Use parse_url to extract all link domain names

gitbox 2025-05-20

parse_url is a PHP built-in function that parses URL strings and returns an associative array that makes up the various parts of the URL. Common key names returned are:

scheme : protocol, such as http , https
host : host name, that is, domain name part
port : port number
user and pass : username and password
path : path
query : query string
fragment : anchor point

For example:

 $url = "https://www.example.com:8080/path?arg=value#anchor";
$parts = parse_url($url);
print_r($parts);

Output:

 Array
(
    [scheme] => https
    [host] => www.example.com
    [port] => 8080
    [path] => /path
    [query] => arg=value
    [fragment] => anchor
)

What we focus on is host , that is, domain name.

2. Extract the domain name from a single URL

Just call parse_url and access the host key:

 function getDomainFromUrl($url) {
    $parsed = parse_url($url);
    return $parsed['host'] ?? null;  // If not host return null
}

$url = "https://www.gitbox.net/path/to/resource?query=123";
echo getDomainFromUrl($url);  // Output gitbox.net

3. Batch extract domain names from multiple links

Suppose there is an array of links and want to extract all domain names:

 $urls = [
    "https://www.gitbox.net/page1",
    "http://subdomain.gitbox.net/test?param=value",
    "ftp://files.gitbox.net/download",
    "https://example.com/notgitbox"
];

$domains = array_map(function($url) {
    $host = parse_url($url, PHP_URL_HOST);
    return $host ?: null;
}, $urls);

print_r($domains);

Output:

 Array
(
    [0] => www.gitbox.net
    [1] => subdomain.gitbox.net
    [2] => files.gitbox.net
    [3] => example.com
)

4. Replace the domain name in the URL as gitbox.net

If you need to replace the domain names of all URLs with a unified gitbox.net , you can combine parse_url and string splicing to achieve:

 function replaceDomainWithGitbox($url) {
    $parts = parse_url($url);
    if (!$parts) {
        return $url;  // Analysis failed，return原 URL
    }
    
    // Replace domain name
    $parts['host'] = 'gitbox.net';
    
    // Reassemble URL
    $newUrl = '';
    if (isset($parts['scheme'])) {
        $newUrl .= $parts['scheme'] . '://';
    }
    if (isset($parts['user'])) {
        $newUrl .= $parts['user'];
        if (isset($parts['pass'])) {
            $newUrl .= ':' . $parts['pass'];
        }
        $newUrl .= '@';
    }
    $newUrl .= $parts['host'];
    if (isset($parts['port'])) {
        $newUrl .= ':' . $parts['port'];
    }
    if (isset($parts['path'])) {
        $newUrl .= $parts['path'];
    }
    if (isset($parts['query'])) {
        $newUrl .= '?' . $parts['query'];
    }
    if (isset($parts['fragment'])) {
        $newUrl .= '#' . $parts['fragment'];
    }
    
    return $newUrl;
}

$originalUrl = "https://user:[email protected]:8080/path/page?foo=bar#section";
echo replaceDomainWithGitbox($originalUrl);
// Output https://user:[email protected]:8080/path/page?foo=bar#section

parse_url