main.go

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"

	"github.com/gorilla/mux"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
)

type Star struct {
	ID          uint   `json:"id"`
	Name        string `gorm:"unique" json:"name"`
	Description string `json:"description"`
	URL         string `json:"url"`
}

type App struct {
	DB *gorm.DB
}

func (a *App) Initialize(dbDriver string, dbURI string) {
	db, err := gorm.Open(dbDriver, dbURI)
	if err != nil {
		panic("failed to connect database")
	}
	a.DB = db

	// Migrate the schema.
	a.DB.AutoMigrate(&Star{})
}

func (a *App) ListHandler(w http.ResponseWriter, r *http.Request) {
	var stars []Star

	// Select all stars and convert to JSON.
	a.DB.Find(&stars)
	starsJSON, _ := json.Marshal(stars)

	// Write to HTTP response.
	w.WriteHeader(200)
	w.Write([]byte(starsJSON))
}

func (a *App) ViewHandler(w http.ResponseWriter, r *http.Request) {
	var star Star
	vars := mux.Vars(r)

	// Select the star with the given name, and convert to JSON.
	a.DB.First(&star, "name = ?", vars["name"])
	starJSON, _ := json.Marshal(star)

	// Write to HTTP response.
	w.WriteHeader(200)
	w.Write([]byte(starJSON))
}

func (a *App) CreateHandler(w http.ResponseWriter, r *http.Request) {
	// Parse the POST body to populate r.PostForm.
	if err := r.ParseForm(); err != nil {
		panic("failed in ParseForm() call")
	}

	// Create a new star from the request body.
	star := &Star{
		Name:        r.PostFormValue("name"),
		Description: r.PostFormValue("description"),
		URL:         r.PostFormValue("url"),
	}
	a.DB.Create(star)

	// Form the URL of the newly created star.
	u, err := url.Parse(fmt.Sprintf("/stars/%s", star.Name))
	if err != nil {
		panic("failed to form new Star URL")
	}
	base, err := url.Parse(r.URL.String())
	if err != nil {
		panic("failed to parse request URL")
	}

	// Write to HTTP response.
	w.Header().Set("Location", base.ResolveReference(u).String())
	w.WriteHeader(201)
}

func (a *App) UpdateHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)

	// Parse the POST body to populate r.PostForm.
	if err := r.ParseForm(); err != nil {
		panic("failed in ParseForm() call")
	}

	// Set new star values from the request body.
	star := &Star{
		Name:        r.PostFormValue("name"),
		Description: r.PostFormValue("description"),
		URL:         r.PostFormValue("url"),
	}

	// Update the star with the given name.
	a.DB.Model(&star).Where("name = ?", vars["name"]).Updates(&star)

	// Write to HTTP response.
	w.WriteHeader(204)
}

func (a *App) DeleteHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)

	// Delete the star with the given name.
	a.DB.Where("name = ?", vars["name"]).Delete(Star{})

	// Write to HTTP response.
	w.WriteHeader(204)
}

func main() {
	a := &App{}
	a.Initialize("sqlite3", "test.db")

	r := mux.NewRouter()

	r.HandleFunc("/stars", a.ListHandler).Methods("GET")
	r.HandleFunc("/stars/{name:.+}", a.ViewHandler).Methods("GET")
	r.HandleFunc("/stars", a.CreateHandler).Methods("POST")
	r.HandleFunc("/stars/{name:.+}", a.UpdateHandler).Methods("PUT")
	r.HandleFunc("/stars/{name:.+}", a.DeleteHandler).Methods("DELETE")
	r.PathPrefix("/").Handler(http.FileServer(http.Dir("./build/"))).Methods("GET")

	http.Handle("/", r)
	if err := http.ListenAndServe(":8080", nil); err != nil {
		panic(err)
	}

	defer a.DB.Close()
}