一、概述
在 Gin 框架中，中间件（Middleware）是一种在处理 HTTP 请求之前或之后执行的函数。使用中间件可以方便地实现诸如身份验证（Auth）、日志记录、请求限流等功能。
二、编写中间件
// 中间件
func StartCost1(c *gin.Context) {
log.Info("......start1......")
start := time.Now()
c.Next() //调用后续的处理函数
// c.Abort() //阻止调用后续的处理函数
cost := time.Since(start)
log.Info("cost1:", cost)
log.Info("......end1......")
}
func StartCost2(c *gin.Context) {
log.Info("......start2......")
log.Info("......end2......")
}
func authMiddleware(doCheck bool) gin.HandlerFunc {
return func(ctx *gin.Context) {
if doCheck {
//检查用户信息
ctx.Set("token", "20240814")
// TODO
log.Info("检查用户登录信息")
ctx.Next()
} else {
//不检查用户信息
log.Error("不检查用户信息即可处理")
ctx.Next()
}
}
}三、使用中间件
func main() {
r := gin.Default()
r.Use(StartCost1, StartCost2, authMiddleware(true))
r.LoadHTMLFiles("./index.html", "./home.html")
r.GET("/web", func(c *gin.Context) {
name := c.Query("query")
c.JSON(http.StatusOK, gin.H{
"name": name,
})
})
r.GET("/login", func(ctx *gin.Context) {
ctx.HTML(http.StatusOK, "index.html", nil)
})
r.GET("/home", func(ctx *gin.Context) {
ctx.Request.URL.Path = "/b"
r.HandleContext(ctx)
})
r.GET("/b", func(ctx *gin.Context) {
log.Info("request /b GetLocalIP: " + GetLocalIP())
ctx.Redirect(http.StatusMovedPermanently, GetLocalIP()+":9090/login")
})
r.POST("/login", func(ctx *gin.Context) {
log.Info("request /login GetLocalIP: " + GetLocalIP())
username := ctx.PostForm("username")
password := ctx.PostForm("password")
//从请求中获取携带的参数
f, err := ctx.FormFile("file")
if err != nil {
ctx.JSON(http.StatusBadRequest, gin.H{
"error": err,
})
} else {
filePath := path.Join("./", f.Filename)
ctx.SaveUploadedFile(f, filePath)
ctx.HTML(http.StatusOK, "home.html", gin.H{
"Name": username,
"Password": password,
"Token": ctx.GetString("token"),
})
}
})
r.Run(":9090")
}四、后端完整代码
package main
import (
"net"
"net/http"
"path"
"time"
"github.com/gin-gonic/gin"
log "github.com/sirupsen/logrus"
)
func GetLocalIP() string {
ip := "127.0.0.1"
addrs, err := net.InterfaceAddrs()
if err != nil {
return ip
}
for _, a := range addrs {
if ipnet, ok := a.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
if ipnet.IP.To4() != nil {
ip = ipnet.IP.String()
break
}
}
}
return ip
}
// 中间件
func StartCost1(c *gin.Context) {
log.Info("......start1......")
start := time.Now()
c.Next() //调用后续的处理函数
// c.Abort() //阻止调用后续的处理函数
cost := time.Since(start)
log.Info("cost1:", cost)
log.Info("......end1......")
}
func StartCost2(c *gin.Context) {
log.Info("......start2......")
log.Info("......end2......")
}
func authMiddleware(doCheck bool) gin.HandlerFunc {
return func(ctx *gin.Context) {
if doCheck {
//检查用户信息
ctx.Set("token", "20240814")
// TODO
log.Info("检查用户登录信息")
ctx.Next()
} else {
//不检查用户信息
log.Error("不检查用户信息即可处理")
ctx.Next()
}
}
}
func main() {
r := gin.Default()
r.Use(StartCost1, StartCost2, authMiddleware(true))
r.LoadHTMLFiles("./index.html", "./home.html")
r.GET("/web", func(c *gin.Context) {
name := c.Query("query")
c.JSON(http.StatusOK, gin.H{
"name": name,
})
})
r.GET("/login", func(ctx *gin.Context) {
ctx.HTML(http.StatusOK, "index.html", nil)
})
r.GET("/home", func(ctx *gin.Context) {
ctx.Request.URL.Path = "/b"
r.HandleContext(ctx)
})
r.GET("/b", func(ctx *gin.Context) {
log.Info("request /b GetLocalIP: " + GetLocalIP())
ctx.Redirect(http.StatusMovedPermanently, GetLocalIP()+":9090/login")
})
r.POST("/login", func(ctx *gin.Context) {
log.Info("request /login GetLocalIP: " + GetLocalIP())
username := ctx.PostForm("username")
password := ctx.PostForm("password")
//从请求中获取携带的参数
f, err := ctx.FormFile("file")
if err != nil {
ctx.JSON(http.StatusBadRequest, gin.H{
"error": err,
})
} else {
filePath := path.Join("./", f.Filename)
ctx.SaveUploadedFile(f, filePath)
ctx.HTML(http.StatusOK, "home.html", gin.H{
"Name": username,
"Password": password,
"Token": ctx.GetString("token"),
})
}
})
r.Run(":9090")
}
五、前端页面
1、index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Form</title>
</head>
<body>
<form action="/login" method="post" enctype="multipart/form-data">
<div>
<label for="username">用户名：</label>
<input type="text" name="username" id="username" />
</div>
<div>
<label for="password">密 码：</label>
<input type="text" name="password" id="password" />
</div>
<div>
<label for="file">上传文件：</label>
<input type="file" name="file" id="file" />
</div>
<div>
<input type="submit" value="提交">
</div>
</form>
</body>
</html>2、home.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>用户信息</title>
</head>
<body>
<h1> 您好，{{.Name}}</h1>
<span>密码：{{.Password}}</span>
<span>Token：{{.Token}}</span>
</body>
</html>六、运行代码
go run main.go
七、展示
