Compose URL from $_SERVER in PHP

compose_url.php

<?php 
function compose_url(array $server){
	
	// Scheme
	$scheme = '';
	if (isset($server['SERVER_PROTOCOL'])) {
		$scheme = explode('/', $server['SERVER_PROTOCOL']);
		$scheme = strtolower($scheme[0]);
		if (isset($server['HTTPS']) && 'off' != $server['HTTPS']) {
			$scheme .= 's';
		}
	}

	// Host
	$host = isset($server['HTTP_HOST']) ? $server['HTTP_HOST'] : '';

	// Port
	$port = '';
	if (isset($server['SERVER_PORT']) && '80' != $server['SERVER_PORT']) {
		$port = ':'. (int) $server['SERVER_PORT'];
	}

	// URI
	$uri = '';
	if (isset($server['REQUEST_URI'])) {
		$uri = $server['REQUEST_URI'];
	} else if (isset($server['PHP_SELF'])) {
		$uri = $server['PHP_SELF'];
	}
	
    return $scheme.'://'.$host.$port.$uri;
}