From: Scott Worley Date: Sat, 28 Jul 2012 05:45:54 +0000 (-0700) Subject: First cut at minimum-functionality server X-Git-Url: http://git.scottworley.com/reliable-chat/commitdiff_plain/92d1d6ac689a422fcf43dec8f5a081aa09f05ae5?ds=sidebyside First cut at minimum-functionality server --- 92d1d6ac689a422fcf43dec8f5a081aa09f05ae5 diff --git a/server/server.go b/server/server.go new file mode 100644 index 0000000..a8b1c53 --- /dev/null +++ b/server/server.go @@ -0,0 +1,108 @@ +package main + +import "container/list" +import "encoding/json" +import "log" +import "net/http" +import "time" + +type Message struct { + Time time.Time + 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 +} + +// TODO: Monotonic clock + +func manage_store(store Store) { + messages := list.New() + message_count := 0 + max_messages := 1000 + waiting := list.New() + for { + select { + case new_message := <-store.Add: + messages.PushBack(new_message) + for waiter := waiting.Front(); waiter != nil; waiter = waiter.Next() { + waiter.Value.(StoreRequest).Messages <- []Message{new_message} + close(waiter.Value.(StoreRequest).Messages) + } + waiting.Init() + 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) { + waiting.PushBack(request) + } else { + start := messages.Back() + response_size := 1 + 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) { + 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)) + } + request.Messages <- response_messages + } + } + } +} + +func start_store() Store { + store := Store{make(chan Message, 20), make(chan StoreRequest, 20)} + go manage_store(store) + return store +} + +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 + messages_from_store := make(chan []Message, 1) + store.Get <- StoreRequest{since, messages_from_store} + + json_encoded, err := json.Marshal(FetchResponse{<-messages_from_store, time.Now()}) + if err != nil { + log.Print("json encode: ", err) + w.WriteHeader(http.StatusInternalServerError) + return + } + w.Header().Add("Content-Type", "application/json") + w.Write(json_encoded) + }) + + http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) { + text := "woof" // TODO: Get text from URL + store.Add <- Message{time.Now(), text} + }) + + log.Fatal(http.ListenAndServe(":8080", nil)) +} + +func main() { + store := start_store() + start_server(store) +}