PHP Phrasebook

It is rather unusual to use PHP for accessing directory and file informationat least as long as the vast majority of PHP scripts run via HTTP in a web server and not using the command line interface (CLI) or PHP.

However, PHP offers a variety of helper functions that provide information about a file. Most of them are just calling the relevant operating system functions.

Reading Information About Files (fileinfos.php)

<?php $filename = __FILE__; $data = array( 'fileatime' => fileatime($filename), 'filegroup' => filegroup($filename), 'filemtime' => filemtime($filename), 'fileowner' => fileowner($filename), 'filesize' => filesize($filename), 'is_dir' => var_export(is_dir($filename), true), 'is_executable' => var_export(is_executable($filename), true), 'is_file' => var_export(is_file($filename), true), 'is_link' => var_export(is_link($filename), true), 'is_readable' => var_export(is_readable ($filename), true), 'is_uploaded_file' => var_export (is_uploaded_file($filename), true), 'is_writable' => var_export (is_writable($filename), true) ); echo '<table>'; foreach ($data as $function => $result) { echo "<tr><td>$function</td><td>$result</td></tr>"; } echo '</table>'; ?>

The following list shows the most relevant helper functions in this regard:

• fileatime($filename) Last access to the file

• filegroup($filename) Group that owns the file

• filemtime($filename) Last change to the file

• fileowner($filename) File owner

• filesize($filename) Size of the file

Another set of helper functions also takes a filename, so the files do not have to be opened before you use these functions:

• is_dir($path) Whether the path is a directory

• is_executable($filename) Whether the filename is an executable

• is_file($path) Whether the path is a (regular) file

• is_link($filename) Whether the filename is a symbolic link

• is_readable($filename) Whether the file is readable

• is_uploaded_file($path) Whether the path is a file uploaded via HTTP (see Chapter 5, "Remembering Users (Cookies and Sessions)")

• is_writable($filename) Whether the file is writable

Figure 6.5 contains the result of the code at the beginning of this phrase.