main.go

package main

import (
	"fmt"
	"net/http"
)

func speakHandler(w http.ResponseWriter, req *http.Request) {
	switch req.Method {
	case "GET":
		fmt.Fprintf(w, "Hello World!")
	case "POST":
		fmt.Fprintf(w, "Thank You!")
	case "DELETE":
		fmt.Fprintf(w, "Goodbye, World!")
	default:
		panic("Unrecognized method")
	}
}

func mainMux() *http.ServeMux {
	mux := http.NewServeMux()
	mux.HandleFunc("/speak", speakHandler)
	return mux
}

func main() {
	http.ListenAndServe(":3000", mainMux())
}