Be warned, that is_writable returns false for non-existent files, although they can be written to the queried path.
(PHP 4, PHP 5, PHP 7, PHP 8)
is_writable — Indica si un archivo existe y es escribible
Devuelve true si filename existe y es
escribible. El argumento nombre_archivo puede ser el nombre de un directorio, permitiendo así
comprobar si el directorio es escribible.
Tenga en cuenta que PHP puede estar accediendo al archivo bajo el id de ususario por el que se está ejecutando el servidor web (a menudo 'nobody'). Las limitaciones del modo seguro no se toman en cuenta.
filenameEl nombre de archivo que va a ser comprobado.
Devuelve true si el parámetro filename existe y es
escribible.
Ejemplo #1 Ejemplo de is_writable()
<?php
$nombre_archivo = 'prueba.txt';
if (is_writable($nombre_archivo)) {
echo 'El archivo es escribible';
} else {
echo 'El archivo no es escribible';
}
?>
En caso de fallo, se emite un E_WARNING.
Nota: Los resultados de esta función son guardados en caché. Para más información ver clearstatcache().
Desde PHP 5.0.0, esta función también puede usarse con algunos URL wrappers. Consultar Protocolos y Envolturas soportados para deter4minar qué envolturas soportan la familia de funcionalidad de stat().
Be warned, that is_writable returns false for non-existent files, although they can be written to the queried path.In Linux, you might encountering an issue which is a file is not writable even tho it has 644 permission! The problem is with SELinux, just disable it or add rules to allow it.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 = OffCheck director is writable recursively. to return true, all of directory contents must be writable
<?php
function is_writable_r($dir) {
if (is_dir($dir)) {
if(is_writable($dir)){
$objects = scandir($dir);
foreach ($objects as $object) {
if ($object != "." && $object != "..") {
if (!is_writable_r($dir."/".$object)) return false;
else continue;
}
}
return true;
}else{
return false;
}
}else if(file_exists($dir)){
return (is_writable($dir));
}
}
?>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.fileRegarding 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.htmlThis 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;
}
}
?>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;
?>This function returns always false on windows, when you check an network drive.
See PHP Bug https://bugs.php.net/bug.php?id=68926
See https://stackoverflow.com/q/54904676