is_writable

Tells whether the filename is writable (PHP 4, PHP 5)
bool is_writable ( string filename )

Example 659. is_writable() example

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<?php

$filename = 'test.txt';

if (is_writable($filename)) {

    echo 'The file is writable';

} else {

    echo 'The file is not writable';

}
?>

Related Examples ( Source code ) » is_writable

Examples ( Source code ) » Is the file writable

Examples ( Source code ) » Checking the Mode of a File

Code Examples / Notes » is_writable

claude dot paroz

Under Windows, it only returns the read-only attribute status, not the actual permissions (ACL). See http://bugs.php.net/bug.php?id=27609

nils kuebler

this one recursivly checks if a folder and all its contents are writeable <?php function is_removeable($dir) { $folder = opendir($dir); while($file = readdir( $folder )) if($file != '.' && $file != '..' && ( !is_writable( $dir."/".$file ) || ( is_dir( $dir."/".$file ) && !is_removeable( $dir."/".$file ) ) )) { closedir($dir); return false; } closedir($dir); return true; } ?>

legolas558 d0t users dot sf dot net

This is the latest version of is__writable() I could come up with. It can accept files or folders, but folders should end with a trailing slash! The function attempts to actually write a file, so it will correctly return true when a file/folder can be written to when the user has ACL write access to it. <?php function is__writable($path) { //will work in despite of Windows ACLs bug //NOTE: use a trailing slash for folders!!! //see http://bugs.php.net/bug.php?id=27609 //see http://bugs.php.net/bug.php?id=30931 if ($path{strlen($path)-1}=='/') // recursively return a temporary file path return is__writable($path.uniqid(mt_rand()).'.tmp'); else if (is_dir($path)) return is__writable($path.'/'.uniqid(mt_rand()).'.tmp'); // check tmp file for read/write capabilities $rm = file_exists($path); $f = @fopen($path, 'a'); if ($f===false) return false; fclose($f); if (!$rm) unlink($path); return true; } ?>

agrenier

This file_write() function will give $filename the write permission before writing $content to it. Note that many servers do not allow file permissions to be changed by the PHP user. <?php function file_write($filename, &$content) { if (!is_writable($filename)) { if (!chmod($filename, 0666)) { echo "Cannot change the mode of file ($filename)"; exit; }; } if (!$fp = @fopen($filename, "w")) { echo "Cannot open file ($filename)"; exit; } if (fwrite($fp, $content) === FALSE) { echo "Cannot write to file ($filename)"; exit; } if (!fclose($fp)) { echo "Cannot close file ($filename)"; exit; } } ?>

legolas558 dot sourceforge comma net

Since looks like the Windows ACLs bug "wont fix" (see http://bugs.php.net/bug.php?id=27609) I propose this alternative function: <?php function is__writable($path) { if ($path{strlen($path)-1}=='/') return is__writable($path.uniqid(mt_rand()).'.tmp'); if (file_exists($path)) { if (!($f = @fopen($path, 'r+'))) return false; fclose($f); return true; } if (!($f = @fopen($path, 'w'))) return false; fclose($f); unlink($path); return true; } ?> It should work both on *nix and Windows NOTE: you must use a trailing slash to identify a directory

f dot knodt

Same here with PHP 5.1.4. is_writable ignores my ACLs and also groups dont work sometimes.

jimmynighthawk

Regarding you might recognize your files on your web contructed by your PHP-scripts are grouped as NOBODY you can avoid this problem by setting up an FTP-Connection ("ftp_connect", "ftp_raw", etc.) and use methods like "ftp_fput" to create these [instead of giving out rights so you can use the usual "unsecure" way]. This will give the files created not the GROUP NOBODY - it will give out the GROUP your FTP-Connection via your FTP-Program uses, too. Furthermore you might want to hash the password for the FTP-Connection - then check out: http://dev.mysql.com/doc/mysql/en/Password_hashing.html

haccel

Ooooops, sorry! My mistake. is__writable should be: <?php function is__writable($path) { if ($path{strlen($path)-1}=='/') //Start function again with tmp file... return is__writable($path.uniqid(mt_rand()).'.tmp'); elseif (ereg('.tmp', $path)) { //Check tmp file for read/write capabilities if (!($f = @fopen($path, 'w+'))) return false; fclose($f); unlink($path); return true; } else //We have a path error. return 0; // Or return error - invalid path... } ?> The original could've deleted a folder if the path was invalid to start with (no trailing slash..) and the folder was writable to begin with...

darek

It appears that is_writable() does not check full permissions of a file to determine whether the current user can write to it. For example, with Apache running as user 'www', and a member of the group 'wheel', is_writable() returns false on a file like -rwxrwxr-x root wheel /etc/some.file

greg

In response to Darek: We have two servers: one running PHP 5.0.4 and Apache 1.3.33, the other running PHP 4.3.5 and Apache 1.3.27. The PHP 4 server exhibits the behavior you are describing, with is_writable() returning 'false' even though the www user is in the group that owns the file, but the PHP 5 server is returning 'true.'

wuhai

I was trying to create a new file using fwrite, and i had the following error. Any idea? Warning: fwrite(): supplied argument is not a valid stream resource in