Hello world

If you don't have Golang installed please Follow the instructions here

Now let's start our journey by just saying Hello world

package main

import (
	"net/http"
)

func main() {
	http.HandleFunc("/", handler)
	err := http.ListenAndServe("127.0.0.1:8080", nil)
	if err != nil {
		panic(err)
	}
}

func handler(w http.ResponseWriter, r *http.Request) {
	w.Write([]byte("Hello world"))
}

Run it

All the book examples can be run if you clone the book repo. go to the goexamples directory and run them using go run ./example-name

start the HTTP server:

cd goexamples
go run ./example-helloworld

Try it:

For testing the web server we are going to use curl

Open another terminal

curl -i http://localhost:8080

What's happenning here

With only 17 lines of code Go:

1. Starts a webserver that is listening on port 8080
2. When an HTTP request is made it executes the handler function

Next Steps

In the next section we are going to explain in more detail what is happening. We are going to exampine the net/http and in particular we are going to focus on http.Server, http.Request, http.ResponseWriter, http.ServeMux.