main.go.bk

package main

import (
  "encoding/json"
  "github.com/gorilla/mux"
  "log"
  "math/rand"
  "net/http"
  "strconv"
  "fmt"
)

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

type Author struct {
  FirstName	string `json:"firstname"`
  LastName	string	`json:"lastname"`
}

// Bookのデータを保持するスライスの作成
var books []Book

// Get All Books
func getBooks(w http.ResponseWriter, r *http.Request) {
  w.Header().Set("Content-Type", "application/json")
  fmt.Println(json.NewEncoder(w))
  json.NewEncoder(w).Encode(books)
}

// Get Single Book
func getBook(w http.ResponseWriter, r *http.Request) {
  w.Header().Set("Content-Type", "application/json")
  params := mux.Vars(r)

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

// Create a 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(10000)) // Mock ID - not safe in production
  books = append(books, book)
  json.NewEncoder(w).Encode(book)
}

// Update a Book
func updateBook(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:]...)
      var book Book
      _ = json.NewDecoder(r.Body).Decode(&book)
      book.ID = params["id"]
      books = append(books, book)
      json.NewEncoder(w).Encode(book)
      return
    }
  }
  json.NewEncoder(w).Encode(books)
}

// Delete a 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() {
  // ルーターのイニシャライズ
  r := mux.NewRouter()

  // モックデータ作成
  books = append(books, Book{ID: "1", Title: "Book one", Author: &Author{FirstName: "tanjiro", LastName: "kamado"}})
  books = append(books, Book{ID: "2", Title: "Book two", Author: &Author{FirstName: "John", LastName: "Johnson"}})

  fmt.Println(books)

  // エンドポイント
  r.HandleFunc("/api/books", getBooks).Methods("GET")
  r.HandleFunc("/api/books/{id}", getBook).Methods("GET")
  r.HandleFunc("/api/books", createBook).Methods("POST")
  r.HandleFunc("/api/books/{id}", updateBook).Methods("PUT")
  r.HandleFunc("/api/books/{id}", deleteBook).Methods("DELETE")

  // http.ServeMuxがデフォルトだが今回はルータを渡している
  log.Fatal(http.ListenAndServe(":8000", r))
}