Chapter 4. Processing requests

In the previous chapter we explored serving web applications with the built-in net/http library. You also learned about handlers, handler functions, and multiplexers. Now that you know about receiving and handing off the request to the correct set of functions, in this chapter we’ll investigate the tools that Go provides to programmers to process requests and send responses back to the client.

4.1. Requests and responses

In chapter 1 we went through quite a bit of information about HTTP messages. If that chapter was a blur to you, now would be a great time to revisit it. HTTP messages are messages sent between the client and the server. There are two types of HTTP messages: HTTP request and HTTP response.

Both requests and responses have basically the same structure:

1.  Request or response line

2.  Zero or more headers

3.  An empty line, followed by ...

4.  ... an optional message body

Here’s an example of a GET request:

The net/http library provides structures for HTTP messages, and you need to know these structures to understand how to process requests and send responses. Let’s start with the request.

4.1.1. Request

4.2. HTML forms and Go

4.3. ResponseWriter

4.4. Cookies

4.5. Summary