file_exists

(PHP 3, PHP 4, PHP 5)

file_exists -- 检查文件或目录是否存在

说明

bool file_exists ( string filename )

如果由 filename 指定的文件或目录存在则返回 TRUE,否则返回 FALSE

在 Windows 中要用 //computername/share/filename 或者 \\computername\share\filename 来检查网络中的共享文件。

例子 1. 测试一个文件是否存在

<?php
$filename
= '/path/to/foo.txt';

if (
file_exists($filename)) {
    echo
"The file $filename exists";
} else {
    echo
"The file $filename does not exist";
}
?>

注: 本函数的结果会被缓存。更多信息参见 clearstatcache()

提示: PHP 5.0.0 起本函数也可被某些 URL wrapper 使用。参考附录 L 来看哪些 wrapper 支持 stat() 系列函数的功能。

警告

如果因为安全模式的限制而导致不能访问文件的话,该函数会返回 FALSE。然而,如果文件在 safe_mode_include_dir 所指定的目录内的话,仍然可以使用 include 来包含。

参见 is_readable()is_writable()is_file()file()


add a note add a note User Contributed Notes
sirarthur at sirarthur dot info
11-May-2006 03:04
The following code will rename an uploaded image to a MD5 hash with a rand number added of its name and check wheter a file with same hash already exists or not:

<?php
$file
= $HTTP_POST_FILES['file'];
$image=new Image($imgfld,$file);
if(
$image->FType != null){
if (
$image->FType=="image/gif") {
$ext = ".gif";
}else{
$ext = ".jpg";
}
 
$nfile = md5($image->Name . rand());
while(
file_exists($imgfld . $nfile . $ext) == true){
 
$nfile = md5($image->Name . rand());
}
 
$image->ResizedWidth = $imggrx;
 
$image->ResizedHeight = $imggry;
 
$image->Resample($nfile);
?>

It uses an image class found at phpclasses.org
pilotdoofy at gmail dot com
23-Apr-2006 04:35
I wrote a very simple function that allows you to search a folder for a file name with a regular expression. It can handle both PREG and EREG regexps and can accept different case sensitivities for EREG regexps.

function regExpFile($regExp, $dir, $regType='P', $case='') {
# Two parameters accepted by $regType are E for ereg* functions
# and P for preg* functions
$func = ( $regType == 'P' ) ? 'preg_match' : 'ereg' . $case;

# Note, technically anything other than P will use ereg* functions;
# however, you can specify whether to use ereg or eregi by
# declaring $case as "i" to use eregi rather than ereg

$open = opendir($dir);
while( ($file = readdir($open)) !== false ) {
if ( $func($regExp, $file) ) {
return true;
}
} // End while
return false;
} // End function

Basically if you supply anything but "P" for $regType it will assume you're using EREG regexps. The case should only be blank or "i".
hiro at arkusa dot com
08-Feb-2006 05:23
As of php 5.0.4, many (if not all) php file manipulation functions fail if a file's size is no smaller than 2GB (i.e. 2^31) on the x86 platforms. Even file_exists() fails (always returns FALSE). This puzzled me when I was writing a video file manipulation application.

A simple alternative is like:

function file_exists_2gb($filename) {
   system("test -f $filename", $rval);
   return ($rval == 0);
}
08-Jan-2006 05:08
I wrote this little handy function to check if an image exists in a directory, and if so, return a filename which doesnt exists e.g. if you try 'flower.jpg' and it exists, then it tries 'flower[1].jpg' and if that one exists it tries 'flower[2].jpg' and so on. It works fine at my place. Ofcourse you can use it also for other filetypes than images.

<?php
function imageExists($image,$dir) {

  
$i=1; $probeer=$image;

   while(
file_exists($dir.$probeer)) {
      
$punt=strrpos($image,".");
       if(
substr($image,($punt-3),1)!==("[") && substr($image,($punt-1),1)!==("]")) {
          
$probeer=substr($image,0,$punt)."[".$i."]".
          
substr($image,($punt),strlen($image)-$punt);
       } else {
          
$probeer=substr($image,0,($punt-3))."[".$i."]".
          
substr($image,($punt),strlen($image)-$punt);
       }
      
$i++;
   }
   return
$probeer;
}
?>
Fabrizio (staff at bibivu dot com)
22-Dec-2005 10:11
here a function to check if a certain URL exist:
<?php
  
function url_exists($url) {
      
$a_url = parse_url($url);
       if (!isset(
$a_url['port'])) $a_url['port'] = 80;
      
$errno = 0;
      
$errstr = '';
      
$timeout = 30;
       if(isset(
$a_url['host']) && $a_url['host']!=gethostbyname($a_url['host'])){
          
$fid = fsockopen($a_url['host'], $a_url['port'], $errno, $errstr, $timeout);
           if (!
$fid) return false;
          
$page = isset($a_url['path'])  ?$a_url['path']:'';
          
$page .= isset($a_url['query'])?'?'.$a_url['query']:'';
          
fputs($fid, 'HEAD '.$page.' HTTP/1.0'."\r\n".'Host: '.$a_url['host']."\r\n\r\n");
          
$head = fread($fid, 4096);
          
fclose($fid);
           return
preg_match('#^HTTP/.*\s+[200|302]+\s#i', $head);
       } else {
           return
false;
       }
   }
?>

in my CMS, I am using it with those lines:
<?php
      
if(!isset($this->f_exist[$image]['exist']))
           if(
strtolower(substr($fimage,0,4)) == 'http' || strtolower(substr($fimage,0,4)) == 'www.'){
               if(
strtolower(substr($image,0,4)) == 'www.'){
                  
$fimage = 'http://'.$fimage;
                  
$image = 'http://'.$image;
               }
              
$this->f_exist[$image]['exist'] = $this->url_exists($fimage); //for now
          
} else {
              
$this->f_exist[$image]['exist'] = ($fimage!='' && file_exists($fimage) && is_file($fimage) && is_readable($fimage) && filesize($fimage)>0);
           }
       }
?>
flobee
13-Dec-2005 08:24
file_exists overwrites the last access (atime) !
try:
if (@fclose(@fopen( $file, "r"))) {
                     // true;
                 } else {
                     // false;
                 }
to check if important for you
ihoss dot com at gmail dot com
19-Oct-2005 10:37
The following script checks if there is a file with the same name and adds _n to the end of the file name, where n increases. if img.jpg is on the server, it tries with img_0.jpg, checks if it is on the server and tries with img_1.jpg.
<?php
  $img
= "images/".$_FILES['bilde']['name'];
 
$t=0;
  while(
file_exists($img)){
  
$img = "images/".$_FILES['bilde']['name'];
  
$img=substr($img,0,strpos($img,"."))."_$t".strstr($img,".");
  
$t++;
  }
 
move_uploaded_file($_FILES['bilde']['tmp_name'], $img);
?>
phenbach at phenbach dot com
20-Sep-2005 06:37
I recently had an issue with PLESK and copying file to other directories with the move_uploaded file function.

This would work on every linux server except plesk servers. I could figure it out and have yet to find out.  I had to create a work a round and decided to use the exec() function.

As noted above the file_exist() function must need to wait for some time and I found the looking function a waste of resouces and didn't work for me anyway. So this is what I came up with.

function cp($source,$destination){

$cmd="cp -u ".$source ." ".$destination; //create the command string to copy with the update option
exec($cmd); //exec command
$cmd_test="ls -la ".$destination; //list file
exec($cmd_test,$out);
//If the file is present it $out[0] key will contain the file info.
//if it is not present it will be null
if (isset($out[0])){
     return true;
}else{
     return false;
}
   }
davidc at php dot net
14-Sep-2005 04:05
Also while using the file_exists file, please make sure you do not start using stuff like,

<?php

if(file_exists($_GET['file'] . '.php')) {
   include(
$_GET['file'] . '.php';
}

?>

you could use something like this..

<?php
   $inrep
= "./";
  
$extfichier = ".php";
  
$page = $inrep.basename(strval($_REQUEST["page"]),$extfichier).extfichier;
   if(
file_exist($page)) {
       include(
$page);
   }
?>

or even hardcode it.

  So since pretty much all commercial server(s) have url_fopen on.. you can imagine that file_exists($_GET['file']. '.php')
is rather .. unsecure :)

-David Coallier
tma at 2p dot cz
24-Aug-2005 04:47
If checking for a file newly created by an external program in Windows then file_exists() does not recognize it immediately.  Iy seems that a short timeout may be required.

<?
   $file
= 'file.tmp';
   if (
$h = popen("start \"bla\" touch $file", "r")) {
    
pclose($h);
  
// now I would like know if a file was created
   // note: usleep not supported
    
$start = gettimeofday(); 
     while (!
file_exists(trim($file, " '\""))) {
      
$stop = gettimeofday();
       if (
1000000 * ($stop['sec'] - $start['sec']) + $stop['usec'] - $start['usec'] > 500000) break;  // wait a moment
    
}

     if (
file_exists($file))  // now should be reliable
?>
09-Aug-2005 10:20
That is true feshi. But, if you have your server configured correctly, those access logs will only be accessible by an admin or the root account. The webuser account that runs the php script will be unable to start reading from that file. That's the easiest fix.
feshi
04-Aug-2005 06:34
this code looks inocent

<?php
$filename
=$_REQUEST["var"];
$filename .= ".data";
file_exist($filename){
  include(
$filename);
}
?>

but if you pass something like script.php?var=test%00asbs
it should really can do bad things like including accesslog files if you replace "test" with something like "../logs/accesslog"
joe dot knall at gmx dot net
16-Mar-2005 07:59
concerning file_exists and safe_mode:
if safe_mode=ON and $file (in safe_mode_include_dir) is not owned by the user who executes file_exists($file), file_exists returns FALSE but still $file can be included;
I could handle this by setting safe_mode_gid=On and appropriate group-ownership
07-Mar-2005 06:00
Nathaniel, you should read the manual carefuly next time prior to posting anything here, as all you indicated is the fact you missed the idea of the include_path. To remind - include_path is for some functions only, mainly intended for include and require to simpify include/require operations (kinda way the #include works). It is NOT for any filesystem function, which would be damn annoying than helpful, which is quite understandable and obvious.
andrewNOSPAMPLEASE at abcd dot NOSPAMERSca
11-Feb-2005 09:29
file_exists will have trouble finding your file if the file permissions are not read enabled for 'other' when not owned by your php user. I thought I was having trouble with a directory name having a space in it (/users/andrew/Pictures/iPhoto Library/AlbumData.xml) but the reality was that there weren't read permissions on Pictures, iPhoto Library or AlbumData.xml. Once I fixed that, file_exists worked.
Nathaniel
09-Feb-2005 01:08
I spent the last two hours wondering what was wrong with my if statement: file_exists($file) was returning false, however I could call include($file) with no problem.

It turns out that I didn't realize that the php include_path value I had set in the .htaccess file didn't carry over to file_exists, is_file, etc.

Thus:

<?PHP
// .htaccess php_value include_path '/home/user/public_html/';

// includes lies in /home/user/public_html/includes/

//doesn't work, file_exists returns false
if ( file_exists('includes/config.php') )
{
     include(
'includes/config.php');
}

//does work, file_exists returns true
if ( file_exists('/home/user/public_html/includes/config.php') )
{
   include(
'includes/config.php');
}
?>

Just goes to show that "shortcuts for simplicity" like setting the include_path in .htaccess can just cause more grief in the long run.
ceo at l-i-e dot com
03-Dec-2004 07:44
Prior to 4.3.2, and 4.3.3 with open_basedir, this function generated an error/warning message when the file/directory in question did not exist.
aidan at php dot net
11-Apr-2004 12:46
If you'd like to check if a file exists anywhere your include path, have a look at this function:

http://aidan.dotgeek.org/lib/?file=function.file_exists_incpath.php
alex at raynor nospam dot ru
05-Apr-2004 11:16
If you use open_basedir in php.ini and use file_exists for file outside open_basedir path, you will not be warned at log and file_exists returns false even if file really exists.
12-Feb-2004 10:32
On nix systems file_exists will report a link that doesn't point to a valid file as non-existant, ie: the link itself exists but the file it points to does not.  Using is_link will report true whether the link points to a valid file or not.