s/MeekChannel/BrokerChannel (close #14) and more informative TODOs

client/rendezvous.go

@@ -0,0 +1,75 @@
+// WebRTC Rendezvous requires the exchange of SessionDescriptions between
+// peers. This file contains the domain-fronted HTTP signaling mechanism
+// between the client and a desired Broker.
+package main
+
+import (
+	"bytes"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/url"
+
+	"github.com/keroserene/go-webrtc"
+)
+
+// Signalling Channel to the Broker.
+type BrokerChannel struct {
+	// The Host header to put in the HTTP request (optional and may be
+	// different from the host name in URL).
+	Host      string
+	url       *url.URL
+	transport http.Transport // Used to make all requests.
+}
+
+// Construct a new BrokerChannel, where:
+// |broker| is the full URL of the facilitating program which assigns proxies
+// to clients, and |front| is the option fronting domain.
+func NewBrokerChannel(broker string, front string) *BrokerChannel {
+	targetURL, err := url.Parse(broker)
+	if nil != err {
+		return nil
+	}
+	bc := new(BrokerChannel)
+	bc.url = targetURL
+	if "" != front { // Optional front domain.
+		bc.Host = bc.url.Host
+		bc.url.Host = front
+	}
+
+	// We make a copy of DefaultTransport because we want the default Dial
+	// and TLSHandshakeTimeout settings. But we want to disable the default
+	// ProxyFromEnvironment setting.
+	bc.transport = *http.DefaultTransport.(*http.Transport)
+	bc.transport.Proxy = nil
+	return bc
+}
+
+// Roundtrip HTTP POST using WebRTC SessionDescriptions.
+//
+// Send an SDP offer to the broker, which assigns a proxy and responds
+// with an SDP answer from a designated remote WebRTC peer.
+func (bc *BrokerChannel) Negotiate(offer *webrtc.SessionDescription) (
+	*webrtc.SessionDescription, error) {
+	data := bytes.NewReader([]byte(offer.Serialize()))
+	// Suffix with broker's client registration handler.
+	request, err := http.NewRequest("POST", bc.url.String()+"client", data)
+	if nil != err {
+		return nil, err
+	}
+	if "" != bc.Host { // Set true host if necessary.
+		request.Host = bc.Host
+	}
+	resp, err := bc.transport.RoundTrip(request)
+	if nil != err {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	log.Printf("BrokerChannel Response:\n%s\n\n", resp.Status)
+	body, err := ioutil.ReadAll(resp.Body)
+	if nil != err {
+		return nil, err
+	}
+	answer := webrtc.DeserializeSessionDescription(string(body))
+	return answer, nil
+}