|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "bytes" |
| 5 | + "fmt" |
| 6 | + "log" |
| 7 | + "net/http" |
| 8 | + "time" |
| 9 | + |
| 10 | + "github.com/gorilla/websocket" |
| 11 | + "github.com/thanhpk/randstr" |
| 12 | +) |
| 13 | + |
| 14 | +var upgrader = websocket.Upgrader{ |
| 15 | + CheckOrigin: func(r *http.Request) bool { |
| 16 | + return true |
| 17 | + }, |
| 18 | +} |
| 19 | + |
| 20 | +type hub struct { |
| 21 | + clients map[*client]bool |
| 22 | + broadcast chan []byte |
| 23 | + register chan *client |
| 24 | + unregister chan *client |
| 25 | + exec chan string |
| 26 | + shutdown chan struct{} |
| 27 | +} |
| 28 | + |
| 29 | +type client struct { |
| 30 | + hub *hub |
| 31 | + conn *websocket.Conn |
| 32 | + send chan []byte |
| 33 | +} |
| 34 | + |
| 35 | +func newHub(exec chan string) *hub { |
| 36 | + return &hub{ |
| 37 | + broadcast: make(chan []byte), |
| 38 | + register: make(chan *client), |
| 39 | + unregister: make(chan *client), |
| 40 | + clients: make(map[*client]bool), |
| 41 | + exec: exec, |
| 42 | + shutdown: make(chan struct{}), |
| 43 | + } |
| 44 | +} |
| 45 | + |
| 46 | +func (h *hub) run() { |
| 47 | + for { |
| 48 | + select { |
| 49 | + case client := <-h.register: |
| 50 | + h.clients[client] = true |
| 51 | + case client := <-h.unregister: |
| 52 | + if _, ok := h.clients[client]; ok { |
| 53 | + delete(h.clients, client) |
| 54 | + close(client.send) |
| 55 | + } |
| 56 | + case message := <-h.broadcast: |
| 57 | + for client := range h.clients { |
| 58 | + select { |
| 59 | + case client.send <- message: |
| 60 | + default: |
| 61 | + close(client.send) |
| 62 | + delete(h.clients, client) |
| 63 | + } |
| 64 | + } |
| 65 | + case <-h.shutdown: |
| 66 | + for client := range h.clients { |
| 67 | + close(client.send) |
| 68 | + delete(h.clients, client) |
| 69 | + } |
| 70 | + } |
| 71 | + } |
| 72 | +} |
| 73 | + |
| 74 | +const ( |
| 75 | + writeWait = 10 * time.Second |
| 76 | + pongWait = 60 * time.Second |
| 77 | + pingPeriod = (pongWait * 9) / 10 |
| 78 | + maxMessageSize = 512 |
| 79 | +) |
| 80 | + |
| 81 | +var ( |
| 82 | + newline = []byte{'\n'} |
| 83 | + space = []byte{' '} |
| 84 | +) |
| 85 | + |
| 86 | +func (c *client) readPump() { |
| 87 | + defer func() { |
| 88 | + c.hub.unregister <- c |
| 89 | + c.conn.Close() |
| 90 | + }() |
| 91 | + c.conn.SetReadLimit(maxMessageSize) |
| 92 | + c.conn.SetReadDeadline(time.Now().Add(pongWait)) |
| 93 | + c.conn.SetPongHandler(func(string) error { c.conn.SetReadDeadline(time.Now().Add(pongWait)); return nil }) |
| 94 | + for { |
| 95 | + _, message, err := c.conn.ReadMessage() |
| 96 | + if err != nil { |
| 97 | + break |
| 98 | + } |
| 99 | + message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1)) |
| 100 | + c.hub.broadcast <- message |
| 101 | + c.hub.exec <- string(message) |
| 102 | + } |
| 103 | +} |
| 104 | + |
| 105 | +func (c *client) writePump() { |
| 106 | + ticker := time.NewTicker(pingPeriod) |
| 107 | + defer func() { |
| 108 | + ticker.Stop() |
| 109 | + c.conn.Close() |
| 110 | + }() |
| 111 | + for { |
| 112 | + select { |
| 113 | + case message, ok := <-c.send: |
| 114 | + c.conn.SetWriteDeadline(time.Now().Add(writeWait)) |
| 115 | + if !ok { |
| 116 | + c.conn.WriteMessage(websocket.CloseMessage, []byte{}) |
| 117 | + return |
| 118 | + } |
| 119 | + w, err := c.conn.NextWriter(websocket.TextMessage) |
| 120 | + if err != nil { |
| 121 | + return |
| 122 | + } |
| 123 | + w.Write(message) |
| 124 | + n := len(c.send) |
| 125 | + for i := 0; i < n; i++ { |
| 126 | + w.Write(newline) |
| 127 | + w.Write(<-c.send) |
| 128 | + } |
| 129 | + if err := w.Close(); err != nil { |
| 130 | + return |
| 131 | + } |
| 132 | + case <-ticker.C: |
| 133 | + c.conn.SetWriteDeadline(time.Now().Add(writeWait)) |
| 134 | + if err := c.conn.WriteMessage(websocket.PingMessage, nil); err != nil { |
| 135 | + return |
| 136 | + } |
| 137 | + } |
| 138 | + } |
| 139 | +} |
| 140 | + |
| 141 | +func serveWs(hub *hub, w http.ResponseWriter, r *http.Request) { |
| 142 | + conn, err := upgrader.Upgrade(w, r, nil) |
| 143 | + if err != nil { |
| 144 | + log.Println(err) |
| 145 | + return |
| 146 | + } |
| 147 | + client := &client{hub: hub, conn: conn, send: make(chan []byte, 256)} |
| 148 | + client.hub.register <- client |
| 149 | + |
| 150 | + go client.writePump() |
| 151 | + go client.readPump() |
| 152 | +} |
| 153 | + |
| 154 | +func newWs(exec chan string, addr string, token string) (func(string), func()) { |
| 155 | + if addr == "" { |
| 156 | + return func(ignore string) {}, func() {} |
| 157 | + } |
| 158 | + printInfo("WebSocket Enabled.") |
| 159 | + realtoken := token |
| 160 | + if token == "" { |
| 161 | + realtoken := randstr.Hex(64) |
| 162 | + printPair("WebSocket Token", realtoken) |
| 163 | + } |
| 164 | + hub := newHub(exec) |
| 165 | + go hub.run() |
| 166 | + http.HandleFunc(fmt.Sprintf("/%s", realtoken), func(w http.ResponseWriter, r *http.Request) { |
| 167 | + serveWs(hub, w, r) |
| 168 | + }) |
| 169 | + srv := http.Server{Addr: addr} |
| 170 | + go srv.ListenAndServe() |
| 171 | + return func(out string) { |
| 172 | + hub.broadcast <- []byte(out) |
| 173 | + }, func() { |
| 174 | + srv.Shutdown(nil) |
| 175 | + hub.shutdown <- struct{}{} |
| 176 | + } |
| 177 | +} |
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