HTML and CSS Reference
In-Depth Information
CHAPTER 5
WebSockets
Every HTTP request sent from the browser includes headers, whether you want them
or not. Nor are they small headers. Uncompressed request and response headers can
vary in size from 200 bytes to over 2K. Although, typical size is somewhere between 700
and 900 bytes, those numbers will grow as
userAgent
s expand features.
WebSockets give you minimal overhead and a much more efficient way of delivering
data to the client and server with full duplex communication through a single socket.
The WebSocket connection is made after a small HTTP handshake occurs between the
client and the server, over the same underlying TCP/IP connection. This gives you an
open connection between the client and the server, and both parties can start sending
data at any time.
A few of WebSockets' many advantages are:
• No HTTP headers
• No lag due to keep-alive issues
• Low latency, better throughput and responsiveness
• Easier on mobile device batteries
Building the Stack
To effectively develop any application with WebSockets, you must accept the idea of the
“real-time Web” in which the client-side code of your web application communicates
continuously with a corresponding real-time server during every user connection. To
