is_readable

is_file

[edit] Last updated: Fri, 18 Sep 2009

is_link

(PHP 4, PHP 5)

is_link — Казва дали filename е символна връзка (symbolic link)

Описание

bool is_link ( string $filename )

Казва дали filename е символна връзка (symbolic link).

Параметри

filename: Път до файла.

Връщани стойности

Връща TRUE ако filename съществува и е символна връзка или FALSE в противен случай.

Примери

Example #1 Създава символична връзка или потвърждава, че е такава


<?php
$link = 'uploads';

if(is_link($link))
{
    echo(readlink($link));
}
else
{
    symlink('uploads.php', $link);
}
?>

Бележки

Забележка: Резултатите от тази функция са кеширани. Виж clearstatcache() за повече подробности.

Съвет

От PHP 5.0.0 тази функция може също да бъде използвана с някои URL опаковачи (wrappers). Виж List of Supported Protocols/Wrappers за списък с опаковачите, които поддържат stat() семейството от функции.

Вж. също

is_dir() - Проверява дали дадено име на файл е директория
is_file() - Казва дали filename е обикновен файл
readlink() - Връща името на файла сочен от символична връзка

is_readable

is_file

[edit] Last updated: Fri, 18 Sep 2009

add a note User Contributed Notes is_link

PaulE 01-Jun-2009 08:03


A workaround for Windows LNK files:





<?php





function _is_link($filename)


{


    if(is_link($filename))


        return true;





    $ext = substr(strrchr($filename, '.'), 1);


    if(strtolower($ext) == 'lnk')


    {


        return (_readlink($filename) ? true : false);


    }





    return false;


}





function _readlink($file)


{


    if(file_exists($file))


    {


        if(is_link($file))


        {


            return readlink($file);


        }





        // Get file content


        $handle = fopen($file, "rb");


        $buffer = array();





        while(!feof($handle))


        {


            $buffer[] = fread($handle, 1);


        }





        fclose($handle);





        // Test magic value and GUID


        if(count($buffer) < 20)


            return false;


        if($buffer[0] != 'L')


            return false;


        if((ord($buffer[4]) != 0x01) ||


           (ord($buffer[5]) != 0x14) ||


           (ord($buffer[6]) != 0x02) ||


           (ord($buffer[7]) != 0x00) ||


           (ord($buffer[8]) != 0x00) ||


           (ord($buffer[9]) != 0x00) ||


           (ord($buffer[10]) != 0x00) ||


           (ord($buffer[11]) != 0x00) ||


           (ord($buffer[12]) != 0xC0) ||


           (ord($buffer[13]) != 0x00) ||


           (ord($buffer[14]) != 0x00) ||


           (ord($buffer[15]) != 0x00) ||


           (ord($buffer[16]) != 0x00) ||


           (ord($buffer[17]) != 0x00) ||


           (ord($buffer[18]) != 0x00) ||


           (ord($buffer[19]) != 0x46))


        {


            return false;


        }





        $i = 20;


        if(count($buffer) < ($i + 4))


            return false;





        $flags = ord($buffer[$i]);


        $flags = $flags | (ord($buffer[++$i]) << 8);


        $flags = $flags | (ord($buffer[++$i]) << 16);


        $flags = $flags | (ord($buffer[++$i]) << 24);





        $hasShellItemIdList = ($flags & 0x00000001) ? true : false;


        $pointsToFileOrDir = ($flags & 0x00000002) ? true : false;





        if(!$pointsToFileOrDir)


            return false;





        if($hasShellItemIdList)


        {


            $i = 76;


            if(count($buffer) < ($i + 2))


                return false;





            $a = ord($buffer[$i]);


            $a = $a | (ord($buffer[++$i]) << 8);


            


        }





        $i = 78 + 4 + $a;


        if(count($buffer) < ($i + 4))


            return false;





        $b = ord($buffer[$i]);


        $b = $b | (ord($buffer[++$i]) << 8);


        $b = $b | (ord($buffer[++$i]) << 16);


        $b = $b | (ord($buffer[++$i]) << 24);





        $i = 78 + $a + $b;


        if(count($buffer) < ($i + 4))


            return false;





        $c = ord($buffer[$i]);


        $c = $c | (ord($buffer[++$i]) << 8);


        $c = $c | (ord($buffer[++$i]) << 16);


        $c = $c | (ord($buffer[++$i]) << 24);





        $i = 78 + $a + $b + $c;


        if(count($buffer) < ($i +1))


            return false;





        $linkedTarget = "";


        for(;$i < count($buffer); ++$i)


        {


            if(!ord($buffer[$i]))


                break;





            $linkedTarget .= $buffer[$i];


        }





        if(empty($linkedTarget))


            return false;





        


        return $linkedTarget;


    }





    return false;


}





if(_is_link('test.lnk'))


{


    echo _readlink('test.lnk');


}


?>

foobarfarter 18-Oct-2008 09:06


@radon8472 at hotmail dot com

The windows .lnk-things are real files, the explorer only treats them like links. Try to open one with Win+R->"notepad X:\Path\Visiblefilename.lnk You will see much 0-Bytes, but the linked path is displayed right on the screen. It should be possible to do the same by php.

radon8472 at hotmail dot com 31-Jul-2008 03:38


This function returns "false" for windows *.lnk files (tested under windows XP). 



filetype also returns "file" an not "link" like expected.



I didn`t find a solution for this.

mbirth at webwriters dot de 20-May-2008 02:24


To find out whether a file is hardlinked to another filename, check the number of links of the stat() output. If it is >1 there is another filename for that file.



To find out whether two filenames are pointing to the same file, check the inode number of those 2 filenames. If it is equal, the 2 filenames are hardlinked together.

neverpanic->gmail[com] 29-Dec-2006 07:50


For me (Debian Sarge VPS) is_link returns true even for directories if you don't add a trailing slash to the filename.

<?php

if ($dir{strlen($dir)-1} == '/') $dir = substr($dir, 0, -1);

is_link($dir);

?>

This works for me. It can't detect a symlink somewhere in a complete path, though (i.e. is_link(/www/somedir/file.php) will return false, just as is_link(/www/) would)

brendy at gmail dot com 05-May-2006 01:22


On Mac OSX, to see if a file is a FInder alias:



<?PHP

if( getFinderAlias( $someFile , $target ) ) {

 echo $target;

}

else {

 echo "File is not an alias";

}



function getFinderAlias( $filename , &$target ) {

$getAliasTarget = <<< HEREDOC

    -- BEGIN APPLESCRIPT --

    set checkFileStr to "{$filename}"

    set checkFile to checkFileStr as POSIX file

    try

        tell application "Finder"

            if original item of file checkFile exists then

                set targetFile to (original item of file checkFile) as alias

                set posTargetFile to POSIX path of targetFile as text

                get posTargetFile

            end if

        end tell

    end try

    -- END APPLESCRIPT --

HEREDOC;

$runText = "osascript << EOS\n{$getAliasTarget}\nEOS\n";

$target = trim( shell_exec( $runText ) );

return ( $target == "" ? false : true );

}

?>

jr at cnb dot uam dot es 30-May-2005 05:31


Why don't you just try



is_dir("$pathname/.")



instead?



If $pathname is a directory, $pathname/. is itself and is a directory too.



If $pathname is a link to a directory, then $pathname/. is the actual directory pointed at and is a directory as well.



If $pathname is a link to a non-directory, then $pathname/. does not exist and returns FALSE, as it should.



A lot easier, more readable and intuitive.

andudi at gmx dot ch 02-Jun-2002 04:44


On my SuSE 7.2 is_link does not work on directories, but to find out, if a dir is a link, I use now this:



$linkdir = $path.$linkdirname;

if (realpath($linkdir) != realpath($path)."/".$linkdirname):

//$linkdir is a symbolic linked dir!

...



and this works fine :-)



Andreas Dick

aris at riponce dot com 26-Mar-2001 07:27


If you test a symbolic (soft) link with is_file() it will return true. Either use filetype() which always returns the correct type OR make sure that you FIRST test with is_link() before you do with is_file() to get the correct type.

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