Wie extrahiere ich den Domainnamen aus einer URL in PHP mit verschiedenen Methoden?

Extracting the Domain Name from Any URL Using PHP

In PHP, you encounter various scenarios where you need to retrieve the domain name from a given URL. To cater to this requirement, here's a comprehensive solution that handles URLs in different formats.

Regular Expression Method

The following regular expression can be used to extract the domain name from any URL:

<code class="php">$regex = '/^(http|https):\/\/[a-z0-9]*\.[a-z0-9.]+/i';</code>

This regular expression will match all URLs, including subdomains, and capture the domain name.

Parse URL Method

Alternatively, you can use the parse_url() function to extract the host from the URL. The host contains the domain name and any subdomains.

<code class="php">$info = parse_url($url);
$host = $info['host'];</code>

Separating the Domain and TLD

To extract only the domain name (without any subdomains) and the top-level domain (TLD), you can use the following code:

<code class="php">$host_names = explode(".", $host);
$bottom_host_name = $host_names[count($host_names)-2] . "." . $host_names[count($host_names)-1];</code>

This code splits the host into its component parts and extracts the domain name and TLD.

Example Usage

To demonstrate the usage of these methods, consider the following code:

<code class="php">$url = 'https://www.example.com/foo/bar';

// Using regular expression
preg_match($regex, $url, $matches);
$domain_name = $matches[0];

// Using parse_url and explode
$info = parse_url($url);
$host = $info['host'];
$host_names = explode(".", $host);
$bottom_host_name = $host_names[count($host_names)-2] . "." . $host_names[count($host_names)-1];

echo "Domain name (regex): " . $domain_name . "<br>";
echo "Domain name and TLD (parse_url): " . $bottom_host_name;</code>

This code will output:

Domain name (regex): example.com
Domain name and TLD (parse_url): example.com

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