Hướng dẫn file_exists php

(PHP 4, PHP 5, PHP 7, PHP 8)

file_exists — Checks whether a file or directory exists

Description

file_exists(string $filename): bool

Parameters

Path to the file or directory.

On windows, use //computername/share/filename or \\computername\share\filename to check files on network shares.

Return Values

Returns true if the file or directory specified by filename exists; false otherwise.

Note:

This function will return false for symlinks pointing to non-existing files.

Note:

The check is done using the real UID/GID instead of the effective one.

Note: Because PHP's integer type is signed and many platforms use 32bit integers, some filesystem functions may return unexpected results for files which are larger than 2GB.

Errors/Exceptions

Upon failure, an E_WARNING is emitted.

Examples

Example #1 Testing whether a file exists

$filename = '/path/to/foo.txt';

if (

Notes

Note: The results of this function are cached. See clearstatcache() for more details.

See Also

• is_readable() - Tells whether a file exists and is readable
• is_writable() - Tells whether the filename is writable
• is_file() - Tells whether the filename is a regular file
• file() - Reads entire file into an array
• SplFileInfo

maurice at idify dot nl ¶

14 years ago

Note: The results of this function are cached. See clearstatcache() for more details.

That's a pretty big note. Don't forget this one, since it can make your file_exists() behave unexpectedly - probably at production time ;)

welkom at remconijhuis dot nl ¶

8 years ago

I needed to measure performance for a project, so I did a simple test with one million file_exists() and is_file() checks. In one scenario, only seven of the files existed. In the second, all files existed. is_file() needed 3.0 for scenario one and 3.3 seconds for scenario two.  file_exists() needed 2.8 and 2.9 seconds, respectively. The absolute numbers are off course system-dependant, but it clearly indicates that file_exists() is faster.

ziptwipi at goioia dot com ¶

6 years ago

Note that realpath() will return false if the file doesn't exist. So if you're going to absolutize the path and resolve symlinks anyway, you can just check the return value from realpath() instead of calling file_exists() first

vernon at kesnerdesigns dot net ¶

15 years ago

In response to seejohnrun's version to check if a URL exists. Even if the file doesn't exist you're still going to get 404 headers.  You can still use get_headers if you don't have the option of using CURL..

$file = 'http://www.domain.com/somefile.jpg';
$file_headers = @get_headers($file);
if($file_headers[0] == 'HTTP/1.1 404 Not Found') {
    $exists = false;
}
else {
    $exists = true;
}

bvazquez at siscomx dot com ¶

15 years ago

If you are trying to access a Windows Network Share you have to configure your WebServer with enough permissions for example:

$file = fopen("\\siscomx17\c\websapp.log",'r');

You will get an error telling you that the pathname doesnt exist this will be because Apache or IIS run as LocalSystem so you will have to enter to Services and configure Apache on "Open a session as" Create a new user that has enough permissions and also be sure that target share has the proper permissions.

Hope this save some hours of research to anyone.

jag ¶

3 years ago

file_exists() does NOT search the php include_path for your file, so don't use it before trying to include or require.

use

    @$result = include $filename;

Yes, include does return false when the file can't be found, but it does also generate a warning. That's why you need the @. Don't try to get around the warning issue by using file_exists(). That will leave you scratching your head until you figure out or stumble across the fact that file_exists() DOESN'T SEARCH THE PHP INCLUDE_PATH.

vcoletti at tiscali dot it ¶

5 years ago

With PHP 7.0 on Ubuntu 17.04 and with the option allow_url_fopen=On, file_exists() returns always false when trying to check a remote file via HTTP.

So
        $url="http://www.somewhere.org/index.htm";
        if (file_exists($url)) echo "Wow!\n";
        else echo "missing\n";

returns always "missing", even for an existing URL.

I found that in the same situation the file() function can read the remote file, so I changed my routine in

        $url="http://www.somewhere.org/index.htm";
        if (false!==file($url)) echo "Wow!\n";
        else echo "missing\n";

                This is clearly a bit slower, especially if the remote file is big, but it solves this little problem.

ktcb123 at hotmail dot com ¶

14 years ago

For some reason, none of the url_exists() functions posted here worked for me, so here is my own tweaked version of it.

    function url_exists($url){
        $url = str_replace("http://", "", $url);
        if (strstr($url, "/")) {
            $url = explode("/", $url, 2);
            $url[1] = "/".$url[1];
        } else {
            $url = array($url, "/");
        }$fh = fsockopen($url[0], 80);
        if ($fh) {
            fputs($fh,"GET ".$url[1]." HTTP/1.1\nHost:".$url[0]."\n\n");
            if (fread($fh, 22) == "HTTP/1.1 404 Not Found") { return FALSE; }
            else { return TRUE;    }

        } else { return

Fabrizio (staff at bibivu dot com) ¶

16 years ago

here a function to check if a certain URL exist:
    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:
        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);
            }
        }
?>

earle dot west at transactionalweb dot com ¶

15 years ago

If the file being tested by file_exists() is a file on a symbolically-linked directory structure, the results depend on the permissions of the directory tree node underneath the linked tree.   PHP under a web server (i.e. apache) will respect permissions of the file system underneath the symbolic link, contrasting with PHP as a shell script which respects permissions of the directories that are linked (i.e. on top, and visible).  

This results in files that appear to NOT exist on a symbolic link, even though they are very much in existance and indeed are readable by the web server.

stuart ¶

14 years ago

When using file_exists, seems you cannot do:

foreach ($possibles as $poss)
{
    if ( file_exists(SITE_RANGE_IMAGE_PATH .$this->range_id .'/ '.$poss .'.jpg') )
    {
        // exists
    }
    else
    {
        // not found
    }
}
?>

so you must do:

foreach ($possibles as $poss)
{
    $img = SITE_RANGE_IMAGE_PATH .$this->range_id .'/ '.$poss .'.jpg'
    if ( file_exists($img) )
    {
        // exists
    }
    else
    {
        // not found
    }
}
?>

Then things will work fine.

This is at least the case on this Windows system running php 5.2.5 and apache 2.2.3

Not sure if it is down to the concatenation or the fact theres a constant in there, i'm about to run away and test just that...

Anonymous ¶

16 years ago

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.

function imageExists($image,$dir) {$i=1; $probeer=$image;

    while(

guillermogomezruiz at gmail dot com ¶

15 years ago

I was having problems with the file_exists when using urls, so I made this function:

function file_exists_2($filePath)
{
    return ($ch = curl_init($filePath)) ? @curl_close($ch) || true : false;
}
?>

Cheers!

spark at limao dot com dot br ¶

11 years ago

this code here is in case you want to check if a file exists in another server:

function fileExists($path){
    return (@fopen($path,"r")==true);
}
?>

unfortunately the file_exists can't reach remote servers, so I used the fopen function.

dan at sudonames dot com ¶

14 years ago

Here is a simpler version of url_exists:

function url_exists($url) {
    $hdrs = @get_headers($url);
    return is_array($hdrs) ? preg_match('/^HTTP\\/\\d+\\.\\d+\\s+2\\d\\d\\s+.*$/',$hdrs[0]) : false;
}
?>

jaz-t at hotmail dot com ¶

14 years ago

Note on openspecies entry (excellent btw, thanks!).

If your server cannot resolve its own DNS, use the following:
$f = preg_replace('/www\.yourserver\.(net|com)/', getenv('SERVER_ADDR'), $f);

Just before the $h = @get_headers($f); line.

Replace the extensions (net|com|...) in the regexp expression as appropriate.

EXAMPLE:
File you are checking for: http://www.youserver.net/myfile.gif
Server IP: 10.0.0.125

The preg_replace will effectively 'resolve' the address for you by assigning $f as follows:
http://10.0.0.125/myfile.gif

Steve GS ¶

5 months ago

Wordpress always prepends the full URL to any file it stores in its database so, as noted elsewhere, file_exists() can't find the file since it uses the 'document root', not the URL.  An easy way out of this is to use:

file_exists (str_replace (home_url(), $_SERVER['DOCUMENT_ROOT'], $file) )

to check if file $file exists.  Note: As from PHP8, 'DOCUMENT_ROOT' must be enclosed within SQUARE BRACKETS, not braces as suggested by ferodano at gmail dot com

Or, if not using WP, replace home_url() above with the absolute URL name, eg. 'https://mywebsite.com' - within quotes and no trailing foreslash.

Avee ¶

14 years ago

I made a bit of code that sees whether a file served via RTSP is there or not:

function rtsp_exists($url) {$server = parse_url($url, PHP_URL_HOST);
    $port = "554";
    $hdrs = "DESCRIBE " .$url ." RTSP/1.0"."\r\n\r\n";//Open connection (15s timeout)
    $sh = fsockopen($server, $port, $err, $err_otp, 15);
    //Check connections
    if(!$sh) return false;
    //Send headers
    fputs($sh,$hdrs);
    //Receive data (1KB)
    $rtds = fgets($sh, 1024);
    //Close socket
    fclose($sh);

    return

trevorhawes2 at gmail dot com ¶

1 year ago

NB: This function expects the full server-related pathname to work.

For example, if you run a PHP routine from within, for example, the root folder of your website and and ask:

$bstr = file_exists("/images/Proofreading_patients.jpg");

You will get FALSE even if that file does exist off root.

You need to add

$bstr = file_exists(__DIR_."/images/Proofreading_patients.jpg");

to get it to return TRUE - ie : /srv/www/mywebsite.com/public/images/Proofreading_patients.jpg

marufit at gmail dot com ¶

14 years ago

Older php (v4.x) do not work with get_headers() function. So I made this one and working.

function url_exists($url) {
    // Version 4.x supported
    $handle   = curl_init($url);
    if (false === $handle)
    {
        return false;
    }
    curl_setopt($handle, CURLOPT_HEADER, false);
    curl_setopt($handle, CURLOPT_FAILONERROR, true);  // this works
    curl_setopt($handle, CURLOPT_NOBODY, true);
    curl_setopt($handle, CURLOPT_RETURNTRANSFER, false);
    $connectable = curl_exec($handle);
    curl_close($handle);   
    return $connectable;
}
?>

ferodano at gmail dot com ¶

12 years ago

You could use document root to be on the safer side because the function does not take relative paths:

if( file_exists( $_SERVER{'DOCUMENT_ROOT'} . "/my_images/abc.jpg"))  {
   ...
}
?>

Do not forget to put the slash '/', e.g. my doc root in Ubuntu is /var/www without the slash.

andrewNOSPAMPLEASE at abcd dot NOSPAMERSca ¶

17 years ago

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 ¶

17 years ago

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:

// .htaccess php_value include_path '/home/user/public_html/';

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

//doesn't work, file_exists returns false

broken at links dot com ¶

8 years ago

file_exists() will return FALSE for broken links

$ ln -s does_not_exist my_link
$ ls -l
lrwxr-xr-x   1 user  group    14 May 13 17:28 my_link -> does_not_exist
$ php -r "var_dump(file_exists('my_link'));"
bool(false)

fabin dot gnu at gmail dot com ¶

13 years ago

The code can be used to t a filename that can be used to create a new filename.

function generateRandomString($length = 8)
{   
    $string = ""; //character that can be used
    $possible = "0123456789bcdfghjkmnpqrstvwxyz";

        for(

ihoss dot com at gmail dot com ¶

16 years ago

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.
  $img = "images/".$_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);
?>

kevin at cuznersoft dot com ¶

13 years ago

My way of making sure files exist before including them is as follows (example: including a class file in an autoloader):

function __autoload($name)
{   
    $path = explode(":", ini_get('include_path')); //get all the possible paths to the file (preloaded with the file structure of the project)
    foreach($path as $tryThis)
    {
        //try each possible iteration of the file name and use the first one that comes up
        // name.class.php first
        $exists = file_exists($tryThis . '/' . $name . '.class.php');
        if ($exists)
        {
            include_once($name . '.class.php');
            return;
        } //ok that didn't work, try the other way around
        $exists = file_exists($tryThis . '/' . 'class.' . $name . '.php');
        if ($exists)
        {
            include_once('class.' . $name . '.php');
            return;
        } //neither did that...let's try as an inc.php
        $exists = file_exists($tryThis . '/' . $name . '.inc.php');
        if ($exists)
        {
            include_once($name . '.inc.php');
            return;
        }
    } // can't find it...
    die("Class $name could not be found!");
}
?>

tma at 2p dot cz ¶

17 years ago

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
?>

varrg ¶

3 years ago

file_exists() is vulnerable to race conditions and clearstatcache() is not adequate to avoid it.

The following function is a good solution:

function file_exists_safe($file) {
    if (!$fd = fopen($file, 'xb')) {
        return true;  // the file already exists
    }
    fclose($fd);  // the file is now created, we don't need the file handler
    return false;
}
?>

The function will create a file if non-existent, following calls will fail because the file exists (in effect being a lock).

IMPORTANT: The file will remain on the disk if it was successfully created and you must clean up after you, f.ex. remove it or overwrite it. This step is purposely omitted from the function as to let scripts do calculations all the while being sure the file won't be "seized" by another process.

NOTE: This method fails if the above function is not used for checking in all other scripts/processes as it doesn't actually lock the file.
FIX: You could flock() the file to prevent that (although all other scripts similarly must check it with flock() then, see https://www.php.net/manual/en/function.flock.php). Be sure to unlock and fclose() the file AFTER you're done with it, and not within the above function:

function create_and_lock($file) {
    if (!$fd = fopen($file, 'xb')) {
        return false;
    }
    if (!flock($fd, LOCK_EX|LOCK_NB)) {  // may fail for other reasons, LOCK_NB will prevent blocking
        fclose($fd);
        unlink($file);  // clean up
        return false;
    }
    return $fd;
}

if (