golang-gin框架使用1

一、处理请求，响应

\

包含不同请求类型的处理，response返回类型，类型绑定，和html模板和静态文件处理。

 

main.go

package main

import (
	"fmt"
	"log"
	"net/http"

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

func main() {
	engine := gin.Default()
	// curl -L 'http://localhost:8080/ping?name=xwp'
	engine.GET("/ping", func(c *gin.Context) {
		// c.Writer.Write([]byte("Hello, gin!\n"))
		query_res := c.DefaultQuery("name", "unknow")

		fmt.Printf("query_res: %v\n", query_res)
		c.JSON(http.StatusOK, gin.H{
			"message":  "pong",
			"fullPath": c.FullPath(),
		})
	})
	// curl -L --header 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'usern=xwp' --data-urlencode 'password=xwp123' http://localhost:8080/login
	engine.POST("/login", func(c *gin.Context) {
		var user, password string
		user, b := c.GetPostForm("user")
		if !b {
			c.Writer.Write([]byte("username is empty, please try again!\n"))
			return
		}
		password = c.PostForm("password")
		fmt.Printf("username: %v password: %v\n", user, password)
		c.Writer.Write([]byte(fmt.Sprintf("%v login successfully!", user)))
	})
	// curl -L --request DELETE 'http://localhost:8080/user/3'
	engine.DELETE("/user/:id", func(c *gin.Context) {
		id := c.Param("id")
		fmt.Printf("User id: %v\n", id)
		c.JSON(http.StatusOK, gin.H{
			"message": fmt.Sprintf("user %v has been deleted", id),
		})
	})
	// GET提交表单：curl -L 'http://localhost:8080/hello?id=27&username=xwp'
	engine.GET("/hello", func(c *gin.Context) {
		var s Student
		if err := c.ShouldBindQuery(&s); err != nil {
			log.Fatal(err)
			return
		}
		fmt.Printf("Id: %v\n", s.Id)
		fmt.Printf("Username: %v\n", s.Username)
		c.Writer.Write([]byte(fmt.Sprintf("hello %v\n", s.Username)))
	})
	// POST提交表单: curl -L 'http://localhost:8080/register' --header 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'name=xwp' --data-urlencode 'password=xwp123' --data-urlencode 'phone=8772463'
	engine.POST("/register", func(c *gin.Context) {
		var register Register
		if err := c.ShouldBind(&register); err != nil {
			log.Fatal(err)
			return
		}
		fmt.Printf("Name: %v\n", register.Name)
		fmt.Printf("Password: %v\n", register.Password)
		fmt.Printf("Phone: %v\n", register.Phone)
		c.Writer.Write([]byte(register.Name + " registe successfully!"))
	})
	// POST提交json数据表单: curl -L 'http://localhost:8080/addstudent' --header 'Content-Type: application/json' --data '{"id": 100,"username": "yjj"}'
	engine.POST("/addstudent", func(c *gin.Context) {
		var student Student
		if err := c.BindJSON(&student); err != nil {
			log.Fatal(err)
			return
		}
		fmt.Printf("student.Id: %v\n", student.Id)
		c.Writer.Write([]byte(fmt.Sprintf("%v add successfully!\n", student.Username)))
	})
	// resopnse以json格式返回一个结构体对象  curl -L http://localhost:8080/jsonstruct
	engine.GET("/jsonstruct", func(c *gin.Context) {
		stu1 := Student{Id: 5378, Username: "Lenyu"}
		c.JSON(http.StatusOK, &stu1)
	})
	// 返回一个html  curl -L http://localhost:8080/testhtml
	engine.LoadHTMLGlob("./html/*")
	engine.Static("static", "static")
	engine.GET("testhtml", func(c *gin.Context) {
		fullPath := c.FullPath()
		c.HTML(http.StatusOK, "index.html", gin.H{
			"fullPath": fullPath,
			"title":    "gin教程",
		})
	})
	engine.Run() // listen and serve on 0.0.0.0:8080 (for windows "localhost:8080")
}

type Student struct {
	Id       int    `form:"id"`
	Username string `form:"username"`
}
type Register struct {
	Name     string `form:"name"`
	Phone    string `form:"phone"`
	Password string `form:"password"`
}
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二、模块化开发和中间件定义&使用

定义RouterGroup，定义中间件FullPathAndMethod()，打印请求路径和请求方法并返回响应状态码。

main.go

package main

import (
	"fmt"

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

func main() {
	// 模块化开发
	// 用户注册： /user/register
	// 用户登录： /user/login
	// 用户信息： /user/info
	// 用户删除： /user/id
	engine := gin.Default()

	rg := engine.Group("/user")
	rg.POST("/register", FullPathAndMethod(), registerHandler)
	rg.POST("/login", loginHandler)
	rg.DELETE("/:id", FullPathAndMethod(), deleteHandler)
	rg.GET("/info", FullPathAndMethod(), infoHandler)
	engine.Run()
}
func registerHandler(c *gin.Context) {
	fullPath := c.FullPath()
	if _, err := c.Writer.WriteString("FullPath: " + fullPath); err != nil {
		fmt.Printf("Write err: %v", err)
		return
	}
	fmt.Println("registerHandler handler")
}
func loginHandler(c *gin.Context) {
	fullPath := c.FullPath()
	if _, err := c.Writer.WriteString("FullPath: " + fullPath); err != nil {
		fmt.Printf("Write err: %v", err)
		return
	}
}
func deleteHandler(c *gin.Context) {
	fullPath := c.FullPath()
	id := c.Param("id")
	if _, err := c.Writer.WriteString("FullPath: " + fullPath + "\nDelete user id: " + id); err != nil {
		fmt.Printf("Write err: %v", err)
		return
	}
}
func infoHandler(c *gin.Context) {
	fullPath := c.FullPath()
	if _, err := c.Writer.WriteString("FullPath: " + fullPath); err != nil {
		fmt.Printf("Write err: %v", err)
		return
	}
}

// write an middleware to print request url fullpath and request method.
func FullPathAndMethod() gin.HandlerFunc {
	return func(c *gin.Context) {
		fullPath := c.FullPath()
		method := c.Request.Method
		fmt.Printf("fullPath: %v\n", fullPath)
		fmt.Printf("method: %v\n", method)
		c.Next()
		// 打印处理响应完成后的状态码
		httpCode := c.Writer.Status()
		fmt.Printf("响应状态码: %v\n", httpCode)
	}
}
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