HTTP Message Structure

So, the client and the server exchange messages with each other, which are designed in a special way. Let's look at the structure of these messages.

Each HTTP message consists of three parts, which are transmitted in the specified order: the start line, the headers, and the message body.

Technically, the start line is the first line of the message, then each new line has one header, then a blank line, and then the body of the request.

The start line defines the message type, the headers characterize the message body, transmission parameters and other information, and the body contains the message data itself.

The start line and headers are mandatory elements, but the body is optional. However, the start lines are different for the request and response.

In the following lessons we will analyze each part of the HTTP message separately.