Book Image

DART Cookbook

By : Ivo Balbaert
Book Image

DART Cookbook

By: Ivo Balbaert

Overview of this book

Table of Contents (18 chapters)
Dart Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using WebSockets


This recipe will show you how to use WebSockets in a client-server application (both web and command-line clients) and what its advantages are. You can find the code in the project websockets.

Getting ready

HTTP is a simple request-response-based protocol, and then the connection is broken from the application's point of view until the next request. In a modern web application (for example, in online multiplayer games), the client and server are of equal importance; changes in the state of the application can take place on both sides. So, we need a bi-directional communication channel between the client(s) and the server that allows for two-way real time updates and more interaction; this is exactly what WebSockets has to offer. WebSocket connections between a browser and a server are made through a handshake request. This is a regular HTTP client request with an upgrade flag in the header, also containing a Sec-WebSocket-Key, which is a random value that has been base64 encoded...