Merge pull request #363 from micro/proxy

Add support for http proxy

transport/http_proxy.go

@@ -0,0 +1,109 @@
+package transport
+
+import (
+	"bufio"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+)
+
+const (
+	proxyAuthHeader = "Proxy-Authorization"
+)
+
+func getURL(addr string) (*url.URL, error) {
+	r := &http.Request{
+		URL: &url.URL{
+			Scheme: "https",
+			Host:   addr,
+		},
+	}
+	return http.ProxyFromEnvironment(r)
+}
+
+type pbuffer struct {
+	net.Conn
+	r io.Reader
+}
+
+func (p *pbuffer) Read(b []byte) (int, error) {
+	return p.r.Read(b)
+}
+
+func proxyDial(conn net.Conn, addr string, proxyURL *url.URL) (_ net.Conn, err error) {
+	defer func() {
+		if err != nil {
+			conn.Close()
+		}
+	}()
+
+	r := &http.Request{
+		Method: http.MethodConnect,
+		URL:    &url.URL{Host: addr},
+		Header: map[string][]string{"User-Agent": {"micro/latest"}},
+	}
+
+	if user := proxyURL.User; user != nil {
+		u := user.Username()
+		p, _ := user.Password()
+		auth := []byte(u + ":" + p)
+		basicAuth := base64.StdEncoding.EncodeToString(auth)
+		r.Header.Add(proxyAuthHeader, "Basic "+basicAuth)
+	}
+
+	if err := r.Write(conn); err != nil {
+		return nil, fmt.Errorf("failed to write the HTTP request: %v", err)
+	}
+
+	br := bufio.NewReader(conn)
+	rsp, err := http.ReadResponse(br, r)
+	if err != nil {
+		return nil, fmt.Errorf("reading server HTTP response: %v", err)
+	}
+	defer rsp.Body.Close()
+	if rsp.StatusCode != http.StatusOK {
+		dump, err := httputil.DumpResponse(rsp, true)
+		if err != nil {
+			return nil, fmt.Errorf("failed to do connect handshake, status code: %s", rsp.Status)
+		}
+		return nil, fmt.Errorf("failed to do connect handshake, response: %q", dump)
+	}
+
+	return &pbuffer{Conn: conn, r: br}, nil
+}
+
+// Creates a new connection
+func newConn(dial func(string) (net.Conn, error)) func(string) (net.Conn, error) {
+	return func(addr string) (net.Conn, error) {
+		// get the proxy url
+		proxyURL, err := getURL(addr)
+		if err != nil {
+			return nil, err
+		}
+
+		// set to addr
+		callAddr := addr
+
+		// got proxy
+		if proxyURL != nil {
+			callAddr = proxyURL.Host
+		}
+
+		// dial the addr
+		c, err := dial(callAddr)
+		if err != nil {
+			return nil, err
+		}
+
+		// do proxy connect if we have proxy url
+		if proxyURL != nil {
+			c, err = proxyDial(c, addr, proxyURL)
+		}
+
+		return c, err
+	}
+}

transport/http_transport.go

@@ -452,9 +452,13 @@ func (h *httpTransport) Dial(addr string, opts ...DialOption) (Client, error) {
 				InsecureSkipVerify: true,
 			}
 		}
-		conn, err = tls.DialWithDialer(&net.Dialer{Timeout: dopts.Timeout}, "tcp", addr, config)
+		conn, err = newConn(func(addr string) (net.Conn, error) {
+			return tls.DialWithDialer(&net.Dialer{Timeout: dopts.Timeout}, "tcp", addr, config)
+		})(addr)
 	} else {
-		conn, err = net.DialTimeout("tcp", addr, dopts.Timeout)
+		conn, err = newConn(func(addr string) (net.Conn, error) {
+			return net.DialTimeout("tcp", addr, dopts.Timeout)
+		})(addr)
 	}
 
 	if err != nil {