golang REST API / go언어 REST API 서버 #5 METHOD GET item

POST /device       -> Device 아이템 추가 (포스팅 완료)  / curl -X POST -H "Content-Type: application/json" -d '{"name":"iPhone19","mac":"ff:11:11:22:33:11"}' http://localhost:8000/v1.0/device
GET /device        -> Device 아이템 리스트 조회 (포스팅 완료) / curl -X GET -H "Content-Type: application/json" -d '{}' http://localhost:8000/v1.0/device
GET /device/{pk}   -> Device 아이템 조회 (진행중) /  curl -X GET -H "Content-Type: application/json" -d '{}' http://localhost:8000/v1.0/device/1
PUT /device/{pk}    -> Device 아이템 수정
DELETE /device/{pk} -> Device 아이템 삭제

이어서 GET 1개 아이템 GET 응답을 포스팅하려 합니다.
순수하게 공부 차원에서 "net/http"만 사용해서 하려 했는데, HandleFunc에서 패턴 라우팅을 구현하기에는 지금은 난감합니다.
나중에 golang 웹프레이워크 깃헙에 들어가서 어떻게 구현했는지 공부좀해야겠습니다.
결국 많이 쓰이는 것 몇 중에 mux로 구현하겠습니다.



처음부터 프레임워크로 시작했어야 하는데 공부 차원에서 "net/http" 시작했다가 소스가 지저분해지는데 마지막에 mux로 리팩토링해야겠습니다.
역시 코드를 짜면 짤수록 django의 위대함을 느낍니다. 개인적으로 웹 프레임워크는 인터프린터 언어가 유연한 거 같습니다.

호출한 결과입니다. MAC출력도 해야하는데 늦은 시간이라 다음번에 수정 하겠습니다.

 

 

package main

import (
   "database/sql"
   "encoding/json"
   "fmt"
   "net/http"
   "strings"

   _ "github.com/go-sql-driver/mysql"
   "github.com/gorilla/mux"
)

type Device struct {
   Id   int    `json:"id"`
   Name string `json:"name"`
   Mac  string `json:"mac"`
}

const (
   httpPort       = ":8000"
   driverName     = "mysql"
   dataSourceName = "TheGolangOfFuture:TheGolangOfFuture@tcp(127.0.0.1:3306)/TheGolangOfFuture"
)

func device(res http.ResponseWriter, req *http.Request) {
   db, err := sql.Open(driverName, dataSourceName)
   if err != nil {
      fmt.Printf(err.Error())
      res.WriteHeader(http.StatusInternalServerError)
      return
   }
   defer db.Close()

   if req.Method == http.MethodPost {
      var device Device
      err := json.NewDecoder(req.Body).Decode(&device)
      if err != nil {
         res.WriteHeader(http.StatusBadRequest)
         return
      }

      fmt.Printf("[POST] Name=%s,Mac=%s\n", device.Name, device.Mac) // DB insert

      tmpMac := strings.Replace(device.Mac, ":", "", -1) // 맥은 ":", "-", "." 등 여러가지가 올 수 있지만 예제에서는 ":"만 처리 하겠습니다.

      query := fmt.Sprintf("INSERT INTO Device (name, mac, mac_bin) VALUES('%s', '%s', unhex('%s'))", device.Name, device.Mac, tmpMac) // 이코드는 사실상 너무나 취약합니다.
      insert, err := db.Query(query)
      if err != nil {
         fmt.Println(err.Error())
         res.WriteHeader(http.StatusInternalServerError)
         return
      }
      defer insert.Close()

      res.Header().Set("Content-Type", "application/json")
      res.WriteHeader(http.StatusOK)
      json.NewEncoder(res).Encode(map[string]interface{}{
         "success":  true,
         "messages": fmt.Sprintf("Post success : %s", device.Mac),
      })
   } else if req.Method == http.MethodGet {
      vars := mux.Vars(req)
      if id, ok := vars["id"]; ok == true {

         rs, err := db.Query(fmt.Sprintf("SELECT id, name FROM Device where id = %s", id))
         if err != nil {
            fmt.Println(err.Error())
            res.WriteHeader(http.StatusInternalServerError)
            return
         }
         defer rs.Close()

         for rs.Next() {
            var d Device
            err := rs.Scan(&d.Id, &d.Name)
            if err != nil {
               fmt.Println(err.Error())
               res.WriteHeader(http.StatusInternalServerError)
               return
            }
            json.NewEncoder(res).Encode(map[string]interface{}{
               "success": true,
               "data":    d,
            })
         }

      } else {

         rs, err := db.Query("SELECT id, name FROM Device")
         if err != nil {
            fmt.Println(err.Error())
            res.WriteHeader(http.StatusInternalServerError)
            return
         }
         defer rs.Close()

         var result []Device
         for rs.Next() {
            var d Device
            err := rs.Scan(&d.Id, &d.Name)
            if err != nil {
               fmt.Println(err.Error())
               res.WriteHeader(http.StatusInternalServerError)
               return
            }
            result = append(result, d)
         }

         json.NewEncoder(res).Encode(map[string]interface{}{
            "success": true,
            "data":    result,
         })
      }
      res.Header().Set("Content-Type", "application/json")
      res.WriteHeader(http.StatusOK)

   } else {
      res.WriteHeader(http.StatusMethodNotAllowed) // 나머지 메소드는 허용안함
   }

}

func main() {
   fmt.Println("Start WEB", httpPort)
   m := mux.NewRouter()
   m.HandleFunc("/v1.0/device/{id:[0-9]+}", device).Methods("GET")

   http.HandleFunc("/v1.0/device", device)
   http.Handle("/", m)
   http.ListenAndServe(httpPort, nil)
}