Once we run the program, the HTTP server will start locally listening on port 8080, and accessing http://localhost:8080/, http://localhost:8080/post, and http://localhost:8080/hello/foo from a browser or command line will produce the message defined in the corresponding handler definition. For example, execute http://localhost:8080/ from the command line, as follows:

$ curl -X GET -i http://localhost:8080/

This will give us the following response from the server:

We could also execute http://localhost:8080/hello/foo from the command line, as follows:

$ curl -X GET -i http://localhost:8080/hello/foo

This will give us the following response from the server:

var GetRequestHandler = http.HandlerFunc
(
  func(w http.ResponseWriter, r *http.Request) 
  {
    w.Write([]byte("Hello World!"))
  }
)
var PostRequestHandler = http.HandlerFunc
(
  func(w http.ResponseWriter, r *http.Request) 
  {
    w.Write([]byte("It's a Post Request!"))
  }
)

2. Next, we defined PathVariableHandler, which extracts request path variables, gets the value, and writes it to an HTTP response stream, as follows:

var PathVariableHandler = http.HandlerFunc
(
  func(w http.ResponseWriter, r *http.Request) 
  {
    vars := mux.Vars(r)
    name := vars["name"]
    w.Write([]byte("Hi " + name))
  }
)

3. Then, we registered all these handlers with the gorilla/mux router and instantiated it, calling the NewRouter() handler of the mux router, as follows:

func main() 
{
  router := mux.NewRouter()
  router.Handle("/", GetRequestHandler).Methods("GET")
  router.Handle("/post", PostCallHandler).Methods("POST")
  router.Handle("/hello/{name}", PathVariableHandler).
  Methods("GET", "PUT")
  http.ListenAndServe(CONN_HOST+":"+CONN_PORT, router)
}