18_routing

init

Add a package level scope variable

var db *sql.DB

Initialize your database

Note: defer.db.Close() has been removed

func init() {
	var err error
	db, err = sql.Open("postgres", "postgres://bond:password@localhost/bookstore?sslmode=disable")
	if err != nil {
		panic(err)
	}

	if err = db.Ping(); err != nil {
		panic(err)
	}
	fmt.Println("You connected to your database.")
}

add routes & server

func main() {
	http.HandleFunc("/", index)
	http.ListenAndServe(":8080", nil)
}

add a index func

func index(w http.ResponseWriter, r *http.Request){
	if r.Method != "GET" {
		http.Error(w, http.StatusText(405), http.StatusMethodNotAllowed)
		return
	}

	rows, err := db.Query("SELECT * FROM books")
	if err != nil {
		http.Error(w, http.StatusText(500), 500)
		return
	}
	defer rows.Close()

	bks := make([]Book, 0)
	for rows.Next() {
		bk := Book{}
		err := rows.Scan(&bk.isbn, &bk.title, &bk.author, &bk.price) // order matters
		if err != nil {
			http.Error(w, http.StatusText(500), 500)
			return
		}
		bks = append(bks, bk)
	}
	if err = rows.Err(); err != nil {
		http.Error(w, http.StatusText(500), 500)
		return
	}

	for _, bk := range bks {
		fmt.Fprintf(w, "%s, %s, %s, $%.2f\n", bk.isbn, bk.title, bk.author, bk.price)
	}
}

run the application and make a request

curl -i localhost:8080/books