Better visibility for the server status indicators

[reliable-chat] / server / server.go

diff --git a/server/server.go b/server/server.go
index 8c8a9893d61360dd00f3ea643871fe7fb33339d2..5c5ef50fbfd448989c3b57648f466e76ede087fa 100644 (file)
--- a/server/server.go
+++ b/server/server.go
@@ -2,28 +2,34 @@ package main
 
 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
@@ -33,38 +39,49 @@ func manage_store(store Store) {
        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
                        }
@@ -73,11 +90,53 @@ func manage_store(store Store) {
 }
 
 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
@@ -92,9 +151,9 @@ func start_server(store Store) {
                        }
                }
                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)
@@ -105,10 +164,17 @@ func start_server(store Store) {
        })
 
        http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) {
-               store.Add <- Message{time.Now(), r.FormValue("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() {