add support for HTTPS proxy URL

README.md

@@ -1,11 +1,33 @@
 # go-ntlm-proxy-auth
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
-[![GoDoc](https://godoc.org/github.com/Codehardt/go-ntlm-proxy-auth?status.svg)](https://godoc.org/github.com/Codehardt/go-ntlm-proxy-auth)
+[![GoDoc](https://godoc.org/github.com/launchdarkly/go-ntlm-proxy-auth?status.svg)](https://godoc.org/github.com/launchdarkly/go-ntlm-proxy-auth)
 
 With this package, you can connect to http/https servers protected by an NTLM proxy in Golang.
 
-## Example
+This is a fork of https://github.com/Codehardt/go-ntlm-proxy-auth which adds support for HTTPS proxy URLs.
+
+## Example: NewNTLMProxyDialContext
+
+```golang
+// create a dialer
+dialer := &net.Dialer{
+    Timeout:   30 * time.Second,
+    KeepAlive: 30 * time.Second,
+}
+
+// wrap dial context with NTLM
+ntlmDialContext := newNTLMProxyDialContext(dialer, proxyURL, "user", "password", "domain", nil)
+
+// create a http(s) client
+client := &http.Client{
+    Transport: &http.Transport{
+        Proxy: nil, // !!! IMPORTANT, do not set proxy here !!!
+        DialContext: ntlmDialContext,
+    },
+}
+```
+## Example: WrapDialContext (deprecated - does not support HTTPS proxy URL)
 
 ```golang
 // create a dialer
@@ -21,9 +43,7 @@ ntlmDialContext := ntlm.WrapDialContext(dialer.DialContext, "proxyAddr", "user",
 client := &http.Client{
     Transport: &http.Transport{
         Proxy: nil, // !!! IMPORTANT, do not set proxy here !!!
-        Dial: dialer.Dial,
         DialContext: ntlmDialContext,
-        // TLSClientConfig: ...
     },
 }
 ```

ntlm.go

@@ -3,6 +3,7 @@ package ntlm
 import (
 	"bufio"
 	"context"
+	"crypto/tls"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -23,10 +24,36 @@ import (
 // dialContext := (&net.Dialer{KeepAlive: 30*time.Second, Timeout: 30*time.Second}).DialContext
 type DialContext func(ctx context.Context, network, addr string) (net.Conn, error)
 
-// WrapDialContext wraps a DialContext with an NTLM Authentication to a proxy.
+// NewNTLMProxyDialContext provides a DialContext function that includes transparent NTLM proxy authentication.
+// Unlike WrapDialContext, it describes the proxy location with a full URL, whose scheme can be HTTP or HTTPS.
+func NewNTLMProxyDialContext(dialer *net.Dialer, proxyURL url.URL, proxyUsername, proxyPassword, proxyDomain string, tlsConfig *tls.Config) DialContext {
+	if dialer == nil {
+		dialer = &net.Dialer{}
+	}
+	return func(ctx context.Context, network, addr string) (net.Conn, error) {
+		dialProxy := func() (net.Conn, error) {
+			debugf("ntlm> Will connect to proxy at " + proxyURL.Host)
+			if proxyURL.Scheme == "https" {
+				return tls.DialWithDialer(dialer, "tcp", proxyURL.Host, tlsConfig)
+			}
+			return dialer.DialContext(ctx, network, proxyURL.Host)
+		}
+		return dialAndNegotiate(addr, proxyUsername, proxyPassword, proxyDomain, dialProxy)
+	}
+}
+
+// WrapDialContext wraps a DialContext with an NTLM Authentication to a proxy. Note that this does not support
+// using HTTPS to connect to the proxy; use NewNTLMProxyDialContext if that is required.
 func WrapDialContext(dialContext DialContext, proxyAddress, proxyUsername, proxyPassword, proxyDomain string) DialContext {
 	return func(ctx context.Context, network, addr string) (net.Conn, error) {
-		conn, err := dialContext(ctx, network, proxyAddress)
+		return dialAndNegotiate(addr, proxyUsername, proxyPassword, proxyDomain, func() (net.Conn, error) {
+			return dialContext(ctx, network, proxyAddress)
+		})
+	}
+}
+
+func dialAndNegotiate(addr, proxyUsername, proxyPassword, proxyDomain string, baseDial func() (net.Conn, error)) (net.Conn, error) {
+	conn, err := baseDial()
 	if err != nil {
 		debugf("ntlm> Could not call dial context with proxy: %s", err)
 		return conn, err
@@ -112,4 +139,3 @@ func WrapDialContext(dialContext DialContext, proxyAddress, proxyUsername, proxy
 	debugf("ntlm> Successfully injected NTLM to connection")
 	return conn, nil
 }
-}