How to get the relative directory no matter from where it's included in PHP?

Question

If it's Path_To_DocumentRoot/a/b/c.php,should always be /a/b.

I use this:

dirname($_SERVER["PHP_SELF"])

But it won't work when it's included by another file in a different directory.

EDIT

I need a relative path to document root .It's used in web application.

I find there is another question with the same problem,but no accepted answer yet.

PHP - Convert File system path to URL

Answer 1

Do you have access to $_SERVER['SCRIPT_NAME']? If you do, doing:

dirname($_SERVER['SCRIPT_NAME']);

Should work. Otherwise do this:

In PHP < 5.3:

substr(dirname(__FILE__), strlen($_SERVER['DOCUMENT_ROOT']));

Or PHP >= 5.3:

substr(__DIR__, strlen($_SERVER['DOCUMENT_ROOT']));

---

You might need to realpath() and str_replace() all \ to / to make it fully portable, like this:

substr(str_replace('\\', '/', realpath(dirname(__FILE__))), strlen(str_replace('\\', '/', realpath($_SERVER['DOCUMENT_ROOT']))));

Answer 2

PHP < 5.3:

dirname(__FILE__)

PHP >= 5.3:

__DIR__

EDIT:

Here is the code to get path of included file relative to the path of running php file:

    $thispath = explode('\\', str_replace('/','\\', dirname(__FILE__)));
    $rootpath = explode('\\', str_replace('/','\\', dirname($_SERVER["SCRIPT_FILENAME"])));
    $relpath = array();
    $dotted = 0;
    for ($i = 0; $i < count($rootpath); $i++) {
        if ($i >= count($thispath)) {
            $dotted++;
        }
        elseif ($thispath[$i] != $rootpath[$i]) {
            $relpath[] = $thispath[$i]; 
            $dotted++;
        }
    }
    print str_repeat('../', $dotted) . implode('/', array_merge($relpath, array_slice($thispath, count($rootpath))));

Answer 3

Here's a general purpose function to get the relative path between two paths.

/**
 * Return relative path between two sources
 * @param $from
 * @param $to
 * @param string $separator
 * @return string
 */
function relativePath($from, $to, $separator = DIRECTORY_SEPARATOR)
{
    $from   = str_replace(array('/', '\\'), $separator, $from);
    $to     = str_replace(array('/', '\\'), $separator, $to);

    $arFrom = explode($separator, rtrim($from, $separator));
    $arTo = explode($separator, rtrim($to, $separator));
    while(count($arFrom) && count($arTo) && ($arFrom[0] == $arTo[0]))
    {
        array_shift($arFrom);
        array_shift($arTo);
    }

    return str_pad("", count($arFrom) * 3, '..'.$separator).implode($separator, $arTo);
}

Examples

relativePath('c:\temp\foo\bar', 'c:\temp');              // Result: ../../
relativePath('c:\temp\foo\bar', 'c:\\');                 // Result: ../../../
relativePath('c:\temp\foo\bar', 'c:\temp\foo\bar\lala'); // Result: lala

Answer 4

I know this is an old question but the solutions suggested using DOCUMENT_ROOT assume the web folder structure reflects the server folder structure. I have a situation where this isn't the case. My solution is as follows. You can work out how a server address maps to a web address if you have an example from the same mapped area folders. As long as the root php file that included this file is in the same mapped area you have an example.

$_SERVER['SCRIPT_FILENAME'] is the server address of this file and $_SERVER['PHP_SELF'] is the web relative version. Given these two you can work out what the web relative version of your file is from its server address (__FILE__) as follows.

function getCurrentFileUrl() {
    $file = __FILE__;
    $script = $_SERVER['SCRIPT_FILENAME'];
    $phpself = $_SERVER['PHP_SELF'];

    // find end of section of $file which is common to $script
    $i = 0;
    while($file[$i] == $script[$i]) {
        $i++;
    }
    // remove end section of $phpself that is the equivalent to the section of $script not included in $file. 
    $phpself = substr($phpself, 0, strlen($phpself)-(strlen($script)-$i));
    // append end section of $file onto result
    $phpself .= substr($file, $i, strlen($file)-$i);

    // complete address 
    return $_SERVER['REQUEST_SCHEME'].'://'.$_SERVER['SERVER_NAME'].$phpself;
}