使用 Go 實現 CURD 功能

$ go mod init gin-curd # 初始 go 專案模塊
$ go install github.com/cosmtrek/air@latest # 安裝監聽服務，類似 live reload 功能
$ go get -u github.com/gin-gonic/gin # 有名的 routing pkg
$ go get github.com/joho/godotenv # .env 環境變數 pkg
$ go get -u gorm.io/gorm # DB ORM
$ go get -u gorm.io/driver/mysql # mysql driver

package initializers

import (
	"log"
	"github.com/joho/godotenv"
)

func LoadEnvVariables() { // 確保大寫暴露使用接口
	err := godotenv.Load()
	if err != nil {
		log.Fatal("Error load .env file.")
	}
}

package initializers

import (
	"log"
	"os"

	"gorm.io/driver/mysql"
	"gorm.io/gorm"
)

var DB *gorm.DB

func Connection() {
	var err error
	dsn := os.Getenv("APP_CONNECTION") // 取得 .env 內的 APP_CONNECTION 變數
	DB, err = gorm.Open(mysql.Open(dsn), &gorm.Config{}) //參考 gorm 文件 https://gorm.io/docs/connecting_to_the_database.html#MySQL

	if err != nil {
		log.Fatal("Connection failed.")
	}
}

package models

import (
	"time"
	"gorm.io/plugin/soft_delete" // go mod tidy 抓 plugin pkg, 這邊我想自訂數據庫欄位順序
)

type Post struct {
	ID        uint `gorm:"primarykey"`
	Title string
	Body string
	CreatedAt time.Time
	UpdatedAt time.Time
	DeletedAt soft_delete.DeletedAt `gorm:"index"`
	// gorm.Model, 或是可以方便使用這個
}

package main

import (
	"go-curd/initializers"
	"go-curd/models"
)

func init() {
	initializers.LoadEnvVariables() //載入環境變數
	initializers.Connection() //建立連線
}

func main() {
	initializers.DB.AutoMigrate(&models.Post{}) //參考文件 https://gorm.io/docs/migration.html#Auto-Migration
}

$ go run migrations/migrate.go

package controllers

import (
	"errors"
	"go-curd/initializers"
	"go-curd/models"

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

func PostCreate(c *gin.Context) {
	var content struct { // 宣告接收傳入參數
		Title string
		Body string
	}
	c.Bind(&content)

	post := models.Post{Title: content.Title, Body: content.Body} // model 指定寫入
	result := initializers.DB.Create(&post) // 建立
	if result.Error != nil {
		c.Status(400)
		return
	}

	c.JSON(200, gin.H{
		"post": post,
	})
}

func PostIndex(c *gin.Context) {
	var posts []models.Post
	initializers.DB.Find(&posts)

	c.JSON(200, gin.H{
		"posts": posts,
	})
}

func PostShow(c *gin.Context) {
	id := c.Param("id") // 接收 uri 參數
	var post models.Post
	if err := initializers.DB.First(&post, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) { //如果錯誤訊息是 not found 則出現 post not found json 回應訊息
			c.JSON(404, gin.H{
				"error": "Post not found",
			})

			return
		}

		c.JSON(422, gin.H{
			"error": err,
		})
	}

	c.JSON(200, gin.H{
		"post": post,
	})
}

func PostUpdate(c *gin.Context) {
	id := c.Param("id")

	var content struct {
		Title string
		Body string
	}
	c.Bind(&content)

	var post models.Post
	if err := initializers.DB.First(&post, id).Error; err != nil { //取得 post
		if errors.Is(err, gorm.ErrRecordNotFound) {
			c.JSON(404, gin.H{
				"error": "Post not found",
			})

			return
		}

		c.JSON(422, gin.H{
			"error": err,
		})
	}

	initializers.DB.Model(&post).Updates(models.Post{ //更新 &post
		Title: content.Title,
		Body: content.Body,
	})

	c.JSON(200, gin.H{
		"post": post,
	})
}

func PostDestory(c *gin.Context) {
	id := c.Param("id")

	initializers.DB.Delete(&models.Post{}, id)

	c.Status(200)
}

package main

import (
	"go-curd/initializers"
	"go-curd/controllers"
	"github.com/gin-gonic/gin"
)

func init() {
	initializers.LoadEnvVariables()
	initializers.Connection()
}

func main() {
	r := gin.Default()
	r.POST("/posts", controllers.PostCreate)
	r.GET("/posts", controllers.PostIndex)
	r.GET("/posts/:id", controllers.PostShow)
	r.PUT("/posts/:id", controllers.PostUpdate)
	r.DELETE("/posts/:id", controllers.PostDestory)
	r.Run()
}

go run main.go
[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] POST   /posts                    --> go-curd/controllers.PostCreate (3 handlers)
[GIN-debug] GET    /posts                    --> go-curd/controllers.PostIndex (3 handlers)
[GIN-debug] GET    /posts/:id                --> go-curd/controllers.PostShow (3 handlers)
[GIN-debug] PUT    /posts/:id                --> go-curd/controllers.PostUpdate (3 handlers)
[GIN-debug] DELETE /posts/:id                --> go-curd/controllers.PostDestory (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] Environment variable PORT is undefined. Using port :8080 by default
[GIN-debug] Listening and serving HTTP on :8080