HTTP Message Flow and Message Parts - Part 1 of Chapter 3 from HTTP: The Definitive Guide (7/7)
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HTTP: The Definitive Guide, Chapter 3: HTTP Messages
Entity Bodies
The third part of an HTTP message is the optional entity body. Entity bodies are the payload of HTTP messages. They are the things that HTTP was designed to transport.
HTTP messages can carry many kinds of digital data: images, video, HTML documents, software applications, credit card transactions, electronic mail, and so on.
Version 0.9 Messages
HTTP Version 0.9 was an early version of the HTTP protocol. It was the starting point for the request and response messages that HTTP has today, but with a far simpler protocol (see Figure 3-6).
Figure 3-6. HTTP/0.9 transaction
HTTP/0.9 messages also consisted of requests and responses, but the request contained merely the method and the request URL, and the response contained only the entity. No version information (it was the first and only version at the time), no status code or reason phrase, and no headers were included.
However, this simplicity did not allow for much flexibility or the implementation of most of the HTTP features and applications described in this book. We briefly describe it here because there are still clients, servers, and other applications that use it, and application writers should be aware of its limitations.
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Created: January 13, 2003
Revised: January 13, 2003
URL: https://webreference.com/programming/http/chap3/1/7.html