/speak requests are permitted cross-origin

[reliable-chat] / server / server.go

diff --git a/server/server.go b/server/server.go
index 74a1da2cfc483488cbd94fb696712db8dfb1ae89..963931f696d759459f6cb90512cd796100f88fcb 100644 (file)
--- a/server/server.go
+++ b/server/server.go
@@ -30,10 +30,12 @@ var port = flag.Int("port", 21059, "Port to listen on")
 var localaddress = flag.String("localaddress", "", "Local address to bind to")
 var max_messages = flag.Int("maxmessages", 1000, "Maximum number of messages to retain")
 
+var start_time = expvar.NewInt("start_time")
 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")
+var drop_due_to_limit_count = expvar.NewInt("drop_due_to_limit_count")
 
 type Message struct {
        Time time.Time
@@ -51,7 +53,39 @@ type Store struct {
        Get chan *StoreRequest
 }
 
-// TODO: Monotonic clock
+var monotonic_clock chan chan time.Time
+
+const minimum_clock_increment = time.Millisecond
+
+func start_clock() {
+       internal_monotonic_clock := make(chan chan time.Time, 1)
+       go func() {
+               last_time := time.Now()
+       main:
+               for {
+                       select {
+                       case request, ok := <-internal_monotonic_clock:
+                               if !ok {
+                                       break main
+                               }
+                               earliest_acceptable_time := last_time.Add(minimum_clock_increment)
+                               current_time := time.Now()
+                               if current_time.Before(earliest_acceptable_time) {
+                                       current_time = earliest_acceptable_time
+                               }
+                               request <- current_time
+                               last_time = current_time
+                       }
+               }
+       }()
+       monotonic_clock = internal_monotonic_clock
+}
+
+func now() time.Time {
+       c := make(chan time.Time, 0)
+       monotonic_clock <- c
+       return <-c
+}
 
 func manage_store(store Store) {
        messages := list.New()
@@ -76,6 +110,7 @@ main:
                                message_count++
                        } else {
                                messages.Remove(messages.Front())
+                               drop_due_to_limit_count.Add(1)
                        }
                case request, ok := <-store.Get:
                        if !ok {
@@ -146,13 +181,14 @@ func start_server(store Store) {
 
        http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) {
                store.Add <- &Message{
-                       time.Now(),
+                       now(),
                        r.FormValue("id"),
                        r.FormValue("text")}
+               w.Header().Add("Access-Control-Allow-Origin", "*")
        })
 
        http.HandleFunc("/robots.txt", func(w http.ResponseWriter, r *http.Request) {
-               w.Write([]byte(robots_txt));
+               w.Write([]byte(robots_txt))
        })
 
        log.Fatal(http.ListenAndServe(*localaddress+":"+strconv.Itoa(*port), nil))
@@ -160,6 +196,8 @@ func start_server(store Store) {
 
 func main() {
        flag.Parse()
+       start_clock()
+       start_time.Set(now().UnixNano())
        store := start_store()
        start_server(store)
 }