[Server] Fix bug

Reject request that without 'Host' header

src/server.ts

@@ -14,6 +14,15 @@ import vhost = require('vhost');
 const app = express();
 app.disable('x-powered-by');
 
+// Reject request that without 'Host' header
+app.use((req, res, next) => {
+	if (!req.headers.host) {
+		res.sendStatus(400);
+	} else {
+		next();
+	}
+});
+
 /**
  * Register modules
  */