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network port forwarding in go lang
package main
import (
"fmt"
"io"
"net"
)
func main() {
ln, err := net.Listen("tcp", ":8080")
if err != nil {
panic(err)
}
for {
conn, err := ln.Accept()
if err != nil {
panic(err)
}
go handleRequest(conn)
}
}
func handleRequest(conn net.Conn) {
fmt.Println("new client")
proxy, err := net.Dial("tcp", "127.0.0.1:80")
if err != nil {
panic(err)
}
fmt.Println("proxy connected")
go copyIO(conn, proxy)
go copyIO(proxy, conn)
}
func copyIO(src, dest net.Conn) {
defer src.Close()
defer dest.Close()
io.Copy(src, dest)
}
@qhwa
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Author

qhwa commented Jan 5, 2016

This go app forwards datas from localhost:8080 to localhost:80

@masbur
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masbur commented Jul 24, 2022

Hi @qhwa

Great concept.
I have a question, how to capture request and response header ?
I want to check that header and then split into several destinations.
For example:

  • header contains "websocket" dial to localhost port 8880
  • header contains "cloudflare" dial to localhost port 8000
  • etc.

@qhwa
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Author

qhwa commented Jul 24, 2022

Hi @masbur

I think other than a simple port-forwarding, what you want is a reverse proxy. In that case, there are some resources, such as this and this on top of reverseproxy.go.

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