Gin入門① スタートアップ ～ Go言語フレームワーク ～

事前準備

Ginとは

最大40倍速の高性能なパフォーマンスを誇る。

環境

Goの環境構築に関しては下記参照。

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2021.02.26

go modを使用してリポジトリを管理する。

$ go mod init <フォルダ名>
(例)　$ go mod init gin-start

go modの初期化が完了したらGinをインストールする。

$ go get -u github.com/gin-gonic/gin

使用アプリ

Talend API TesterはGoogle Chromeの拡張機能でインストールが容易なため使用。

開発

ディレクトリ構成

gin-started
├─go.mod
├─go.sum
├─main.go
├─controller
│ └─user_controller.go
├─model
│ └─user.go
└─service
  └─user_service.go

ソース

• main.go

package main

import (
	"gin-start/controller"
	"gin-start/service"

	"github.com/gin-gonic/gin"
)

var (
	userService    service.UserService       = service.New()
	userController controller.UserController = controller.New(userService)
)

func main() {

	router := gin.Default()

	router.GET("/user", func(ctx *gin.Context) {
		ctx.JSON(200, userController.FindAll())
	})

	router.POST("/user", func(ctx *gin.Context) {
		ctx.JSON(200, userController.Save(ctx))
	})

	router.Run("localhost:8080")

}

• model.go

package model

type Users struct {
	Id   int    `json:"id"`
	Name string `json:"name"`
}

• user_service.go

package service

import "gin-start/model"

type UserService interface {
	Save(model.Users) model.Users
	FindAll() []model.Users
}
type userService struct {
	users []model.Users
}

func New() UserService {
	return &userService{}
}

func (service *userService) Save(user model.Users) model.Users {
	service.users = append(service.users, user)
	return user
}

func (service *userService) FindAll() []model.Users {
	return service.users
}

• user_controller.go

package controller

import (
	"gin-start/model"
	"gin-start/service"

	"github.com/gin-gonic/gin"
)

type UserController interface {
	FindAll() []model.Users
	Save(ctx *gin.Context) model.Users
}

type controller struct {
	service service.UserService
}

func New(service service.UserService) UserController {
	return &controller{
		service: service,
	}
}

func (c *controller) FindAll() []model.Users {
	return c.service.FindAll()
}

func (c *controller) Save(ctx *gin.Context) model.Users {
	var user model.Users
	ctx.BindJSON(&user)
	c.service.Save(user)
	return user
}			

実行

プログラム実行

$ go run main.go

(結果)
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
	- using env:   export GIN_MODE=release
	- using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /user                     --> main.main.func1 (3 handlers)
[GIN-debug] POST   /user                     --> main.main.func2 (3 handlers)
[GIN-debug] [WARNING] You trusted all proxies, this is NOT safe. We recommend you to set a value.
Please check https://pkg.go.dev/github.com/gin-gonic/gin#readme-don-t-trust-all-proxies for details.
[GIN-debug] Listening and serving HTTP on localhost:8080

API実行

POST

GET

Log

[GIN] 2022/01/30 - 18:35:16 | 200 |      1.7439ms |       127.0.0.1 | POST     "/user"
[GIN] 2022/01/30 - 18:36:14 | 200 |            0s |       127.0.0.1 | GET      "/user"