// handle receives messages on the given websocket connection, decoding them
// from JSON to a Msg object. It adds a channel to listeners, encoding messages
// received on the listener channel as JSON, then sending it over the connection.
func (r *Router) HandleWebsocket(c *websocket.Conn) {
u, err := url.Parse(c.LocalAddr().String())
if err != nil {
log.Println(err)
return
}
// split url path into components, e.g.
// url: http://leeps.ucsc.edu/redwood/session/1/[email protected]
// path: /redwood/session/1/[email protected]
// -> [redwood, session, 1, [email protected]]
components := strings.Split(u.Path, "/")
// map components into instance_prefix, session_id, and subject_name
var instance, session_id_string, subject_name string
if len(components) >= 4 {
instance = components[1]
session_id_string = components[2]
subject_name = components[3]
} else {
session_id_string = components[1]
subject_name = components[2]
}
session_id, err := strconv.Atoi(session_id_string)
if err != nil {
log.Println(err)
return
}
var subject *Subject
if subject_name == "admin" || subject_name == "listener" {
subject = &Subject{name: subject_name, period: -1, group: -1}
} else {
// put in a request to the server loop for the given subject object
// this ensures only one subject object exists per session/name pair
request := &SubjectRequest{instance: instance, session: session_id, name: subject_name, response: make(chan *Subject)}
r.requestSubject <- request
subject = <-request.response
}
if subject == nil {
log.Panicln("nil subject")
}
listener := NewListener(r, instance, session_id, subject, c)
ack := make(chan bool)
r.newListeners <- &ListenerRequest{listener, ack}
// wait for listener to be registered before starting sync
<-ack
log.Printf("STARTED SYNC: %s\n", subject.name)
listener.Sync()
log.Printf("FINISHED SYNC: %s\n", subject.name)
go listener.SendLoop()
listener.ReceiveLoop()
}