Chapter 1. Overview of HTTP

The world's web browsers, servers, and related web applications all talk to each other through HTTP, the Hypertext Transfer Protocol. HTTP is the common language of the modern global Internet.

This chapter is a concise overview of HTTP. You'll see how web applications use HTTP to communicate, and you'll get a rough idea of how HTTP does its job. In particular, we talk about:

How web clients and servers communicate

Where resources (web content) come from

How web transactions work

The format of the messages used for HTTP communication

The underlying TCP network transport

The different variations of the HTTP protocol

Some of the many HTTP architectural components installed around the Internet

We've got a lot of ground to cover, so let's get started on our tour of HTTP.