Go language web development series 26: Gin framework: demonstrates the execution sequence of code when there are multiple middleware

One , Libraries required for installation

1,gin In the framework of github The address of :

https://github.com/gin-gonic/gin

2, Install... From the command line :

[email protected]:/data/go/ginhello# go get -u github.com/gin-gonic/[email protected]

explain ： Liu Hongdi's go The forest is a focus golang The blog of ,
           Address ：https://blog.csdn.net/weixin_43881017

explain ： author : Liu Hongdi mailbox : [email protected]

Two , Information about the demonstration project

1, Project address :

https://github.com/liuhongdi/digv26

2, Functional specifications ： Demonstrate using multiple middleware（ middleware ） when ,middleware The execution order of the code in

3, Project structure ： Pictured :

3、 ... and ,go Code instructions

1,middleware/middle.go

package middleware

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"time"
)
// first middleware
func MiddlewareOne() gin.HandlerFunc {
	return func(c *gin.Context) {
		fmt.Println("before middlewareOne: "+time.Now().String())
		c.Next()
		fmt.Println("after middlewareOne: "+time.Now().String())
		return
	}
}
// the second middleware
func MiddlewareTwo() gin.HandlerFunc {
	return func(c *gin.Context) {
		fmt.Println("before middlewareTwo: "+time.Now().String())
		c.Next()
		fmt.Println("after middlewareTwo: "+time.Now().String())
		return
	}
}
// Third middleware
func MiddlewareThree() gin.HandlerFunc {
	return func(c *gin.Context) {
		fmt.Println("before MiddlewareThree: "+time.Now().String())
		c.Next()
		fmt.Println("after MiddlewareThree: "+time.Now().String())
		return
	}
}

2,router/router.go

package router

import (
	"github.com/gin-gonic/gin"
	"github.com/liuhongdi/digv26/controller"
	"github.com/liuhongdi/digv26/global"
	"github.com/liuhongdi/digv26/middleware"
	"log"
	"runtime/debug"
)

func Router() *gin.Engine {
	router := gin.Default()
	// Handling exceptions 
	router.NoRoute(HandleNotFound)
	router.NoMethod(HandleNotFound)
	//use middleware
	router.Use(middleware.MiddlewareTwo())
	router.Use(middleware.MiddlewareOne())
	router.Use(middleware.MiddlewareThree())
	router.Use(Recover)
	//  Path mapping :index
	indexc:=controller.NewIndexController()
	router.GET("/index/index", indexc.Index);

	return router
}

func HandleNotFound(c *gin.Context) {
	global.NewResult(c).Error(404," Resource not found ")
	return
}

func Recover(c *gin.Context) {
	defer func() {
		if r := recover(); r != nil {
			// Print error stack information 
			log.Printf("panic: %v\n", r)
			debug.PrintStack()
			global.NewResult(c).Error(500," Server internal error ")
		}
	}()
	// Finished loading  defer recover, Continue with subsequent interface calls 
	c.Next()
}

3,controller/indexController.go

package controller

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/liuhongdi/digv26/global"
	"time"
)

type IndexController struct{}
func NewIndexController() IndexController {
	return IndexController{}
}
// Return a successful prompt 
func (g *IndexController) Index(c *gin.Context) {
	fmt.Println("controller:index: "+time.Now().String())
	result := global.NewResult(c)
	result.Success("success");
	return
}

 

Four , The test results

visit :

http://127.0.0.1:8080/index/index

return :

Look at the output of the console :

before middlewareTwo: 2021-02-03 11:52:29.84260954 +0800 CST m=+3.560203369
before middlewareOne: 2021-02-03 11:52:29.842749172 +0800 CST m=+3.560342999
before MiddlewareThree: 2021-02-03 11:52:29.842758214 +0800 CST m=+3.560352049
controller:index: 2021-02-03 11:52:29.842761431 +0800 CST m=+3.560355255
after MiddlewareThree: 2021-02-03 11:52:29.842819585 +0800 CST m=+3.560413419
after middlewareOne: 2021-02-03 11:52:29.842825746 +0800 CST m=+3.560419571
after middlewareTwo: 2021-02-03 11:52:29.842828523 +0800 CST m=+3.560422350

You can see ：

There are many. middleware when

about next Previous code , Is in accordance with the use The order of takes effect ,

and next Later code , It takes effect in the reverse order

5、 ... and , View the version of the library :

module github.com/liuhongdi/digv26

go 1.15

require (
	github.com/gin-gonic/gin v1.6.3
)