Add UUID4 func and use it instead of hard-coded <iq/> ids.

client.go

@@ -52,7 +52,7 @@ func main() {
 
 	// Get disco#info for home server.
 	info := &DiscoInfo{}
-	iq := xmpp.Iq{Id: "abc", Type: "get", To: x.JID.Domain}
+	iq := xmpp.Iq{Id: xmpp.UUID4(), Type: "get", To: x.JID.Domain}
 	iq.PayloadEncode(info)
 	reply, _ := x.SendRecv(&iq)
 	reply.PayloadDecode(info)

src/xmpp/client.go

@@ -180,7 +180,7 @@ type saslAuth struct {
 
 func bindResource(stream *Stream, jid JID) (JID, error) {
 
-	req := Iq{Id: "foo", Type: "set"}
+	req := Iq{Id: UUID4(), Type: "set"}
 	if jid.Resource == "" {
 		req.PayloadEncode(bindIq{})
 	} else {
@@ -245,5 +245,3 @@ type saslFailure struct {
 	XMLName xml.Name `xml:"urn:ietf:params:xml:ns:xmpp-sasl failure"`
 	Reason xml.Name `xml:",any"`
 }
-
-// BUG(matt): Don't use "foo" as the <iq/> id during resource binding.

src/xmpp/uuid.go

@@ -0,0 +1,18 @@
+package xmpp
+
+import (
+	"crypto/rand"
+	"fmt"
+)
+
+// Generate a UUID4.
+func UUID4() string {
+	uuid := make([]byte, 16)
+	if _, err := rand.Read(uuid); err != nil {
+		panic(err)
+	}
+	uuid[6] = (uuid[6] & 0x0F) | 0x40
+	uuid[8] = (uuid[8] &^ 0x40) | 0x80
+	return fmt.Sprintf("%x-%x-%x-%x-%x", uuid[:4], uuid[4:6], uuid[6:8], uuid[8:10], uuid[10:])
+}
+