test_router.go

package main

import (
	"errors"
	"log"
	"net/http"
)

//A simple and basic router
type Router struct {
	routes []Route
}

//Route holds the method, path and HandlerFunc
type Route struct {
	Method string
	Path   string
	Handle http.HandlerFunc
}

func main() {

	r := New()

	r.GET("/", hello)
	r.POST("/users", users)

	r.GET("/hello", hello)
	http.ListenAndServe(":8080", r)

}

//New instanciate a new Router
func New() *Router {
	var router Router

	return &router
}

//POST accepts and append handler, path, method to Router rouet slice
func (rt *Router) POST(path string, handle http.HandlerFunc) {
	route := Route{}
	route.Method = "POST"
	route.Path = path
	route.Handle = handle

	rt.routes = append(rt.routes, route)
}

//GET for a get request
func (rt *Router) GET(path string, handle http.HandlerFunc) {
	route := Route{}
	route.Method = "GET"
	route.Path = path
	route.Handle = handle

	rt.routes = append(rt.routes, route)
}

//ServeHTTP runs the server
func (rt *Router) ServeHTTP(w http.ResponseWriter, r *http.Request) {

	path := r.URL.Path
	route, err := rt.checkRoute(r.Method, path)

	log.Printf("path %v", r.URL.Path)

	if err != nil {
		log.Printf("%v", err)
		http.NotFound(w, r)
		return
	}

	route.Handle(w, r)
	return

}

func (rt *Router) checkRoute(method string, path string) (*Route, error) {
	for _, route := range rt.routes {

		// log.Printf("%v", k)
		if route.Method == method && route.Path == path {
			return &route, nil
		}

	}

	return &Route{}, errors.New("Not found")
}

func users(w http.ResponseWriter, r *http.Request) {
	users := `{"username": "John Doe"}`

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(200)
	w.Write([]byte(users))
}

func hello(w http.ResponseWriter, r *http.Request) {
	users := `{"welcome": "home"}`

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(200)
	w.Write([]byte(users))
}