main.go

package main

import (
	"encoding/json"
	"math/rand"
	"net/http"
	"strconv"

	"github.com/gorilla/mux"
)

type Book struct {
	ID     string  `json:"id"`
	Isbn   string  `json:"isbn"`
	Title  string  `json:"title"`
	Author *Author `json:"author"`
}

type Author struct {
	Firstname string `json:"firstname"`
	Lastname  string `json:"lastname"`
}

var books []Book

func getBooks(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-type", "application/json")
	json.NewEncoder(w).Encode(books)
}
func getBook(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "applcation/json")
	params := mux.Vars(r)

	for _, item := range books {
		if item.ID == params["id"] {
			json.NewEncoder(w).Encode(item)
			return
		}
	}
	json.NewEncoder(w).Encode(&Book{})
}

func createBook(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	var book Book
	_ = json.NewDecoder(r.Body).Decode(&book)
	book.ID = strconv.Itoa(rand.Intn(1000000))
	books = append(books, book)
	json.NewEncoder(w).Encode(book)

}
func deleteBook(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	params := mux.Vars(r)
	for index, item := range books {
		if item.ID == params["id"] {
			books = append(books[:index], books[index+1:]...)
			break
		}
	}
	json.NewEncoder(w).Encode(books)
}

func main() {

	r := mux.NewRouter()

	// books = append(books, Book{ID: "1", Isbn: "2342", Title: "the hate story", Author: &Author{Firstname: "kunal", Lastname: "Kumar"}})
	// books = append(books, Book{ID: "2", Isbn: "6775", Title: "the hate story 2", Author: &Author{Firstname: "kunal kusma", Lastname: "Kumar"}})

	r.HandleFunc("/api/book", getBooks).Methods("GET")
	r.HandleFunc("/api/book/{id}", getBook).Methods("GET")
	r.HandleFunc("/api/book", createBook).Methods("POST")
	r.HandleFunc("/api/book/{id}", deleteBook).Methods("DELETE")

	http.ListenAndServe(":8002", r)

}