to raise the PHP memory limit for memory intensive processes.
• trailingslashit()Appends a trailing slash.
• untrailingslashit()Removes trailing forward slashes and backslashes if they exist.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• _unzip_file_ziparchive()Attempts to unzip an archive using the ZipArchive class.
• is_wp_error()Checks whether the given variable is a WordPress Error.
• _unzip_file_pclzip()Attempts to unzip an archive using the PclZip library.
• WP_Error::__construct()Initializes the error.

Used by · 1

• WP_Upgrader::unpack_package()Unpacks a compressed package file.

Source code

View on Trac ↗View on GitHub ↗

1614function unzip_file( $file, $to ) {1615	global $wp_filesystem;1616 1617	if ( ! $wp_filesystem || ! is_object( $wp_filesystem ) ) {1618		return new WP_Error( 'fs_unavailable', __( 'Could not access filesystem.' ) );1619	}1620 1621	// Unzip can use a lot of memory, but not this much hopefully.1622	wp_raise_memory_limit( 'admin' );1623 1624	$needed_dirs = array();1625	$to          = trailingslashit( $to );1626 1627	// Determine any parent directories needed (of the upgrade directory).1628	if ( ! $wp_filesystem->is_dir( $to ) ) { // Only do parents if no children exist.1629		$path = preg_split( '![/\\\]!', untrailingslashit( $to ) );1630		for ( $i = count( $path ); $i >= 0; $i-- ) {1631			if ( empty( $path[ $i ] ) ) {1632				continue;1633			}1634 1635			$dir = implode( '/', array_slice( $path, 0, $i + 1 ) );1636			if ( preg_match( '!^[a-z]:$!i', $dir ) ) { // Skip it if it looks like a Windows Drive letter.1637				continue;1638			}1639 1640			if ( ! $wp_filesystem->is_dir( $dir ) ) {1641				$needed_dirs[] = $dir;1642			} else {1643				break; // A folder exists, therefore we don't need to check the levels below this.1644			}1645		}1646	}1647 1648	/**1649	 * Filters whether to use ZipArchive to unzip archives.1650	 *1651	 * @since 3.0.01652	 *1653	 * @param bool $ziparchive Whether to use ZipArchive. Default true.1654	 */1655	if ( class_exists( 'ZipArchive', false ) && apply_filters( 'unzip_file_use_ziparchive', true ) ) {1656		$result = _unzip_file_ziparchive( $file, $to, $needed_dirs );1657		if ( true === $result ) {1658			return $result;1659		} elseif ( is_wp_error( $result ) ) {1660			if ( 'incompatible_archive' !== $result->get_error_code() ) {1661				return $result;1662			}1663		}1664	}1665	// Fall through to PclZip if ZipArchive is not available, or encountered an error opening the file.1666	return _unzip_file_pclzip( $file, $to, $needed_dirs );1667}

Changelog

Introduced in 2.5.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-admin/includes/file.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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