regarding note from rehfeld dot us :
In my experience the best( and easiest ) way to find the extension of a file is :
<?php
// use this when you are sure it actually has an extension.
$extension = end(explode(".", $file_name));
?>
or
<?php
// this one will also check if it actually has an extension
$parts = explode(".", $file_name);
if (is_array($parts) && count($parts) > 1)
$extension = end($parts);
?>
is_file
(PHP 4, PHP 5)
is_file — Prüft, ob der Dateiname eine reguläre Datei ist
Beschreibung
$filename
)Prüft, ob der Dateiname eine reguläre Datei ist.
Parameter-Liste
-
filename -
Pfad zur Datei.
Rückgabewerte
Gibt TRUE zurück, wenn der Dateiname existiert und eine reguläre
Datei ist, sonst FALSE.
Hinweis: Weil PHPs Integer Typ vorzeichenbehaftet ist und viele Platformen 32bit Integer verweden, können einige Dateisystem-Funktionen für Dateien größer als 2GB unerwartete Ergebnisse liefern.
Beispiele
Beispiel #1 is_file()-Beispiel
<?php
var_dump(is_file('eine_datei.txt')) . "\n";
var_dump(is_file('/usr/bin/')) . "\n";
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
bool(true) bool(false)
Fehler/Exceptions
Im Fehlerfall wird eine E_WARNING ausgegeben.
Anmerkungen
Hinweis: Die Ergebnisse dieser Funktion werden gecached. Weitere Details erhalten Sie bei clearstatcache().
Seit PHP 5.0.0 kann diese Funktion mit einigen URL-Wrappern benutzt werden. Schauen Sie in der Liste unter Unterstützte Protokolle and Wrappers nach, welcher Wrapper die Funktionalität von stat() unterstützt.
is_file
27-Jun-2007 10:46
07-Feb-2007 12:22
Be careful with big files. I get a
Warning: is_file(): Stat failed for all.rar (errno=75 - Value too large for defined data type) in /.../test.php on line 3
and FALSE as result for a file of 3,5 GB.
18-Oct-2006 04:35
An easy way not to have to choose between hard-coding full paths and using relative paths is either via this line:
<?php
// in the bootstrap file
define('DIR_ROOT', dirname(__FILE__));
// in other files, prefix paths with the constant
require(DIR_ROOT . '/relative/to/bootstrap.php');
?>
or if you have to use a relative path:
<?php
require(dirname(__FILE__) . '/relative/to/this_file.php');
?>
This way all your paths will be absolute, yet you can move the application anywhere in the filesystem.
BTW, each successive call to dirname takes you one step up in the directory tree.
<?php
echo __FILE__;
// /www/site.com/public/index.php
echo dirname(__FILE__);
// /www/site.com/public
echo dirname(dirname(__FILE__));
// /www/site.com
?>
08-Aug-2006 07:39
In rlh's example, "$ext=explode('.',$document);" is only good if you consider that the filename only possesses a single dot (".") and that it is right before the extension. You should get the last dot's position with the strRPos() function instead.
Another note : some files might not even have an extension (i.e.: mostly under Linux/Unix).
12-Dec-2005 02:57
File operations such as is_file (also is_dir, opendir, readdir) work slower with Absolute paths - processing time is increase in 2-3 times.
Current rule is actual only for PHP5 (tested on 5.0.4, 5.1.1, Windows and Linux, 1st and 2nd Apache)
Try to use relative paths in these operators.
Example tested on my machine:
<?php
# note: in the both conditions file really exists!
# WIN XP, PHP4
# processing time: ~ 0.0003 sec.
if(is_file("images/10.jpg")) echo 'file exists';
# processing time: ~ 0.0002 sec. !!!
if(is_file("C:/server/htdocs/mysite/images/10.jpg")) echo 'file exists';
# WIN XP, PHP5
# processing time: ~ 0.0004 sec.
if(is_file("images/10.jpg")) echo 'file exists';
# processing time: ~ 0.0010 sec.
if(is_file("C:/server/htdocs/mysite/images/10.jpg")) echo 'file exists';
?>
14-Oct-2005 07:23
Maybe this is a newbie mistake, but note that paths are relative to the filesystem and the location of the script. This means that MS IIS virtual directories are not available by relative path - use an absolute.
This threw me because virtual directories ARE available for URLs, at least on IIS.
31-Aug-2005 03:45
be careful, is_file() fails on files larger than your integer storage (2^32 for most).
Warning: is_file(): Stat failed for bigfile (errno=75 - Value too large for defined data type)
11-Aug-2005 05:11
is_file returns false if you don't have the permissions for the file or the directory (eg.: you are web34 and the directory belongs to root)!
### Symbolic links are resolved ###
If you pass a symlink (unix symbolic link) as parameter, is_file will resolve the symlink and will give information about the refered file. For example:
touch file
ln -s file link
echo '<? if (is_file("link")) echo "y\n"; ?>' | php -q
will print "y".
is_dir resolves symlinks too.
25-Oct-2004 08:06
I tend to use alot of includes, and I found that the is_file is based on the script executed, not ran.
if you request /foo.php and foo.php looks like this:
<?php
include('foobar/bar.php');
?>
and bar.php looks like this:
<?php
echo (is_file('foo/bar.txt'));
?>
Then PHP (on win32, php 5.x) would look for /foo/bar.txt and not /foobar/foo/bar.txt.
you would have to rewrite the is_file statement for that, or change working directory.
Noting this since I sat with the problem for some time,
cheers, Toxik.
04-Sep-2004 12:04
regarding rlh at d8acom dot com method,
It is incorrect. Well, it works but you are not guaranteed the file extension using that method.
for example : filename.inc.php
your method will tell you the ext is "inc", but it is in fact "php"
heres a way that will work properly.
<?php
$dh = opendir($dir);
while (false !== ($document = readdir($dh))) {
$pos = strrpos($document, '.');
if (false !== $pos && strlen($document) > $pos + 1) {
$ext = substr($document, $pos + 1);
}
}
?>
12-Feb-2003 02:17
I do a lot of file parsing and have found the following technique extremely useful:
while (false !== ($document = readdir($my_dir)))
{
$ext=explode('.',$document);
if($document != '.' && $document != '..' && $ext[1])
{
'Do something to file...'
}
}
It gets around the fact that, when working on website pages, the html files are read as directories when downloaded. It also allows you to extend the usefulness of the above method by adding the ability to determine file types e.g.
if($document != '.' && $document != '..' && $ext[1]=='htm')
or
if($document != '.' && $document != '..' && $ext[1]=='doc')
27-Mar-2002 08:34
if you're running apache as a service on a win32 machine, an you try to determinate if a file on an other pc in your network exists - ex.: is_file('//servername/share/dir1/dir2/file.txt') - you may return false when you're running the service as LocalSystem. To avoid this, you have to start the Apache-Service as a 'registered' domain user.
14-Dec-2001 05:20
In PHP 4.1.0 under win32, this seems to print out a warning message if the file does not exist (using error_reporting = E_ALL & ~E_NOTICE).
12-Mar-2000 03:56
It seems that is_file doesn't return true for a file that is 0 bytes. Perhaps it is something with the file system. I am using IIS 3.0 on an NT4 box. I worked around it using !is_dir($filename) but that seems a clunky way to do it.