tls_handshake.go

package main

import (
	"context"
	"crypto/tls"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"net/http/httptest"
	"net/url"
	"time"
)

func main() {
	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello, %s", r.Proto)
	}))
	ts.EnableHTTP2 = true
	ts.StartTLS()

	u, err := url.Parse(ts.URL)
	if err != nil {
		panic(err)
	}

	tlsConfig := &tls.Config{
		ServerName:         "fake",
		InsecureSkipVerify: false,
	}

	dialer := &net.Dialer{
		Timeout: 30 * time.Second,
	}

	c, err := dialer.DialContext(context.TODO(), "tcp", u.Host)
	if err != nil {
		log.Println(err)
		return
	}

	tlsConn := tls.Client(c, tlsConfig)
	if err := tlsConn.HandshakeContext(context.TODO()); err != nil {
		log.Println("HANDSHAKE error", err)
	}

	tlsDialer := tls.Dialer{
		NetDialer: dialer,
		Config:    tlsConfig,
	}

	conn, err := tlsDialer.DialContext(context.TODO(), "tcp", u.Host)
	if err != nil {
		log.Println("TLS DIALER ERROR", err)
	}
	defer conn.Close()

	n, err := conn.Write([]byte("hello\n"))
	if err != nil {
		log.Println(n, err)
		return
	}

	buf := make([]byte, 100)
	n, err = conn.Read(buf)
	if err != nil {
		log.Println(n, err)
		return
	}

	fmt.Println(string(buf[:n]))

	client := ts.Client()
	resp, err := client.Get(ts.URL)
	if err != nil {
		// handle error
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)

	if string(data) != "Hello, HTTP/2.0" {
		panic("unexpected response")
	}

}