Lesson 2.5: 中间件开发
学习目标
- 掌握常见中间件的实现模式
- 理解中间件链的执行流程
1. 日志中间件
go
func Logger() gin.HandlerFunc {
return func(c *gin.Context) {
start := time.Now()
path := c.Request.URL.Path
// 处理请求
c.Next()
// 请求结束后记录
latency := time.Since(start)
status := c.Writer.Status()
log.Printf("[%d] %s %s %v",
status,
c.Request.Method,
path,
latency,
)
}
}2. CORS 中间件
go
func CORS(allowedOrigins []string) gin.HandlerFunc {
return func(c *gin.Context) {
origin := c.Request.Header.Get("Origin")
for _, allowed := range allowedOrigins {
if origin == allowed || allowed == "*" {
c.Header("Access-Control-Allow-Origin", origin)
break
}
}
c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
c.Header("Access-Control-Allow-Headers", "Content-Type, Authorization")
c.Header("Access-Control-Max-Age", "86400")
if c.Request.Method == "OPTIONS" {
c.AbortWithStatus(204)
return
}
c.Next()
}
}3. 限流中间件
go
func RateLimit(rate int, burst int) gin.HandlerFunc {
limiter := rate.NewLimiter(rate.Limit(rate), burst)
return func(c *gin.Context) {
if !limiter.Allow() {
c.AbortWithStatusJSON(429, gin.H{
"error": "too many requests",
})
return
}
c.Next()
}
}