Golangで簡単掲示板作成
はじめに
go、mysqlのversion確認
$ go version
go version go1.7.1 darwin/amd64
$ mysql --version
mysql Ver 14.14 Distrib 5.7.15, for osx10.11 (x86_64) using EditLine wrapper
環境変数を設定する
1) golangチュートリアルで設定した.zshvrの$GOPATHをコメントアウト
-export GOPATH=~/.go
+#export GOPATH=~/.go
2) .bash_profileに以下を追加
#golang
export GOROOT=/usr/local/opt/go/libexec
export GOPATH=$HOME/.go
export PATH=$PATH:$GOROOT/bin:$GOPATH/bin
revel を install する
$ go get github.com/revel/revel
$ go get github.com/revel/cmd/revel
インストールされたrevelを確認
$ revel version
~
~ revel! http://revel.github.io
~
Version(s):
Revel v0.13.1 (2016-06-06)
go1.7.1 darwin/amd64
revel new app_nameでプロジェクトを作成する
shiro16さんのgolang-bbsを拝借
$ revel new github.com/shiro16/golang-bbs
~
~ revel! http://revel.github.io
~
Your application is ready:
/Users/xxxxxx/.go/src/github.com/shiro16/golang-bbs
You can run it with:
revel run github.com/shiro16/golang-bbs
revel runコマンドでwebサーバを起動する
$ revel run github.com/shiro16/golang-bbs
~
~ revel! http://revel.github.io
~
INFO 2016/10/07 14:28:23 revel.go:365: Loaded module testrunner
INFO 2016/10/07 14:28:23 revel.go:365: Loaded module static
INFO 2016/10/07 14:28:23 revel.go:230: Initialized Revel v0.13.1 (2016-06-06) for >= go1.4
INFO 2016/10/07 14:28:23 run.go:57: Running golang-bbs (github.com/shiro16/golang-bbs) in dev mode
INFO 2016/10/07 14:28:23 harness.go:170: Listening on :9000
INFO 2016/10/07 14:28:30 build.go:179: Cleaning dir tmp
INFO 2016/10/07 14:28:30 build.go:179: Cleaning dir routes
INFO 2016/10/07 14:28:30 build.go:179: Cleaning dir tmp
INFO 2016/10/07 14:28:30 build.go:179: Cleaning dir routes
INFO 2016/10/07 14:28:31 revel.go:365: Loaded module static
INFO 2016/10/07 14:28:31 revel.go:365: Loaded module testrunner
INFO 2016/10/07 14:28:31 revel.go:230: Initialized Revel v0.13.1 (2016-06-06) for >= go1.4
INFO 2016/10/07 14:28:31 main.go:30: Running revel server
Go to /@tests to run the tests.
Ctrl+Cでサーバ停止
API作成
routesファイルを編集
GET / App.Index
+ GET /api/v1/comments ApiV1Comments.Index
+ GET /api/v1/comments/:id ApiV1Comments.Show
+ POST /api/v1/comments ApiV1Comments.Create
+ DELETE /api/v1/comments/:id ApiV1Comments.Delete
controller作成
共通controllerを作成
// app/controllers/api/v1/v1.go
package controllers
import (
"github.com/revel/revel"
"github.com/shiro16/golang-bbs/app/utils"
"net/http"
)
// 埋め込みによって revel.Controller をラップした ApiV1Controller を定義する
type ApiV1Controller struct {
*revel.Controller
}
// エラーの際に返す Json 用の構造体
type ErrorResponse struct {
Code int `json:"code"`
Message string `json:"message"`
}
// 正常な際に返す Json 用の構造体(今回は1種類で統一する)
type Response struct {
Results interface{} `json:"results"`
}
// 引数として渡されて interface にリクエストの Json の値を格納する
func (c *ApiV1Controller) BindParams(s interface{}) error {
return utils.JsonDecode(c.Request.Body, s)
}
// Bad Request Error を返すやつ
func (c *ApiV1Controller) HandleBadRequestError(s string) revel.Result {
c.Response.Status = http.StatusBadRequest
r := ErrorResponse{c.Response.Status, s}
return c.RenderJson(r)
}
// Not Found Error を返すやつ
func (c *ApiV1Controller) HandleNotFoundError(s string) revel.Result {
c.Response.Status = http.StatusNotFound
r := ErrorResponse{c.Response.Status, s}
return c.RenderJson(r)
}
// Internal Server Error を返すやつ
func (c *ApiV1Controller) HandleInternalServerError(s string) revel.Result {
c.Response.Status = http.StatusInternalServerError
r := ErrorResponse{c.Response.Status, s}
return c.RenderJson(r)
}
comments controllerを作成
// app/controllers/api/v1/comments.go
package controllers
import (
"github.com/revel/revel"
"github.com/shiro16/golang-bbs/app/controllers"
)
type ApiV1Comments struct {
ApiV1Controller
}
func (c ApiV1Comments) Index() revel.Result {
r := Response{"index"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Show(id int) revel.Result {
r := Response{"show"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Create() revel.Result {
r := Response{"create"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Delete(id int) revel.Result {
r := Response{"delete"}
return c.RenderJson(r)
}
APIの動作確認
サーバを起動する
$ revel run github.com/shiro16/golang-bbs
別terminalを立ち上げてcurlコマンドを試す
$ curl http://localhost:9000/api/v1/comments
{
"results": "index"
}
$ curl http://localhost:9000/api/v1/comments/1
{
"results": "show"
}
$ curl -X POST http://localhost:9000/api/v1/comments
{
"results": "create"
}
$ curl -X DELETE http://localhost:9000/api/v1/comments/1
{
"results": "delete"
}
サーバを起動したterminalにコンソールログが表示された
2016/10/07 15:31:00.070 ::1 200 4.097022ms GET /api/v1/comments
2016/10/07 15:31:26.809 ::1 200 146.966µs GET /api/v1/comments/1
2016/10/07 15:31:39.625 ::1 200 108.271µs POST /api/v1/comments
2016/10/07 15:31:50.521 ::1 200 105.353µs DELETE /api/v1/comments/1
DB周り
- 使用するORM: github.com/jinzhu/gorm
- 使用するvalidation: github.com/go-validator/validator
DB の接続情報を追加
$ vi conf/app.conf
[dev]セクションに一行追加
+ db.info = "root@/golang_bbs_development?charset=utf8&parseTime=True
modelを作成
使用するORM(gorm)と使用するvalidation(validator)をインストールする
$ go get github.com/jinzhu/gorm
$ go get gopkg.in/validator.v2
comments modelを作成
// app/models/comment.go
package models
import (
"time"
)
type Comment struct {
ID uint64 `gorm:"primary_key" json:"id"`
Nickname string `sql:"size:64" json:"nickname" validate:"max=64"`
Body string `sql:"size:255" json:"body" validate:"min=1,max=255"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
DeletedAt *time.Time `json:"deleted_at"`
}
gorm controllerを作成
// app/controllers/gorm.go
package controllers
import (
_ "github.com/go-sql-driver/mysql"
"github.com/jinzhu/gorm"
"github.com/revel/revel"
"github.com/shiro16/golang-bbs/app/models"
"log"
)
var DB *gorm.DB
func InitDB() {
db, err := gorm.Open("mysql", dbInfoString())
if err != nil {
log.Panicf("Failed to connect to database: %v\n", err)
}
db.DB()
db.AutoMigrate(&models.Comment{}) # ここで table の作成を行っている
DB = &db
}
func dbInfoString() string {
s, b := revel.Config.String("db.info")
if !b {
log.Panicf("database info not found")
}
return s
}
上記のcontrollerを呼び出す処理を追記する
$ vi app/init.go
- import "github.com/revel/revel"
+ import(
+ "github.com/revel/revel"
+ "github.com/shiro16/golang-bbs/app/controllers"
+ )
func init() {
....
+ revel.OnAppStart(controllers.InitDB) // 28行目くらいに
}
controller で model を使用する
comments controller を編集
package controllers
import (
"github.com/revel/revel"
+ "github.com/shiro16/golang-bbs/app/controllers"
+ "github.com/shiro16/golang-bbs/app/models"
+ "gopkg.in/validator.v2"
)
type ApiV1Comments struct {
ApiV1Controller
}
func (c ApiV1Comments) Index() revel.Result {
+ comments := []models.Comment{}
+ if err := controllers.DB.Order("id desc").Find(&comments).Error; err != nil {
+ return c.HandleInternalServerError("Record Find Failure")
+ }
+ r := Response{comments}
- r := Response{"index"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Show(id int) revel.Result {
+ comment := &models.Comment{}
+ if err := controllers.DB.First(&comment, id).Error; err != nil {
+ return c.HandleNotFoundError(err.Error())
+ }
+ r := Response{comment}
- r := Response{"show"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Create() revel.Result {
+ comment := &models.Comment{}
+ if err := c.BindParams(comment); err != nil {
+ return c.HandleBadRequestError(err.Error())
+ }
+ if err := validator.Validate(comment); err != nil {
+ return c.HandleBadRequestError(err.Error())
+ }
+ if err := controllers.DB.Create(comment).Error; err != nil {
+ return c.HandleInternalServerError("Record Create Failure")
+ }
+ r := Response{comment}
- r := Response{"create"}
return c.RenderJson(r)
}
func (c ApiV1Comments) Delete(id int) revel.Result {
+ comment := models.Comment{}
+ if err := controllers.DB.First(&comment, id).Error; err != nil {
+ return c.HandleNotFoundError(err.Error())
+ }
+ if err := controllers.DB.Delete(&comment).Error; err != nil {
+ return c.HandleInternalServerError("Record Delete Failure")
+ }
+ r := Response{"success"}
- r := Response{"delete"}
return c.RenderJson(r)
}
APIの動作確認
サーバを起動する
$ revel run github.com/shiro16/golang-bbs
別terminalを立ち上げてcurlコマンドを試す→エラーになった！
$ curl -H "Content-type: application/json" -X POST -d '{"nickname":"shiro16", "body":"test comment"}' http://localhost:9000/api/v1/comments
Go Compilation Error
The Go code src/github.com/shiro16/golang-bbs/app/controllers/gorm.go does not compile: cannot use &db (type **gorm.DB) as type *gorm.DB in assignment
In src/github.com/shiro16/golang-bbs/app/controllers/gorm.go (around line 22)
17:
log.Panicf("Failed to connect to database: %v\n", err)
18:
}
19:
20:
db.DB()
21:
db.AutoMigrate(&models.Comment{})
22:
DB = &db
23:
}
24:
25:
func dbInfoString() string {
26:
s, b := revel.Config.String("db.info")
エラー解析中
続きは来週…
Written on October 7, 2016