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How to Combine is_link() and realpath() to Get the Real Path of a File? Step-by-Step Guide

M66 2025-07-18

In PHP development, handling file paths is a common task, especially when dealing with symbolic links (symlinks). Accurately obtaining the real path of a file becomes particularly crucial. This article will provide a detailed guide on how to combine is_link() and realpath() functions to retrieve the real path of a file.

1. Why Combine is_link() and realpath()?

  • is_link(): Checks whether the specified path is a symbolic link.

  • realpath(): Returns the absolute path of a given path, resolving all symbolic links.

Using realpath() alone can directly give the real path of a file, but in some cases, we may want to first check if it's a symbolic link before deciding how to handle the path.

2. Example Code Explanation

<?php
// Assume we have a file path
$filePath = '/var/www/html/symlink-file';
<p>// First, check if the path is a symbolic link<br>
if (is_link($filePath)) {<br>
// If it is a symbolic link, use readlink() to get the path it points to<br>
$linkTarget = readlink($filePath);</p>
$realPath = realpath($linkTarget);

} else {
// If it is not a symbolic link, directly get the real path
$realPath = realpath($filePath);
}

echo "The real path of the file is: " . $realPath;
?>

In the above code:

  1. We use is_link() to check if the file is a symbolic link.

  2. If it is a symbolic link, we first use readlink() to get the path it points to.

  3. Then we use realpath() to get the absolute real path of the link target.

  4. If it is not a symbolic link, we directly use realpath() to get the real path.

3. Example of Combining with Actual URL

If you need to handle a remote file URL in PHP code, and the URL involves redirection or symbolic links, you can parse the path before proceeding with operations.

Example code:

<?php
$url = 'http://m66.net/path/to/symlink';
<p>// First, parse the URL to get the path part<br>
$parsedUrl = parse_url($url);<br>
$path = $parsedUrl['path'] ?? '';</p>
<p>// Here, assume the same path exists locally, and we check it<br>
if (is_link($path)) {<br>
$linkTarget = readlink($path);<br>
$realPath = realpath($linkTarget);<br>
} else {<br>
$realPath = realpath($path);<br>
}</p>
<p>echo "The real path of the corresponding file is: " . $realPath;<br>
?><br>

The above code demonstrates how to combine the path part of a URL with is_link() and realpath() to retrieve the real path.

4. Notes

  • realpath() will return false if the path does not exist.

  • readlink() can only be used for symbolic links, not regular files.

  • For remote URLs, is_link() and realpath() are not applicable and must be used in the local file system.

In summary, combining is_link() and realpath() allows you to more accurately determine if a file is a symbolic link and retrieve its real path, preventing potential issues caused by incorrect paths. This is particularly useful in file operations, configuration management, and similar scenarios.

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