is_uploaded_file
To Darek and F Dot: About group permissions, there is this note in the php.ini file:
; By default, Safe Mode does a UID compare check when
; opening files. If you want to relax this to a GID compare,
; then turn on safe_mode_gid.
safe_mode_gid = Off
is_writable
(PHP 4, PHP 5)
is_writable — Tells whether the filename is writable
Description
bool is_writable
( string
$filename
)
Returns TRUE if the filename exists and is
writable. The filename argument may be a directory name allowing you
to check if a directory is writable.
Keep in mind that PHP may be accessing the file as the user id that the web server runs as (often 'nobody'). Safe mode limitations are not taken into account.
Parameters
-
filename -
The filename being checked.
Return Values
Returns TRUE if the filename exists and is
writable.
Examples
Example #1 is_writable() example
<?php
$filename = 'test.txt';
if (is_writable($filename)) {
echo 'The file is writable';
} else {
echo 'The file is not writable';
}
?>
Errors/Exceptions
Upon failure, an E_WARNING is emitted.
Notes
Note: The results of this function are cached. See clearstatcache() for more details.
Tip
As of PHP 5.0.0, this function can also be used with some URL wrappers. Refer to Supported Protocols and Wrappers to determine which wrappers support stat() family of functionality.
See Also
- is_readable() - Tells whether a file exists and is readable
- file_exists() - Checks whether a file or directory exists
- fwrite() - Binary-safe file write
add a note
User Contributed Notes
is_writable - [13 notes]
starrychloe at yahoo dot com ¶
5 years ago
agrenier at assertex dot com ¶
9 years ago
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;
}
}
?>
darek at fauxaddress dot com ¶
7 years ago
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
JimmyNighthawk ¶
7 years ago
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
gr ¶
2 years ago
The results of this function seems to be not cached :
Tested on linux and windows
<?php
chmod($s_pathFichier, 0400);
echo'<pre>';var_dump(is_writable($s_pathFichier));echo'</pre>';
chmod($s_pathFichier, 04600);
echo'<pre>';var_dump(is_writable($s_pathFichier));echo'</pre>';
exit;
?>
wuhai ¶
5 years ago
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
legolas558 d0t users dot sf dot net ¶
6 years ago
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;
}
?>
legolas558 dot sourceforge comma net ¶
6 years ago
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
greg at gregwhitescarver dotcalm ¶
7 years ago
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.'
claude dot paroz at ne dot ch ¶
9 years ago
Under Windows, it only returns the read-only attribute status, not the actual permissions (ACL).
See http://bugs.php.net/bug.php?id=27609
haccel at email dot com ¶
6 years ago
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($path);
return true;
}
else //We have a path error.
return 0; // Or return error - invalid path...
}
?>
The original could've deleted a folder if the path was invalid to start with (no trailing slash..) and the folder was writable to begin with...
haccel at email dot com ¶
6 years ago
Be careful of legolas558 dot sourceforge comma net's example, try this instead:
<?php
function is__writable($path)
{
if ($path{strlen($path)-1}=='/')
return is__writable($path.uniqid(mt_rand()).'.tmp');
elseif (file_exists($path) && ereg('.tmp', $path))
{
if (!($f = @fopen($path, 'w+')))
return false;
fclose($f);
unlink($path);
return true;
}
else
return 0; // Or return error - invalid path...
}
?>
Nils Kuebler ¶
7 years ago
this one recursivly checks if a folder and all its contents are writeable
<?php
function is_removeable($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;
}
?>