Go中Gin中间件的实现

func LoggerHandler() gin.HandlerFunc  {
	
	return func(c *gin.Context) {
		log.Printf("%s %s %s", c.Request.Method, c.Request.RequestURI, c.ClientIP())
		c.Next()
	}
}

package main

import (
	"github.com/gin-gonic/gin"
	"log"
)

func main() {
	request := gin.Default()
	//使用中间件
	request.Use(LoggerHandler())
	
	//定义一个路由处理器.
	request.GET("/test", func(c *gin.Context) {
		c.JSON(200, gin.H{
			"message": "hello world",
		})
	})
	request.Run()
}

package main

import (
	"github.com/gin-gonic/gin"
	"log"
)

func main() {
	request := gin.Default()
	//定义中间件
	request.Use(func(c *gin.Context) {
		c.Set("name", "itBo")
		c.Next()
	})

	//定义一个路由处理器.
	request.GET("/", func(c *gin.Context) {
		name, exists := c.Get("name")

		if !exists {
			c.String(200, "用户名不存在")
			return
		}

		c.String(200, "你好,%s", name)
	})
	request.Run()
}

package main

import (
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
	"time"
)

func main() {
	request := gin.Default()
	//定义中间件
	request.Use(myMiddlewareHandler())

	//定义一个路由处理器.
	request.GET("/", func(c *gin.Context) {
		c.String(http.StatusOK, "Hello World")
	})
	request.Run()
}

func myMiddlewareHandler() gin.HandlerFunc {
	return func(c *gin.Context) {
		//请求前操作.
		startTime := time.Now()
		c.Set("startTime", startTime)
		//处理请求.
		c.Next()
		//请求后的操作,计算处理时间并记录日志.
		endTime := time.Since(startTime)
		log.Printf("请求处理时间: %s", endTime)
	}
}

package main

import (
	"github.com/gin-gonic/gin"
	"log"
	"net/http"
	"sync"
	"time"
)

type RateLimiter struct {
	sync.Mutex
	Requests map[string]int
}

func RateLimiterHandler(rateLimiter *RateLimiter, limit int, interval time.Duration) gin.HandlerFunc {
	return func(c *gin.Context) {
		ip := c.ClientIP()

		rateLimiter.Lock()
		requests := rateLimiter.Requests[ip]
		if requests >= limit {
			rateLimiter.Unlock()
			c.AbortWithStatusJSON(http.StatusTooManyRequests, gin.H{"error": "request too many"})
			return
		}
		rateLimiter.Requests[ip] = requests + 1
		rateLimiter.Unlock()

		//在指定时间后,减少请求次数.
		go func() {
			time.Sleep(interval)
			rateLimiter.Lock()
			rateLimiter.Requests[ip]--
			if rateLimiter.Requests[ip] <= 0 {
				delete(rateLimiter.Requests, ip)
			}
			rateLimiter.Unlock()
		}()
		c.Next()
	}
}

func main() {
	request := gin.Default()
	//设置速率限制中间件
	rateLimit := &RateLimiter{Requests: make(map[string]int)}
	request.Use(RateLimiterHandler(rateLimit, 2, 5*time.Minute))

	//定义一个路由处理器.
	request.GET("/", func(c *gin.Context) {
		c.String(http.StatusOK, "Hello World")
	})
	request.Run()
}