CRUD

一个由内存 store 支撑的完整 CRUD（create, read, update, delete）API。每个处理函数都会把 JSON 请求体绑定到 struct，在锁保护下修改 store，并以 JSON 返回结果。

服务器

package main

import (
  "context"
  "net/http"
  "strconv"
  "sync"

  "github.com/labstack/echo/v5"
  "github.com/labstack/echo/v5/middleware"
)

type (
  user struct {
    ID   int    `json:"id"`
    Name string `json:"name"`
  }
)

var (
  users = map[int]*user{}
  seq   = 1
  lock  = sync.Mutex{}
)

//----------
// Handlers
//----------

func createUser(c *echo.Context) error {
  lock.Lock()
  defer lock.Unlock()
  u := &user{
    ID: seq,
  }
  if err := c.Bind(u); err != nil {
    return err
  }
  users[u.ID] = u
  seq++
  return c.JSON(http.StatusCreated, u)
}

func getUser(c *echo.Context) error {
  lock.Lock()
  defer lock.Unlock()
  id, _ := strconv.Atoi(c.Param("id"))
  return c.JSON(http.StatusOK, users[id])
}

func updateUser(c *echo.Context) error {
  lock.Lock()
  defer lock.Unlock()
  u := new(user)
  if err := c.Bind(u); err != nil {
    return err
  }
  id, _ := strconv.Atoi(c.Param("id"))
  users[id].Name = u.Name
  return c.JSON(http.StatusOK, users[id])
}

func deleteUser(c *echo.Context) error {
  lock.Lock()
  defer lock.Unlock()
  id, _ := strconv.Atoi(c.Param("id"))
  delete(users, id)
  return c.NoContent(http.StatusNoContent)
}

func getAllUsers(c *echo.Context) error {
  lock.Lock()
  defer lock.Unlock()
  return c.JSON(http.StatusOK, users)
}

func main() {
  e := echo.New()

  // Middleware
  e.Use(middleware.RequestLogger())
  e.Use(middleware.Recover())

  // Routes
  e.GET("/users", getAllUsers)
  e.POST("/users", createUser)
  e.GET("/users/:id", getUser)
  e.PUT("/users/:id", updateUser)
  e.DELETE("/users/:id", deleteUser)

  // Start server
  sc := echo.StartConfig{Address: ":1323"}
  if err := sc.Start(context.Background(), e); err != nil {
    e.Logger.Error("failed to start server", "error", err)
  }
}

客户端

创建用户

请求：

curl -X POST \
  -H 'Content-Type: application/json' \
  -d '{"name":"Joe Smith"}' \
  localhost:1323/users

响应：

{
  "id": 1,
  "name": "Joe Smith"
}

获取用户

请求：

curl localhost:1323/users/1

响应：

{
  "id": 1,
  "name": "Joe Smith"
}

更新用户

请求：

curl -X PUT \
  -H 'Content-Type: application/json' \
  -d '{"name":"Joe"}' \
  localhost:1323/users/1

响应：

{
  "id": 1,
  "name": "Joe"
}

删除用户

请求：

curl -X DELETE localhost:1323/users/1

响应：204 No Content。