SSH tunnel to forward http port

http_ssh_tunnel.go

package main

// Forward from local port 8001 to remote port 9999, by ssh tunnel

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"

	"golang.org/x/crypto/ssh"
)

var (
	username         = "corvo"
	serverAddrString = "127.0.0.1:2222"
	remoteAddrString = "localhost:9999"
)

type indexHandler struct {
	content string
	config  *ssh.ClientConfig
}

func (ih *indexHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	sshClientConn, err := ssh.Dial("tcp", serverAddrString, ih.config)
	if err != nil {
		log.Fatalf("ssh.Dial failed: %s", err)
	}

	sshConn, err := sshClientConn.Dial("tcp", remoteAddrString)
	if err != nil {
		log.Fatalf("ssh.Dial failed: %s", err)
	}

	client, _, err := w.(http.Hijacker).Hijack()
	if err != nil {
		log.Fatalf("hjacker failed: %s", err)
	}

	// copy http header to the socket, bootstrap.
	data := req.Clone(req.Context())
	data.Write(sshConn)

	go func() {
		io.Copy(client, sshConn)
		client.Close()
		sshConn.Close()
	}()
	go func() {
		io.Copy(sshConn, client)
		client.Close()
		sshConn.Close()
	}()
}

func main() {
	// Setup SSH config (type *ssh.ClientConfig)
	config := &ssh.ClientConfig{
		User: username,
		HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error {
			return nil
		},
		// Auth: []ssh.AuthMethod{
		// 	ssh.Password(password),
		// },
	}
	http.Handle("/", &indexHandler{content: "hello world!", config: config})
	fmt.Println("Listen to http://127.0.0.1:8001")
	http.ListenAndServe("0.0.0.0:8001", nil)
}