simple usage of Gorilla Mux in Go

server.go

package main

import (
	"encoding/json"
	"log"
	"net/http"
	"strconv"
	"time"

	"github.com/gorilla/mux"
)

// Note is a note
type Note struct {
	ID          int       `json:"id"`
	Title       string    `json:"title"`
	Description string    `json:"description"`
	CreatedOn   time.Time `json:"created_on"`
}

var noteStore = make(map[int]Note)

var id int

// PostNoteHandler creates a note
func PostNoteHandler(w http.ResponseWriter, r *http.Request) {
	var note Note
	err := json.NewDecoder(r.Body).Decode(&note)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(err.Error()))
		return
	}

	note.ID = id
	note.CreatedOn = time.Now()

	noteStore[id] = note

	id++

	j, err := json.Marshal(note)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}

	w.Header().Set("Content-Type", "application/json")

	w.WriteHeader(http.StatusCreated)
	w.Write(j)
}

// GetNotesHandler gets all notes
func GetNotesHandler(w http.ResponseWriter, r *http.Request) {
	notes := make([]Note, 0)

	for _, v := range noteStore {
		notes = append(notes, v)
	}

	w.Header().Set("Content-Type", "application/json")

	j, err := json.Marshal(notes)

	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		w.Write([]byte(err.Error()))
		return
	}

	w.WriteHeader(http.StatusOK)
	w.Write(j)
}

// GetNoteHandler gets a single note
func GetNoteHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	idStr := vars["id"]

	id, err := strconv.Atoi(idStr)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(err.Error()))
		return
	}

	if note, ok := noteStore[id]; ok {
		w.Header().Set("Content-Type", "application/json")

		serializedNote, err := json.Marshal(note)

		if err != nil {
			w.WriteHeader(http.StatusInternalServerError)
			w.Write([]byte(err.Error()))
			return
		}

		w.WriteHeader(http.StatusOK)
		w.Write(serializedNote)
	} else {
		w.Write([]byte("Not found"))
		w.WriteHeader(http.StatusNotFound)
		return
	}
}

func main() {
	note := Note{
		Title:       "test title",
		Description: "test description",
		CreatedOn:   time.Now(),
		ID:          id,
	}

	noteStore[0] = note

	id++

	r := mux.NewRouter().StrictSlash(false)

	r.HandleFunc("/api/notes", GetNotesHandler).Methods("GET")
	r.HandleFunc("/api/notes/", GetNotesHandler).Methods("GET")
	r.HandleFunc("/api/notes/{id}", GetNoteHandler).Methods("GET")
	r.HandleFunc("/api/notes", PostNoteHandler).Methods("POST")
	r.HandleFunc("/api/notes/", PostNoteHandler).Methods("POST")

	server := &http.Server{
		Addr:    ":8080",
		Handler: r,
	}

	log.Println(">> Listening on :8080")

	server.ListenAndServe()
}