WordPress network sunrise.php for multiple environments with a single database

sunrise.php

<?php

// Check the current host or server name
if (isset($_SERVER['HTTP_HOST'])) {
	$host = $_SERVER['HTTP_HOST'];
} elseif (isset($_SERVER['SERVER_NAME'])) {
	$host = $_SERVER['SERVER_NAME'];
}

// Switch the host to the desired domain
if ( DOMAIN_CURRENT_SITE == $host && WP_LOCAL_DEV ) {
	$host = 'staging.example.com';
}

if (is_subdomain_install()) {
	$sql = $wpdb -> prepare("SELECT * FROM {$wpdb->blogs} WHERE domain = %s LIMIT 1", $host);
} else {
	// Get the path from the URl
	$path = explode('/', ltrim($_SERVER['REQUEST_URI'], '/'));
	if (count($path))
		$path = '/' . $path[0];
	else
		$path = '/';

	$sql = $wpdb -> prepare("SELECT * FROM {$wpdb->blogs} WHERE path in ('{$path}', '{$path}/') AND domain = %s LIMIT 1", $host, $path);

}

if ($_blog = $wpdb -> get_row($sql)) {
	
	$current_blog = $_blog;

	$blog_id = $_blog -> blog_id;
	$site_id = $current_blog -> site_id;

	// set current site
	$current_site = $wpdb -> get_row($wpdb -> prepare("SELECT * from {$wpdb->site} WHERE id = %d", $site_id));
	$current_site -> blog_id = $blog_id;

	$current_site = get_current_site_name($current_site);
}

Credit for this goes to chrisguitarguy for his answer on Stack Exchange.

get_current_site_name is deprecated since Wordpress 3.9