15. HTTP Servers

Activity 15.01: Adding a Page Counter to an HTML Page

Solution:

1. First, we import the necessary packages:

   package main
   import (
   "fmt"
   "log"
   "net/http"
   )

2. Here, "net/http" is the usual package for http communication, "log" is the package for logging (in this case to the standard output), and "fmt" is the package used to format input and output. This can be used to send messages to the standard output, but we use it here just as a message formatter.
3. We define here a type called PageWithCounter, which represents our handler, can count visits, and has a heading and some content for the page. The counter will increase every time the page loads:

   type PageWithCounter struct{
   counter int
   heading string
   content string
   }
   func(h *PageWithCounter) ServeHTTP(w http.ResponseWriter, r *http.Request)   {

   This is the standard handler function for any struct implementing the http.Handler interface. Note...