Implement permissive STUN URL parsing

The parser included in the ice package strictly adheres to RFC 7064,
however, this can be problematic when attempting to use ICE server URLs
that were automatically generated by a third party.

Twilio, for example, has been seen to send the following in its list of
ICE servers:

    stun:global.stun.twilio.com:3478?transport=udp

which would require user intervention to sanitise before passing to
Pion.
This patch side-steps this aspect of ice.ParseURL by pre-stripping any
queries that may be present so that we can allow URLs of this form.

configuration.go

@@ -2,10 +2,6 @@
 
 package webrtc
 
-import (
-	"github.com/pion/ice"
-)
-
 // Configuration defines a set of parameters to configure how the
 // peer-to-peer communication via PeerConnection is established or
 // re-established.
@@ -51,17 +47,3 @@ type Configuration struct {
 	// SDP answers generated by the PeerConnection.
 	SDPSemantics SDPSemantics
 }
-
-func (c Configuration) getICEServers() (*[]*ice.URL, error) {
-	var iceServers []*ice.URL
-	for _, server := range c.ICEServers {
-		for _, rawURL := range server.URLs {
-			url, err := ice.ParseURL(rawURL)
-			if err != nil {
-				return nil, err
-			}
-			iceServers = append(iceServers, url)
-		}
-	}
-	return &iceServers, nil
-}

configuration_common.go

@@ -0,0 +1,29 @@
+package webrtc
+
+import (
+	"strings"
+
+	"github.com/pion/ice"
+)
+
+// getICEServers side-steps the strict parsing mode of the ice package
+// (as defined in https://tools.ietf.org/html/rfc7064) by stripping any
+// erroneous queries from "stun(s):" URLs before parsing.
+func (c Configuration) getICEServers() (*[]*ice.URL, error) {
+	var iceServers []*ice.URL
+	for _, server := range c.ICEServers {
+		for _, rawURL := range server.URLs {
+			if strings.HasPrefix(rawURL, "stun") {
+				// strip the query from "stun(s):" if present
+				parts := strings.Split(rawURL, "?")
+				rawURL = parts[0]
+			}
+			url, err := ice.ParseURL(rawURL)
+			if err != nil {
+				return nil, err
+			}
+			iceServers = append(iceServers, url)
+		}
+	}
+	return &iceServers, nil
+}

configuration_js.go

@@ -2,10 +2,6 @@
 
 package webrtc
 
-import (
-	"github.com/pion/ice"
-)
-
 // Configuration defines a set of parameters to configure how the
 // peer-to-peer communication via PeerConnection is established or
 // re-established.
@@ -37,17 +33,3 @@ type Configuration struct {
 	// ICECandidatePoolSize describes the size of the prefetched ICE pool.
 	ICECandidatePoolSize uint8
 }
-
-func (c Configuration) getICEServers() (*[]*ice.URL, error) {
-	var iceServers []*ice.URL
-	for _, server := range c.ICEServers {
-		for _, rawURL := range server.URLs {
-			url, err := ice.ParseURL(rawURL)
-			if err != nil {
-				return nil, err
-			}
-			iceServers = append(iceServers, url)
-		}
-	}
-	return &iceServers, nil
-}

configuration_test.go

@@ -35,4 +35,21 @@ func TestConfiguration_getICEServers(t *testing.T) {
 		_, err := cfg.getICEServers()
 		assert.NotNil(t, err)
 	})
+
+	t.Run("Success", func(t *testing.T) {
+		// ignore the fact that stun URLs shouldn't have a query
+		serverStr := "stun:global.stun.twilio.com:3478?transport=udp"
+		expectedServerStr := "stun:global.stun.twilio.com:3478"
+		cfg := Configuration{
+			ICEServers: []ICEServer{
+				{
+					URLs: []string{serverStr},
+				},
+			},
+		}
+
+		parsedURLs, err := cfg.getICEServers()
+		assert.Nil(t, err)
+		assert.Equal(t, expectedServerStr, (*parsedURLs)[0].String())
+	})
 }