HTTPS Listener For HTTP Redirect

If client sent an HTTP request to an HTTPS server port, returns 302 redirection, like nginx's "error_page 497".

Related issue: golang/go#49310

Simple version: simplehlfhr

---

Get

go get github.com/bddjr/hlfhr

---

Example

// Use hlfhr.New
srv := hlfhr.New(&http.Server{
	// Write something...
})
// Then just use it like [http.Server]
err := srv.ListenAndServeTLS("localhost.crt", "localhost.key")

---

Logic

flowchart TD
	Read("Hijacking net.Conn.Read")

	IsLooksLikeHTTP("First byte looks like HTTP?")

	Continue(["✅ Continue..."])

	ReadRequest("🔍 Read request")

	IsFindHostHeader("Find Host header?")

	IsHandlerExist("`
	HttpOnHttpsPort
	ErrorHandler
	exist?`")

	302Redirect{{"🟡 302 Redirect"}}

	Handler{{"💡 Handler"}}

	Close(["❌ Close."])

    Read --> IsLooksLikeHTTP
    IsLooksLikeHTTP -- "🔐false" --> Continue
    IsLooksLikeHTTP -- "📄true" --> ReadRequest --> IsFindHostHeader
    IsFindHostHeader -- "⛔false" --> Close
    IsFindHostHeader -- "✅true" --> IsHandlerExist
	IsHandlerExist -- "✖false" --> 302Redirect --> Close
	IsHandlerExist -- "✅true" --> Handler --> Close

Loading

See

• curl
• src_server.go
• src_listener.go
• src_conn.go
• src_conn-looks-like-http.go

---

Option Example

HttpOnHttpsPortErrorHandler

// 307 Temporary Redirect
srv.HttpOnHttpsPortErrorHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	hlfhr.RedirectToHttps(w, r, 307)
})

// Check Host Header
srv.HttpOnHttpsPortErrorHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	hostname, port := hlfhr.SplitHostnamePort(r.Host)
	switch hostname {
	case "localhost":
		//
	case "www.localhost", "127.0.0.1":
		r.Host = hlfhr.HostnameAppendPort("localhost", port)
	default:
		w.WriteHeader(421)
		return
	}
	hlfhr.RedirectToHttps(w, r, 302)
})

// Script Redirect
srv.HttpOnHttpsPortErrorHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/html")
	w.WriteHeader(300)
	io.WriteString(w, "<script>location.protocol='https:'</script>")
})

---

Method Example

New

srv := hlfhr.New(&http.Server{
	// Write something...
})

NewServer

srv := hlfhr.NewServer(&http.Server{
	// Write something...
})

ListenAndServeTLS

// Just use it like [http.ListenAndServeTLS]
var h http.Handler
err := hlfhr.ListenAndServeTLS(":443", "localhost.crt", "localhost.key", h)

ServeTLS

// Just use it like [http.ServeTLS]
var l net.Listener
var h http.Handler
err := hlfhr.ServeTLS(l, h, "localhost.crt", "localhost.key")

NewListener

var l net.Listener
var srv *http.Server
var HttpOnHttpsPortErrorHandler http.Handler
l = hlfhr.NewListener(l, srv, HttpOnHttpsPortErrorHandler)

Redirect

var w http.ResponseWriter
hlfhr.Redirect(w, 302, "https://example.com/")

RedirectToHttps

var w http.ResponseWriter
var r *http.Request
hlfhr.RedirectToHttps(w, r, 302)

SplitHostnamePort

hostname, port := hlfhr.SplitHostnamePort("[::1]:5678")
// hostname: [::1]
// port: 5678

Hostname

hostname := hlfhr.Hostname("[::1]:5678")
// hostname: [::1]

Port

port := hlfhr.Port("[::1]:5678")
// port: 5678

HostnameAppendPort

Host := hlfhr.HostnameAppendPort("[::1]", "5678")
// Host: [::1]:5678

ReplaceHostname

Host := hlfhr.ReplaceHostname("[::1]:5678", "localhost")
// Host: localhost:5678

ReplacePort

Host := hlfhr.ReplacePort("[::1]:5678", "7890")
// Host: [::1]:7890

Ipv6CutPrefixSuffix

v6 := hlfhr.Ipv6CutPrefixSuffix("[::1]")
// v6: ::1

IsHttpServerShuttingDown

var srv *http.Server
isShuttingDown := hlfhr.IsHttpServerShuttingDown(srv)

Server.IsShuttingDown

var srv *hlfhr.Server
isShuttingDown := srv.IsShuttingDown()

NewResponse

var c net.Conn
var h http.Handler
var r *http.Request

w := NewResponse()

h.ServeHTTP(w, r)
err := w.Flush(c)

ConnFirstByteLooksLikeHttp

b := []byte("GET / HTTP/1.1\r\nHost: localhost\r\n\r\n")
looksLikeHttp := hlfhr.ConnFirstByteLooksLikeHttp(b[0])

NewBufioReaderWithBytes

var c net.Conn
var b []byte
n, err := c.Read(b)
br := hlfhr.NewBufioReaderWithBytes(b, n, c)

---

Test

git clone https://github.com/bddjr/hlfhr
cd hlfhr
./run.sh

---

Reference

https://developer.mozilla.org/docs/Web/HTTP/Session
https://developer.mozilla.org/docs/Web/HTTP/Methods
https://developer.mozilla.org/docs/Web/HTTP/Redirections
https://developer.mozilla.org/docs/Web/HTTP/Status/302
https://developer.mozilla.org/docs/Web/HTTP/Status/307
https://developer.mozilla.org/docs/Web/HTTP/Headers/Connection

https://tls12.xargs.org/#client-hello
https://tls13.xargs.org/#client-hello

https://nginx.org/en/docs/http/ngx_http_ssl_module.html#errors

golang/go#49310
golang/go#66501

"net/http"
"net"
"crypto/tls"
"reflect"
"bufio"
"bytes"

---

License

BSD-3-clause license