realpath

(PHP 4, PHP 5)

realpath -- 返回规范化的绝对路径名

说明

string realpath ( string path )

realpath() 扩展所有的符号连接并且处理输入的 path 中的 '/./', '/../' 以及多余的 '/' 并返回规范化后的绝对路径名。返回的路径中没有符号连接,'/./' 或 '/../' 成分。

realpath() 失败时返回 FALSE,比如说文件不存在的话。在 BSD 系统上,如果仅仅是 path 不存在的话,PHP 并不会像其它系统那样返回 FALSE

例子 1. realpath() 例子

<?php
$real_path
= realpath("../../index.php");
?>

参见 basename()dirname()pathinfo()


add a note add a note User Contributed Notes
bart at mediawave dot nl
22-Sep-2005 02:31
Here's another function that resolves references to '/./', '/../' and extra '/' characters in the input path and returns the canonicalized pathname.

<?php

function cleanPath($path) {
  
$result = array();
  
// $pathA = preg_split('/[\/\\\]/', $path);
  
$pathA = explode('/', $path);
   if (!
$pathA[0])
      
$result[] = '';
   foreach (
$pathA AS $key => $dir) {
       if (
$dir == '..') {
           if (
end($result) == '..') {
              
$result[] = '..';
           } elseif (!
array_pop($result)) {
              
$result[] = '..';
           }
       } elseif (
$dir && $dir != '.') {
          
$result[] = $dir;
       }
   }
   if (!
end($pathA))
      
$result[] = '';
   return
implode('/', $result);
}

echo
'input:  ', $path = '..//./../dir4//./dir5/dir6/..//dir7/', '<br />';
echo
'output: ', cleanPath($path), '<br />';

?>

Will return:

input:  ..//./../dir4//./dir5/dir6/..//dir7/
output: ../../dir4/dir5/dir7/
Jonny Rylands
15-Sep-2005 06:19
Having problems with includes within include files,
particularly when the include files are in different directories?

This syntax allows:

* relative paths to be used in include strings.
* include files to include other files in different directories.

without getting file not found errors.

<?
 
include_once realpath(dirname(__FILE__)."/relative/path/to/include.inc.php");
?>
Tyron Madlener
15-Aug-2005 03:53
None of the functions provided here worked for me. All of them somehow had the problem with pathes like '../../downloads/bar/../foo/..' or didn't provide relative paths.
So I coded my one that justs removes '.'-dirs from the paths and simplifies stuff like 'dir/..'

function SimplifyPath($path) {
  $dirs = explode('/',$path);

  for($i=0; $i<count($dirs);$i++) {
   if($dirs[$i]=="." || $dirs[$i]=="") {
     array_splice($dirs,$i,1);
     $i--;
   }

   if($dirs[$i]=="..") {
     $cnt = count($dirs);
     $dirs=Simplify($dirs, $i);
     $i-= $cnt-count($dirs);
   }
  }
  return implode('/',$dirs);
}

function Simplify($dirs, $idx) {
  if($idx==0) return $dirs;

  if($dirs[$idx-1]=="..") Simplify($dirs, $idx-1);
  else  array_splice($dirs,$idx-1,2);

  return $dirs;
}

I just wonder why all the other solutions are so complex and that mine so simple, because in general the problem of simplifieng isn't that hard to solve. Well, I hope that there aren't any cases on which my solution fails. Otherwise, feel free to improve :D
phpnote at web-milk dot co dot uk
22-Jul-2005 10:01
I have written this function so that it does not matter whether the folder exists on the system.  It simply traverses the given path moving up directories at every "/.." that it encounters.  Though this can be used with a file at the end I would be cautious about using it with a query attached as any "/.." in the query will remove the text proir until the previous "/".

<?php
function htmlpath($relative_path)
{
      
$realpath = '';
      
$q = 0;

      
// Remove any ./
      
$relative_path = str_replace('/./', '/', $relative_path);
      
// Remove trailing /
      
if ($relative_path[strlen($relative_path)-1] == '/')
       {
              
$relative_path = substr($relative_path, 0, -1);
       }

      
$p = strpos($relative_path, '/..', $q);
       while (
$p !== false)
       {
              
// Get the next part of the path
              
if ($p != $q) $realpath .= substr($relative_path, $q, $p);

              
// Find the edge of the previous directory
              
$i = strrpos($realpath, '/');
               if (
$i === false)
               {
                       return
false// Not enough directories to go up any further.
              
}

              
// Remove the directory
              
$realpath = substr($realpath, 0, $i);
              
// Take out the "/.."
              
$relative_path = substr($relative_path, 0, $p) . substr($relative_path, $p+3);

              
// Find the next "/.."
              
$q = $p;
              
$p = strpos($relative_path, '/..', $q);
       }

      
// Get the rest of the relative path.
      
$realpath .= substr($relative_path, $q);
       return
$realpath;
}
?>
php.netatjulian-lemburg.de
20-Jul-2005 11:55
You have a realpath.
Now you want a htmlpath.

First Suggestion:
<?php

function htmlpath($relative_path) {
  
$realpath=realpath($relative_path);
  
$htmlpath=str_replace($_SERVER['DOCUMENT_ROOT'],'',$realpath);
   return
$htmlpath;
}
?>

But this does not work on some servers.

Second Suggestion:

<?php

function htmlpath($realpath) {
  
$i = substr_count($_ENV["SCRIPT_URL"],'/')."<br>";
  
$baserealpath=realpath(str_repeat('../',$i-1));
  
$htmlpath=str_replace($baserealpath,'',$realpath);
   return
$htmlpath;
}

?>
Lars Scheithauer <l dot scheithauer at gmx dot de>
09-Jun-2005 01:44
This function is also nice to test for security-breaches. You can forbid the script to access files below a certain directory to prevent "../../../etc/shadow" and similar attacks:

<?php

// declare the basic directory for security reasons
// Please do NOT attach a "/"-suffix !
$basedir = '/var/www/cgi-bin/scriptfolder';

// compare the entered path with the basedir
$path_parts = pathinfo($_REQUEST['file_to_get']);
if (
realpath($path_parts['dirname']) != $basedir) {
  
/* appropriate action against crack-attempt*/
  
die ('coding good - h4x1ng bad!');
}

?>

The url "script.php?file_to_get=../../../etc/shadow" will now result in an error.
pulstar at ig dot com dot br
21-Dec-2004 05:43
Sometimes you may need to refer to the absolute path of a file in your website instead of a relative path, but the realpath() function returns the path relative to the server's filesystem, not a path relative to your website root directory.

For example, realpath() may return something like this:

/home/yoursite/public_html/dir1/file.ext

You can't use this in an HTML document, because the web server will not find the file. To do so, you can use:

<?php

function htmlpath($relative_path) {
  
$realpath=realpath($relative_path);
  
$htmlpath=str_replace($_SERVER['DOCUMENT_ROOT'],'',$realpath);
   return
$htmlpath;
}

echo
'<img src="',htmlpath('../../relative/path/to/file.ext'),'" border=1>';

?>

It will return something like:

<img src="/dir1/relative/path/to/file.ext" border=1>
carlosreche at yahoo dot com
16-Dec-2004 07:52
In my last function, it will always discard "../" if there are no more parent dirs to go back. But it's a mistake! For example, relative paths like "../../downloads" returns "downloads/", and it should return exactly the same entry (because parent directories for "downloads" may exist in this case). Well, I've corrected this bug. Now:

"C:/downloads/../../../" returns "C:/"
"downloads/../../../"  returns  "../../"

<?php

function real_path($path)
{
   if (
$path == "")
   {
       return
false;
   }

  
$path = trim(preg_replace("/\\\\/", "/", (string)$path));

   if (!
preg_match("/(\.\w{1,4})$/", $path)  && 
       !
preg_match("/\?[^\\/]+$/", $path)  && 
       !
preg_match("/\\/$/", $path))
   {
      
$path .= '/';
   }

  
$pattern = "/^(\\/|\w:\\/|https?:\\/\\/[^\\/]+\\/)?(.*)$/i";

  
preg_match_all($pattern, $path, $matches, PREG_SET_ORDER);

  
$path_tok_1 = $matches[0][1];
  
$path_tok_2 = $matches[0][2];

  
$path_tok_2 = preg_replace(
                   array(
"/^\\/+/", "/\\/+/"),
                   array(
"", "/"),
                  
$path_tok_2);

  
$path_parts = explode("/", $path_tok_2);
  
$real_path_parts = array();

   for (
$i = 0, $real_path_parts = array(); $i < count($path_parts); $i++)
   {
       if (
$path_parts[$i] == '.')
       {
           continue;
       }
       else if (
$path_parts[$i] == '..')
       {
           if (  (isset(
$real_path_parts[0])  &&  $real_path_parts[0] != '..')
               || (
$path_tok_1 != "")  )
           {
              
array_pop($real_path_parts);
               continue;
           }
       }

      
array_push($real_path_parts, $path_parts[$i]);
   }

   return
$path_tok_1 . implode('/', $real_path_parts);
}

?>
ash at spamless dot theleys dot net
20-Nov-2004 01:37
sarizmendi is right, and this is very frustrating. I'm trying to use a script with a different virtual root, which process folders/contents. This works perfectly with asp's server.mappath() but realpath() fails, because it's mapping to the same doc root (C:\inetpub\wwwroot) when it should be from a different virtual path (i.e. D:\content). Although I could force this to the static path, I'm trying to use it with a $_GET, and this could point to any of a number of virtual roots.
ilgarm -at- azeronline.com
12-Mar-2004 03:43
I've tested several examples given by other ppls but none were working, at least on windows. so I spent time and wrote my own function for realpath( ) replacement that will work with non-existing paths also.
Here it is. Please, check it, if you have time and let me know about the results. Thanks.

<?php

define
( "_PL_OS_SEP", "/" );
define( "_CUR_OS", substr( php_uname( ), 0, 7 ) == "Windows" ? "Win" : "_Nix" );

function
checkCurrentOS( $_OS )
{
   if (
strcmp( $_OS, _CUR_OS ) == 0 ) {
       return
true;
   }
   return
false;
}

function
isRelative( $_dir )
{
   if (
checkCurrentOS( "Win" ) ) {
       return (
preg_match( "/^\w+:/", $_dir ) <= 0 );
   }
   else {
       return (
preg_match( "/^\//", $_dir ) <= 0 );
   }
}

function
unifyPath( $_path )
{
   if (
checkCurrentOS( "Win" ) ) {
       return
str_replace( "\\", _PL_OS_SEP, $_path );
   }
   return
$_path;
}

function
getRealpath( $_path )
{
  
/*
     * This is the starting point of the system root.
     * Left empty for UNIX based and Mac.
     * For Windows this is drive letter and semicolon.
     */
  
$__path = $_path;
   if (
isRelative( $_path ) ) {
      
$__curdir = unifyPath( realpath( "." ) . _PL_OS_SEP );
      
$__path = $__curdir . $__path;
   }
  
$__startPoint = "";
   if (
checkCurrentOS( "Win" ) ) {
       list(
$__startPoint, $__path ) = explode( ":", $__path, 2 );
      
$__startPoint .= ":";
   }
  
# From now processing is the same for WIndows and Unix, and hopefully for others.
  
$__realparts = array( );
  
$__parts = explode( _PL_OS_SEP, $__path );
   for (
$i = 0; $i < count( $__parts ); $i++ ) {
       if (
strlen( $__parts[ $i ] ) == 0 || $__parts[ $i ] == "." ) {
           continue;
       }
       if (
$__parts[ $i ] == ".." ) {
           if (
count( $__realparts ) > 0 ) {
              
array_pop( $__realparts );
           }
       }
       else {
          
array_push( $__realparts, $__parts[ $i ] );
       }
   }
   return
$__startPoint . _PL_OS_SEP . implode( _PL_OS_SEP, $__realparts );
}

echo
"getRealpath ../../x: ". getRealpath( "../../x" ) . "<BR>\n";
echo
"getRealpath ./../x: ". getRealpath( "./../x" ) . "<BR>\n";
echo
"getRealpath x: ". getRealpath( "x" ) . "<BR>\n";
echo
"getRealpath /../x: ". getRealpath( "/../x" ) . "<BR>\n";
echo
"getRealpath d:/../../x: ". getRealpath( "d:/../../x" ) . "<BR>\n";
echo
"getRealpath ./../xx/xxx/.////../yyy: ". getRealpath( "./../xx/xxx/.////../yyy" ) . "<BR>\n";

?>
eric at themepark dot com
18-Jul-2002 09:15
note that realpath() will chop any trailing delimiter like \ or / ...don't forget to add it back on if you need it.

Eric Mueller - themepark.com
jemptyg at rwmc dot net
06-Jul-2001 06:38
realpath() seems to be equivalent to ASP's Server.MapPath.  On my Win2k box I have successfully used realpath() to give me the full path for a file outside of the document_root.  This will be very useful in conjunction with is_dir and/or is_file, which require a full path.
jerome at dot451 dot com
29-Aug-2000 03:03
mkdir (and realpath) did not work because i'd used virtual() function to replace server side include in my file.
And i've just seen that virtual() function changes the current directory ... that's why !

jerome ;)