Gin 框架中的 c.Next() 的作用

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package main  
  
import (  
   "fmt"  
   "net/http"
   
   "github.com/gin-gonic/gin"
)  
  
func main() {  
   r := gin.New()  
  
   r.Use(func(c *gin.Context) {  
      fmt.Println("in mid1")  
      
      // 执行下一个中间件，并返回到当前函数
      c.Next() 
      
      // 该行代码会在 next 之后继续执行
      fmt.Println("haha") 
   })  
  
   r.Use(func(c *gin.Context) {  
      fmt.Println("in mid2")  
   })  
  
   r.GET("/hello", func(c *gin.Context) {  
      c.JSON(http.StatusOK, gin.H{  
         "message": "ok",  
      })  
   })  
  
   r.Run(":8080")  
}

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in mid1
in mid2
haha

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// Next should be used only inside middleware.// It executes the pending handlers in the chain inside the calling handler.  
// See example in GitHub.  
func (c *Context) Next() {  
   c.index++  
   for c.index < int8(len(c.handlers)) {  
      c.handlers[c.index](c)  
      c.index++  
   }  
}