You’re trying to read the URL of the current web page you’re visiting.
At first, let’s see different parts of a URL. A URL may have the following parts-
Protocol: http or https is the protocol. In the above picture, https is the protocol.
Domain: After://, domain starts and end till the next forward slash(/). The domain part may include sub-domain. In the above image, php.net is the domain.
Path: After domain, the path refers to the path of the script you’re currently on.
PHP stores URL information in $_SERVER array
Web server stores URL path of a webpage you visit along with other information in the $_SERVER array. Each part of the URL that you see in the above picture is saved in each different index in the $_SERVER array. $_SERVER is an associative array.
Retrieve URL path information
To retrieve different parts of an URL, use different indices in the $_SERVER array.
The following picture shows parts of an URL and $_SERVER arrays with different keys to retrieve those URL parts. Compare matching the colors.
Let’s see the PHP code to read full path of the current web page URL-
<?php echo isset($_SERVER['HTTPS']) ? 'https://' : 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI']; ?>