Matt:
Thank you so much for pointing this point. You are totally correct. As a
newly minted Go programmer I failed to see that. I have the code working now…
Your help is very much appreciated.
HFC
From: Matt Harden
Date: Saturday, February 25, 2017 at 12:01 PM
To: Henry Camacho, golang-nuts
Subject: Re: [go-nuts] Passing Already Accepted Connection to http.Serve()
You're not waiting for the server to finish handling the connection before
returning from main, which abruptly ends your program. Try importing context
and using this at the end of main() (note that Shutdown was recently added):
ctx := context.TODO()
server := http.Server{}
if err := server.Serve(wedgeListener); err != nil {
loginfo.Println("Serve: ", err)
}
if err := server.Shutdown(ctx); err != nil {
loginfo.Println("Shutdown: ", err)
}
On Thu, Feb 23, 2017 at 8:41 PM <[email protected]> wrote:
I am attempting to pass an already accepted connection to http.Serve(). I need
to preview the connection allowing inspection of type of traffic appearing on a
single port.
The desire is to handle a number of types of connections to a single port.
I'll preview the traffic, determine what type it is, and then pass it off to
the appropriate handler.
I understand that I need a net.Listener interface.
Testing code:
package main
import (
"fmt"
"net"
"net/http"
)
func main() {
loginfo.Println("startup")
listener, err := net.Listen("tcp", ":8080")
if err != nil {
loginfo.Println("unable to bind ")
return
}
conn, err := listener.Accept()
if err != nil {
loginfo.Println("unable to bind", err)
return
}
wedgeListener := &WedgeListener{conn: conn}
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
loginfo.Println("/")
})
err = http.Serve(wedgeListener, nil)
if err != nil {
loginfo.Println("Serve: ", err)
}
}
func connState(conn net.Conn, state http.ConnState) {
loginfo.Println("connState")
fmt.Println(conn, conn.LocalAddr(), conn.RemoteAddr())
fmt.Println(state)
}
//WedgeListener -- used to hand off connections to other protocols via Listen
type WedgeListener struct {
conn net.Conn
once sync.Once
}
//Accept --
func (s *WedgeListener) Accept() (net.Conn, error) {
var c net.Conn
loginfo.Println("Accept")
s.once.Do(func() {
loginfo.Println("Do Once")
c = s.conn
})
if c != nil {
loginfo.Println("accepted")
return c, nil
}
return nil, io.EOF
}
//Close --
func (s *WedgeListener) Close() error {
s.once.Do(func() {
loginfo.Println("close called")
s.conn.Close()
})
return nil
}
//Addr --
func (s *WedgeListener) Addr() net.Addr {
loginfo.Println("Add Called", s.conn.LocalAddr())
return s.conn.LocalAddr()
}
When I hit the listener I see the following:
INFO: main: 2017/02/23 19:44:46.339133 main.go:10: startup
INFO: main: 2017/02/23 19:45:06.887653 wedge_listener.go:56: Add Called
192.168.1.158:8080
INFO: main: 2017/02/23 19:45:06.887668 wedge_listener.go:20: Accept
INFO: main: 2017/02/23 19:45:06.887671 wedge_listener.go:34: Do Once
INFO: main: 2017/02/23 19:45:06.887673 wedge_listener.go:39: accepted
INFO: main: 2017/02/23 19:45:06.887685 wedge_listener.go:20: Accept
INFO: main: 2017/02/23 19:45:06.887692 main.go:32: Serve: EOF
It appears to me that http.Serve() does not like the connection I've provided
via WedgeListener. It dumps the 1st connection and tries to get another.
The WedgeListener works just fine Accepted:
wConn, err := wedgeListener.Accept()
if err != nil {
loginfo.Println("Bad accept ", err)
return
}
cnt, err := wConn.Read(buffer[0:])
if err != nil {
loginfo.Println(err)
return
}
loginfo.Println("byte read", cnt)
loginfo.Println(hex.Dump(buffer[0:cnt]))
I get data back, works great.
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