is-staging-site.php

function is_staging_site_for_domain( $domain, $staging ) {
	$parsed_domain  = parse_url( $domain );
	$parsed_staging = parse_url( $staging );
	
	$preg_quoted_domain_host = preg_quote( $domain['host'], '/' );
	
	// If it's a local. dev. preprod. or staging. subdomain…
	if ( preg_match( '/(local|dev|preprod|staging)\.' . $preg_quoted_domain_host . '/i', $parsed_staging['host'] ) ) {
		return true;
	}

	if ( preg_match( '/' . $preg_quoted_domain_host . '\.wpstagecoach.com/i', $parsed_staging['host'] ) ) {
		return true;
	}

	return false;
}