How can I use a uTLS connection when sending a request? - http

Question

I'm trying to send a request using a Hello Chrome fingerprint by using the uTLS library, but after looking through the docs I'm struggling to figure out how to utilise the uTLS connection when sending a request.
I've got both parts of the code below, but not sure how to put them together, or if I'm even doing it the correct way.
package main
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/cookiejar"
tls "github.com/refraction-networking/utls"
)
func main() {
tcpConn, err := net.Dial("tcp", "151.101.65.69:443")
if err != nil {
fmt.Printf("net.Dial() failed: %+v\n", err)
return
}
config := tls.Config{ServerName: "www.stackoverflow.com"}
tlsConn := tls.UClient(tcpConn, &config, tls.HelloChrome_Auto)
defer tlsConn.Close()
err = tlsConn.Handshake()
if err != nil {
fmt.Printf("uTlsConn.Handshake() error: %+v", err)
} else {
fmt.Println("Handshake met")
}
cookieJar, _ := cookiejar.New(nil)
client := &http.Client{
Jar: cookieJar,
Transport: &http.Transport{},
}
req, err := http.NewRequest("GET", "https://ja3er.com/json", nil)
req.Header.Add("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36")
resp, err := client.Do(req)
if err != nil {
fmt.Println(err)
} else {
fmt.Println(resp.StatusCode)
body, _ := ioutil.ReadAll(resp.Body)
fmt.Println(string(body))
}
}

Answer 1

Simply move your code into Transport.DialTLSContext:
DialTLSContext specifies an optional dial function for creating
TLS connections for non-proxied HTTPS requests.
[...]
The returned net.Conn is assumed to already be
past the TLS handshake.
client := &http.Client{
Jar: cookieJar,
Transport: &http.Transport{
DialTLSContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
// Note that hardcoding the address is not necessary here. Only
// do that if you want to ignore the DNS lookup that already
// happened behind the scenes.
tcpConn, err := (&net.Dialer{}).DialContext(ctx, network, addr)
if err != nil {
return nil, err
}
config := tls.Config{ServerName: "www.stackoverflow.com"}
tlsConn := tls.UClient(tcpConn, &config, tls.HelloChrome_Auto)
err = tlsConn.Handshake()
if err != nil {
return nil, fmt.Errorf("uTlsConn.Handshake() error: %w", err)
}
return tlsConn, nil
},
},
}