]> git.scottworley.com Git - reliable-chat/blame_incremental - server/server.go
This 'form' is never submitted.
[reliable-chat] / server / server.go
... / ...
CommitLineData
1package main
2
3import "container/list"
4import "encoding/json"
5import "expvar"
6import "flag"
7import "log"
8import "net/http"
9import "strconv"
10import "time"
11
12var port = flag.Int("port", 21059, "Port to listen on")
13
14var speak_count = expvar.NewInt("speak_count")
15var fetch_count = expvar.NewInt("fetch_count")
16var fetch_wait_count = expvar.NewInt("fetch_wait_count")
17var fetch_wake_count = expvar.NewInt("fetch_wake_count")
18
19type Message struct {
20 Time time.Time
21 ID string
22 Text string
23}
24
25type StoreRequest struct {
26 StartTime time.Time
27 Messages chan<- []Message
28}
29
30type Store struct {
31 Add chan *Message
32 Get chan *StoreRequest
33}
34
35// TODO: Monotonic clock
36
37func manage_store(store Store) {
38 messages := list.New()
39 message_count := 0
40 max_messages := 1000
41 waiting := list.New()
42main:
43 for {
44 select {
45 case new_message, ok := <-store.Add:
46 if !ok {
47 break main
48 }
49 speak_count.Add(1)
50 for waiter := waiting.Front(); waiter != nil; waiter = waiter.Next() {
51 waiter.Value.(*StoreRequest).Messages <- []Message{*new_message}
52 close(waiter.Value.(*StoreRequest).Messages)
53 fetch_wake_count.Add(1)
54 }
55 waiting.Init()
56 messages.PushBack(new_message)
57 if message_count < max_messages {
58 message_count++
59 } else {
60 messages.Remove(messages.Front())
61 }
62 case request, ok := <-store.Get:
63 if !ok {
64 break main
65 }
66 fetch_count.Add(1)
67 if messages.Back() == nil || !request.StartTime.Before(messages.Back().Value.(*Message).Time) {
68 waiting.PushBack(request)
69 fetch_wait_count.Add(1)
70 } else {
71 start := messages.Back()
72 response_size := 1
73 if messages.Front().Value.(*Message).Time.After(request.StartTime) {
74 start = messages.Front()
75 response_size = message_count
76 } else {
77 for start.Prev().Value.(*Message).Time.After(request.StartTime) {
78 start = start.Prev()
79 response_size++
80 }
81 }
82 response_messages := make([]Message, 0, response_size)
83 for m := start; m != nil; m = m.Next() {
84 response_messages = append(response_messages, *m.Value.(*Message))
85 }
86 request.Messages <- response_messages
87 }
88 }
89 }
90}
91
92func start_store() Store {
93 store := Store{make(chan *Message, 20), make(chan *StoreRequest, 20)}
94 go manage_store(store)
95 return store
96}
97
98func start_server(store Store) {
99 http.HandleFunc("/fetch", func(w http.ResponseWriter, r *http.Request) {
100 var since time.Time
101 url_since := r.FormValue("since")
102 if url_since != "" {
103 err := json.Unmarshal([]byte(url_since), &since)
104 if err != nil {
105 log.Print("fetch: parse since: ", err)
106 w.WriteHeader(http.StatusBadRequest)
107 w.Write([]byte("Could not parse since as date"))
108 return
109 }
110 }
111 messages_from_store := make(chan []Message, 1)
112 store.Get <- &StoreRequest{since, messages_from_store}
113
114 json_encoded, err := json.Marshal(<-messages_from_store)
115 if err != nil {
116 log.Print("json encode: ", err)
117 w.WriteHeader(http.StatusInternalServerError)
118 return
119 }
120 w.Header().Add("Content-Type", "application/json")
121 w.Write(json_encoded)
122 })
123
124 http.HandleFunc("/speak", func(w http.ResponseWriter, r *http.Request) {
125 store.Add <- &Message{
126 time.Now(),
127 r.FormValue("id"),
128 r.FormValue("text")}
129 })
130
131 log.Fatal(http.ListenAndServe(":"+strconv.Itoa(*port), nil))
132}
133
134func main() {
135 store := start_store()
136 start_server(store)
137}