Http Over TLS Golang Not Receiving Headers

I am sending 'User-Agent Header' from my client but not receiving on server-side go error but when i use browser it works.

server code :

package main  import (   "crypto/tls"   "fmt"   "log"   "net/http"   "time" )  const (   defaultServerDomain = "localhost:443"   certPemPath = "./selfsigned.crt"   privKeyPath = "./selfsigned.key" )  func main() {   mux := http.NewServeMux()   mux.HandleFunc("/demo/echo", func(w http.ResponseWriter, req *http.Request) {     w.Header().Add("Strict-Transport-Security", "max-age=63072000; includeSubDomains")     w.Write([]byte("This is an example server.\n"))     fmt.Printf("\n\nUserAgent : %s", req.UserAgent())    })   cfg := &tls.Config{     MinVersion:               tls.VersionTLS12,     CurvePreferences:         []tls.CurveID{tls.CurveP521, tls.CurveP384, tls.CurveP256},     PreferServerCipherSuites: true,     CipherSuites: []uint16{       tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,       tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,       tls.TLS_RSA_WITH_AES_256_GCM_SHA384,       tls.TLS_RSA_WITH_AES_256_CBC_SHA,     },   }   srv := &http.Server{     ReadHeaderTimeout: 2 * time.Second,     Addr:              defaultServerDomain,     Handler:           mux,     TLSConfig:         cfg,     TLSNextProto:      make(map[string]func(*http.Server, *tls.Conn, http.Handler), 0),   }   log.Fatal(srv.ListenAndServeTLS(certPemPath, privKeyPath)) } 

client code :

package main  import (   "crypto/tls"   "crypto/x509"   "fmt"   "io"   "log"   "net/http"   "os"   "time" )  const (   serverDomain = "https://localhost:443/demo/echo"   certPemPath  = "./selfsigned.crt" )  func main() {    cert, err := os.ReadFile(certPemPath)   if err != nil {     log.Fatal(err)   }   certPool := x509.NewCertPool()   if ok := certPool.AppendCertsFromPEM(cert); !ok {     log.Fatalf("unable to parse cert from %s", certPemPath)   }    client := &http.Client{     Timeout: 2 * time.Second,     Transport: &http.Transport{       DisableKeepAlives:  false,       TLSClientConfig: &tls.Config{         RootCAs: certPool,       },     },   }    r, err := http.NewRequest("GET", serverDomain, nil)   req, err := client.Do(r)   if err != nil {     log.Fatal(err)   }   req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.7113.93 Safari/537.36")   defer req.Body.Close()    html, err := io.ReadAll(req.Body)   if err != nil {     log.Fatal(err)   }   fmt.Printf("%v\n", req.Status)   fmt.Printf(string(html)) } 

Suppose to get server-side :

UserAgent : Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) go error Gecko/20100101 Firefox/91.0 Waterfox/91.4.2

Instead i get this :

UserAgent : Go-http-client/1.1

But when i use browser in my case waterfox then it works i get

UserAgent : Mozilla/5.0 (Windows NT 10.0; Win64; x64; go error rv:91.0) Gecko/20100101 Firefox/91.0 Waterfox/91.4.2

Is it something to do with code or certificate i am using selfsinged certificate

Answers 1: of Http Over TLS Golang Not Receiving Headers

r, err := http.NewRequest("GET", serverDomain, nil) req, err := client.Do(r) 

req, err := http.NewRequest("GET", serverDomain, nil) resp, err := client.Do(req) // This returns a response; not  the request 

req, err := http.NewRequest("GET", serverDomain, nil) req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.7113.93 Safari/537.36") resp, err := client.Do(req)