import "container/list"
import "encoding/json"
+import "expvar"
+import "flag"
import "log"
import "net/http"
+import "strconv"
import "time"
+var port = flag.Int("port", 21059, "Port to listen on")
+
+var speak_count = expvar.NewInt("speak_count")
+var fetch_count = expvar.NewInt("fetch_count")
+var fetch_wait_count = expvar.NewInt("fetch_wait_count")
+var fetch_wake_count = expvar.NewInt("fetch_wake_count")
+
type Message struct {
Time time.Time
+ ID string
Text string
}
-type FetchResponse struct {
- Messages []Message
- Time time.Time
-}
-
type StoreRequest struct {
StartTime time.Time
Messages chan<- []Message
}
type Store struct {
- Add chan Message
- Get chan StoreRequest
+ Add chan *Message
+ Get chan *StoreRequest
}
// TODO: Monotonic clock
message_count := 0
max_messages := 1000
waiting := list.New()
+main:
for {
select {
- case new_message := <-store.Add:
- messages.PushBack(new_message)
+ case new_message, ok := <-store.Add:
+ if !ok {
+ break main
+ }
+ speak_count.Add(1)
for waiter := waiting.Front(); waiter != nil; waiter = waiter.Next() {
- waiter.Value.(StoreRequest).Messages <- []Message{new_message}
- close(waiter.Value.(StoreRequest).Messages)
+ waiter.Value.(*StoreRequest).Messages <- []Message{*new_message}
+ close(waiter.Value.(*StoreRequest).Messages)
+ fetch_wake_count.Add(1)
}
waiting.Init()
+ messages.PushBack(new_message)
if message_count < max_messages {
message_count++
} else {
messages.Remove(messages.Front())
}
- case request := <-store.Get:
- if messages.Back() == nil || request.StartTime.After(messages.Back().Value.(Message).Time) {
+ case request, ok := <-store.Get:
+ if !ok {
+ break main
+ }
+ fetch_count.Add(1)
+ if messages.Back() == nil || !request.StartTime.Before(messages.Back().Value.(*Message).Time) {
waiting.PushBack(request)
+ fetch_wait_count.Add(1)
} else {
start := messages.Back()
response_size := 1
- if messages.Front().Value.(Message).Time.After(request.StartTime) {
+ if messages.Front().Value.(*Message).Time.After(request.StartTime) {
start = messages.Front()
response_size = message_count
} else {
- for start.Prev().Value.(Message).Time.After(request.StartTime) {
+ for start.Prev().Value.(*Message).Time.After(request.StartTime) {
start = start.Prev()
response_size++
}
}
response_messages := make([]Message, 0, response_size)
for m := start; m != nil; m = m.Next() {
- response_messages = append(response_messages, m.Value.(Message))
+ response_messages = append(response_messages, *m.Value.(*Message))
}
request.Messages <- response_messages
}
}
func start_store() Store {
- store := Store{make(chan Message, 20), make(chan StoreRequest, 20)}
+ store := Store{make(chan *Message, 20), make(chan *StoreRequest, 20)}
go manage_store(store)
return store
}
+const frame_html = `<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
+ "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
+
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+ <script type="text/javascript"><!--//--><![CDATA[//><!--
+ var since;
+ function go() {
+ var delay = 10000;
+ var xhr = new XMLHttpRequest();
+ xhr.onreadystatechange = function() {
+ if (this.readyState == this.DONE) {
+ if (this.status == 200) {
+ var rtxt = this.responseText;
+ if (rtxt != null) {
+ var r = JSON.parse(rtxt);
+ if (r != null) {
+ window.parent.postMessage(rtxt, "*");
+ delay = 40;
+ if (r.length >= 1 && "Time" in r[r.length-1]) {
+ since = r[r.length-1]["Time"];
+ }
+ }
+ }
+ }
+ window.setTimeout(go, delay);
+ }
+ }
+ var uri = "/fetch";
+ if (since) {
+ uri += '?since="' + since + '"';
+ }
+ xhr.open("GET", uri);
+ xhr.send();
+ }
+ //--><!]]></script>
+</head>
+<body onload="go()">
+</body>
+</html>
+`
+
func start_server(store Store) {
http.HandleFunc("/fetch", func(w http.ResponseWriter, r *http.Request) {
- var since time.Time // TODO: Get start time from URL
+ var since time.Time
+ url_since := r.FormValue("since")
+ if url_since != "" {
+ err := json.Unmarshal([]byte(url_since), &since)
+ if err != nil {
+ log.Print("fetch: parse since: ", err)
+ w.WriteHeader(http.StatusBadRequest)
+ w.Write([]byte("Could not parse since as date"))
+ return
+ }
+ }
messages_from_store := make(chan []Message, 1)
- store.Get <- StoreRequest{since, messages_from_store}
+ store.Get <- &StoreRequest{since, messages_from_store}
- json_encoded, err := json.Marshal(FetchResponse{<-messages_from_store, time.Now()})
+ json_encoded, err := json.Marshal(<-messages_from_store)
if err != nil {
log.Print("json encode: ", err)
w.WriteHeader(http.StatusInternalServerError)
})
http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) {
- text := "woof" // TODO: Get text from URL
- store.Add <- Message{time.Now(), text}
+ store.Add <- &Message{
+ time.Now(),
+ r.FormValue("id"),
+ r.FormValue("text")}
+ })
+
+ http.HandleFunc("/frame", func(w http.ResponseWriter, r *http.Request) {
+ w.Write([]byte(frame_html));
})
- log.Fatal(http.ListenAndServe(":8080", nil))
+ log.Fatal(http.ListenAndServe(":"+strconv.Itoa(*port), nil))
}
func main() {
projects / reliable-chat / blobdiff