Request body closed in copied context

[kenticny]

Description

I try to do some works with goroutine in handler as the demo, and when I read the request body from copied context in goroutine, the reader always closed. the error detail is http: invalid Read on closed Body

How to reproduce

package main

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

func main() {
	g := gin.Default()
	g.POST("/dosomething", func(c *gin.Context) {
		cCp := c.Copy()
                go func() {
                    var err error
		    var buf []byte
		    if buf, err = ioutil.ReadAll(cCp.Request.Body); err != nil {
                        log.Println(err)
			return
		    }
                    fmt.Println(string(buf))
                }()
	})
	g.Run(":9000")
}

Expectations

$ curl -XPOST -d '...some json data...' http://localhost:9000/dosomething

...json data...

Actual result

Show in stdout:

http: invalid Read on closed Body

Environment

• go version: go1.14.4 darwin/amd64
• gin version (or commit ref): v1.6.3
• operating system: MacOS 10.14.5

[yeqown]

your handler runs a new goroutine, so the handler finished then it called finishedRequest which would close the request body.

https://golang.org/src/net/http/server.go?s=89579:89620#L1930
https://golang.org/src/net/http/server.go?s=89579:89620#L1613