The $_SERVER array is a global variable that contains server and header information.
To get the domain name where you run PHP code, you need to access the SERVER_NAME or HTTP_HOST index from the $_SERVER array.
Suppose your website has the URL of https://example.com/post/1. Here’s how you get the domain name:
<?php
print $_SERVER["SERVER_NAME"];
// Output: example.com
If you are using Apache server 2, you need to configure the directive UseCanonicalName to On and set the ServerName.
Otherwise, the ServerName value reflects the hostname supplied by the client, which can be spoofed.
Aside from the SERVER_NAME index, you can also get the domain name using HTTP_HOST like this:
<?php
print $_SERVER["HTTP_HOST"];
// Output: example.com
The difference is that HTTP_HOST is controlled from the browser, while SERVER_NAME is controlled from the server.
If you need the domain name for business logic, you should use SERVER_NAME because it is more secure.
Finally, you can combine SERVER_NAME with HTTPS and REQUEST_URI indices to get your website’s complete URL.
See the code example below:
<?php
// 1. write the http protocol
$full_url = "http://";
// 2. check if your server use HTTPS
if (isset($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] === "on") {
$full_url = "https://";
}
// 3. append domain name
$full_url .= $_SERVER["SERVER_NAME"];
// 4. append request URI
$full_url .= $_SERVER["REQUEST_URI"];
print $full_url;
// example output: https://example.com/post/1
Now you’ve learned how to get the domain name of your website using PHP. Nice!
