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WebSocket by Andrew Lombardi

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Chapter 8. WebSocket Protocol

No discussion about protocols, especially ones that are initiated via an HTTP call, would be complete without talking a bit about the history of HTTP. The inception of WebSocket came about because of the massive popularity of Ajax and real-time updates. With HTTP, a protocol where a client requests a resource, and the server responds with the resource or possibly an error code if something went wrong. This unidirectional nature has been worked around by using technologies like Comet and long polling, but comes at a cost of computing resources on the server side. WebSocket seeks to be one of the techniques that solves this problem and allows web developers to implement bidirectional communication over the same HTTP request.

HTTP 0.9—The Web Is Born

The birth of the World Wide Web brought rise to the first versions of the Hypertext Transfer Protocol (HTTP). The first version of HTTP was conjured up by Tim Berners-Lee in conjunction with the Hypertext Markup Language (HTML). HTTP 0.9 was incredibly simple. A client requests content via the GET method:

GET /index.html

The simplicity of HTTP 0.9 meant that you could request only two things: plain text or HTML. This initial version of HTTP didn’t have headers, so there was no ability to serve any media. In essence, as a client you requested a resource from the server using TCP, and after the server was done sending it, the connection was closed.

HTTP 1.0 and 1.1

The simplicity in 0.9 was not going to ...

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