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HTTP version evolution

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The HTTP protocol is the communication language between the browser and the server, the latest version has reached HTTP 3.0.

I have read some articles and made some records of the evolution of the HTTP version. here I will share some key points for you

First version HTTP/0.9

First verssion HTTP mainly used for academic communication. used to transfer HTML hypertext content between networks, using a request-response model. a request is sent from the client and the server returns data.

In general the demand at that time was very simple, it was used to transmit small HTML files.

Has three characteristics:

  • There is only one request line. and there is no HTTP request header and request body

  • The server did not return header information

  • The content of the returned file is transmitted as a stream of ASCII characters


Supporting multiple types of file downloads is a core requirement of HTTP/1.0. including JavaScript, CSS, pictures, audio, video etc.

HTTP/1.0 negotiates and communicates through request headers and response headers. requesting file types and returning file types. E.g

// request
accept: text/html
accept-encoding: gzip, deflate, br
accept-Charset: ISO-8859-1,utf-8
accept-language: zh-CN,zh

// response
content-encoding: br
content-type: text/html; charset=UTF-8
Enter fullscreen mode Exit fullscreen mode


HTTP/1.1 has made a lot of updates on the basis of HTTP/1.0 including

  • Improve the persistent connection. multiple HTTP requests can be transmitted on a TCP connection. as long as the browser or server does not explicitly disconnect, the TCP connection will be maintained.

  • Immature HTTP pipeline to solve the problem of queue blocking by pipeline technology.

  • Provide virtual host support, the Host field is added to the request header to indicate the current domain name address, so that the server can do different processing according to different Host values.

  • Provides perfect support for dynamically generated content, introducing chunk transfer mechanism. the server will divide the data into several data blocks of any size, each data block will be attached with the length of the last data block, and finally use a zero-length block as a sign of sending data

  • Client cookies security mechanism

Continue to share tomorrow, Hope it can help you :)

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