Polling API for the chat room

pkg/polling_api.go

@@ -0,0 +1,240 @@
+package barertc
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"time"
+
+	"git.kirsle.net/apps/barertc/pkg/log"
+	"git.kirsle.net/apps/barertc/pkg/messages"
+	"git.kirsle.net/apps/barertc/pkg/util"
+	"github.com/google/uuid"
+)
+
+// Polling user timeout before disconnecting them.
+const PollingUserTimeout = time.Minute
+
+// JSON payload structure for polling API.
+type PollMessage struct {
+	// Send the username after authenticated.
+	Username string `json:"username,omitempty"`
+
+	// SessionID for authentication.
+	SessionID string `json:"session_id,omitempty"`
+
+	// BareRTC protocol message.
+	Message messages.Message `json:"msg"`
+}
+
+type PollResponse struct {
+	// Session ID.
+	Username  string `json:"username,omitempty"`
+	SessionID string `json:"session_id,omitempty"`
+
+	// Pending messages.
+	Messages []messages.Message `json:"messages"`
+}
+
+// Helper method to send an error as a PollResponse.
+func PollResponseError(message string) PollResponse {
+	return PollResponse{
+		Messages: []messages.Message{
+			{
+				Action:   messages.ActionError,
+				Username: "ChatServer",
+				Message:  message,
+			},
+		},
+	}
+}
+
+// KickIdlePollUsers is a goroutine that will disconnect polling API users
+// who haven't been seen in a while.
+func (s *Server) KickIdlePollUsers() {
+	log.Debug("KickIdlePollUsers goroutine engaged")
+	for {
+		time.Sleep(10 * time.Second)
+		for _, sub := range s.IterSubscribers() {
+			if sub.usePolling && time.Since(sub.lastPollAt) > PollingUserTimeout {
+				// Send an exit message.
+				if sub.authenticated && sub.ChatStatus != "hidden" {
+					log.Error("KickIdlePollUsers: %s last seen %s ago", sub.Username, sub.lastPollAt)
+
+					sub.authenticated = false
+					s.Broadcast(messages.Message{
+						Action:   messages.ActionPresence,
+						Username: sub.Username,
+						Message:  "has timed out!",
+					})
+					s.SendWhoList()
+				}
+
+				s.DeleteSubscriber(sub)
+			}
+		}
+	}
+}
+
+// FlushPollResponse returns a response for the polling API that will flush
+// all pending messages sent to the client.
+func (sub *Subscriber) FlushPollResponse() PollResponse {
+	var msgs = []messages.Message{}
+
+	// Drain the messages from the outbox channel.
+	for len(sub.messages) > 0 {
+		message := <-sub.messages
+		var msg messages.Message
+		json.Unmarshal(message, &msg)
+		msgs = append(msgs, msg)
+	}
+
+	return PollResponse{
+		Username:  sub.Username,
+		SessionID: sub.sessionID,
+		Messages:  msgs,
+	}
+}
+
+// Functions for the Polling API as an alternative to WebSockets.
+func (s *Server) PollingAPI() http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ip := util.IPAddress(r)
+
+		// JSON writer for the response.
+		w.Header().Set("Content-Type", "application/json")
+		enc := json.NewEncoder(w)
+		enc.SetIndent("", "  ")
+
+		// Parse the request.
+		if r.Method != http.MethodPost {
+			w.WriteHeader(http.StatusBadRequest)
+			enc.Encode(PollResponseError("Only POST methods allowed"))
+			return
+		} else if r.Header.Get("Content-Type") != "application/json" {
+			w.WriteHeader(http.StatusBadRequest)
+			enc.Encode(PollResponseError("Only application/json content-types allowed"))
+			return
+		}
+
+		defer r.Body.Close()
+
+		// Parse the request payload.
+		var (
+			params PollMessage
+			dec    = json.NewDecoder(r.Body)
+		)
+		if err := dec.Decode(&params); err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+			enc.Encode(PollResponseError(err.Error()))
+			return
+		}
+
+		// Debug logging.
+		log.Debug("Polling connection from %s - %s", ip, r.Header.Get("User-Agent"))
+
+		// Are they resuming an authenticated session?
+		var sub *Subscriber
+		if params.Username != "" || params.SessionID != "" {
+			if params.Username == "" || params.SessionID == "" {
+				w.WriteHeader(http.StatusBadRequest)
+				enc.Encode(PollResponseError("Authentication error: SessionID and Username both required."))
+				return
+			}
+
+			log.Debug("Polling API: check if %s (%s) is authenticated", params.Username, params.SessionID)
+
+			// Look up the subscriber.
+			var (
+				authOK bool
+				err    error
+			)
+			sub, err = s.GetSubscriber(params.Username)
+			if err == nil {
+				// Validate the SessionID.
+				if sub.sessionID == params.SessionID {
+					authOK = true
+				}
+			}
+
+			// Authentication error.
+			if !authOK {
+				s.DeleteSubscriber(sub)
+				w.WriteHeader(http.StatusBadRequest)
+				enc.Encode(PollResponse{
+					Messages: []messages.Message{
+						{
+							Action:   messages.ActionError,
+							Username: "ChatServer",
+							Message:  "Your authentication has expired, please log back into the chat again.",
+						},
+						{
+							Action: messages.ActionKick,
+						},
+					},
+				})
+				return
+			}
+
+			// Ping their last seen time.
+			sub.lastPollAt = time.Now()
+		}
+
+		// If they are authenticated, handle this message.
+		if sub != nil && sub.authenticated {
+			s.OnClientMessage(sub, params.Message)
+
+			// If they use JWT authentication, give them a ping back with an updated
+			// JWT once in a while. Equivalent to the WebSockets pinger channel.
+			if time.Since(sub.lastPollJWT) > PingInterval {
+				sub.lastPollJWT = time.Now()
+
+				if sub.JWTClaims != nil {
+					if jwt, err := sub.JWTClaims.ReSign(); err != nil {
+						log.Error("ReSign JWT token for %s#%d: %s", sub.Username, sub.ID, err)
+					} else {
+						sub.SendJSON(messages.Message{
+							Action:   messages.ActionPing,
+							JWTToken: jwt,
+						})
+					}
+				}
+			}
+
+			enc.Encode(sub.FlushPollResponse())
+			return
+		}
+
+		// Not authenticated: the only acceptable message is login.
+		if params.Message.Action != messages.ActionLogin {
+			w.WriteHeader(http.StatusBadRequest)
+			enc.Encode(PollResponseError("Not logged in."))
+			return
+		}
+
+		// Prepare a Subscriber object for them. Do not add it to the server
+		// roster unless their login succeeds.
+		ctx, cancel := context.WithCancel(r.Context())
+		sub = s.NewPollingSubscriber(ctx, cancel)
+
+		// Tentatively add them to the server. If they don't pass authentication,
+		// remove their subscriber immediately. Note: they need added here so they
+		// will receive their own "has entered the room" and WhoList updates.
+		s.AddSubscriber(sub)
+
+		s.OnLogin(sub, params.Message)
+
+		// Are they authenticated?
+		if sub.authenticated {
+			// Generate a SessionID number.
+			sessionID := uuid.New().String()
+			sub.sessionID = sessionID
+
+			log.Debug("Polling API: new user authenticated in: %s (sid %s)", sub.Username, sub.sessionID)
+		} else {
+			s.DeleteSubscriber(sub)
+		}
+
+		enc.Encode(sub.FlushPollResponse())
+	})
+}

pkg/server.go

@@ -38,6 +38,7 @@ func (s *Server) Setup() error {
 	mux.Handle("/about", AboutPage())
 	mux.Handle("/logout", LogoutPage())
 	mux.Handle("/ws", s.WebSocket())
+	mux.Handle("/poll", s.PollingAPI())
 	mux.Handle("/api/statistics", s.Statistics())
 	mux.Handle("/api/blocklist", s.BlockList())
 	mux.Handle("/api/block/now", s.BlockNow())
@@ -54,5 +55,7 @@ func (s *Server) Setup() error {
 
 // ListenAndServe starts the web server.
 func (s *Server) ListenAndServe(address string) error {
+	// Run the polling user idle kicker.
+	go s.KickIdlePollUsers()
 	return http.ListenAndServe(address, s.mux)
 }

pkg/websocket.go

@@ -31,11 +31,19 @@ type Subscriber struct {
 	JWTClaims     *jwt.Claims
 	authenticated bool // has passed the login step
 	loginAt       time.Time
-	conn          *websocket.Conn
+
-	ctx           context.Context
+	// Connection details (WebSocket).
-	cancel        context.CancelFunc
+	conn      *websocket.Conn // WebSocket user
-	messages      chan []byte
+	ctx       context.Context
-	closeSlow     func()
+	cancel    context.CancelFunc
+	messages  chan []byte
+	closeSlow func()
+
+	// Polling API users.
+	usePolling  bool
+	sessionID   string
+	lastPollAt  time.Time
+	lastPollJWT time.Time // give a new JWT once in a while
 
 	muteMu  sync.RWMutex
 	booted  map[string]struct{} // usernames booted off your camera
@@ -51,6 +59,100 @@ type Subscriber struct {
 	logfh map[string]io.WriteCloser
 }
 
+// NewSubscriber initializes a connected chat user.
+func (s *Server) NewSubscriber(ctx context.Context, cancelFunc func()) *Subscriber {
+	return &Subscriber{
+		ctx:        ctx,
+		cancel:     cancelFunc,
+		messages:   make(chan []byte, s.subscriberMessageBuffer),
+		booted:     make(map[string]struct{}),
+		muted:      make(map[string]struct{}),
+		blocked:    make(map[string]struct{}),
+		messageIDs: make(map[int64]struct{}),
+		ChatStatus: "online",
+	}
+}
+
+// NewWebSocketSubscriber returns a new subscriber with a WebSocket connection.
+func (s *Server) NewWebSocketSubscriber(ctx context.Context, conn *websocket.Conn, cancelFunc func()) *Subscriber {
+	sub := s.NewSubscriber(ctx, cancelFunc)
+	sub.conn = conn
+	sub.closeSlow = func() {
+		conn.Close(websocket.StatusPolicyViolation, "connection too slow to keep up with messages")
+	}
+	return sub
+}
+
+// NewPollingSubscriber returns a new subscriber using the polling API.
+func (s *Server) NewPollingSubscriber(ctx context.Context, cancelFunc func()) *Subscriber {
+	sub := s.NewSubscriber(ctx, cancelFunc)
+	sub.usePolling = true
+	sub.lastPollAt = time.Now()
+	sub.lastPollJWT = time.Now()
+	sub.closeSlow = func() {
+		// Their outbox is filled up, disconnect them.
+		log.Error("Polling subscriber %s#%d: inbox is filled up!", sub.Username, sub.ID)
+
+		// Send an exit message.
+		if sub.authenticated && sub.ChatStatus != "hidden" {
+			sub.authenticated = false
+			s.Broadcast(messages.Message{
+				Action:   messages.ActionPresence,
+				Username: sub.Username,
+				Message:  "has exited the room!",
+			})
+			s.SendWhoList()
+		}
+
+		s.DeleteSubscriber(sub)
+	}
+	return sub
+}
+
+// OnClientMessage handles a chat protocol message from the user's WebSocket or polling API.
+func (s *Server) OnClientMessage(sub *Subscriber, msg messages.Message) {
+	// What action are they performing?
+	switch msg.Action {
+	case messages.ActionLogin:
+		s.OnLogin(sub, msg)
+	case messages.ActionMessage:
+		s.OnMessage(sub, msg)
+	case messages.ActionFile:
+		s.OnFile(sub, msg)
+	case messages.ActionMe:
+		s.OnMe(sub, msg)
+	case messages.ActionOpen:
+		s.OnOpen(sub, msg)
+	case messages.ActionBoot:
+		s.OnBoot(sub, msg, true)
+	case messages.ActionUnboot:
+		s.OnBoot(sub, msg, false)
+	case messages.ActionMute, messages.ActionUnmute:
+		s.OnMute(sub, msg, msg.Action == messages.ActionMute)
+	case messages.ActionBlock:
+		s.OnBlock(sub, msg)
+	case messages.ActionBlocklist:
+		s.OnBlocklist(sub, msg)
+	case messages.ActionCandidate:
+		s.OnCandidate(sub, msg)
+	case messages.ActionSDP:
+		s.OnSDP(sub, msg)
+	case messages.ActionWatch:
+		s.OnWatch(sub, msg)
+	case messages.ActionUnwatch:
+		s.OnUnwatch(sub, msg)
+	case messages.ActionTakeback:
+		s.OnTakeback(sub, msg)
+	case messages.ActionReact:
+		s.OnReact(sub, msg)
+	case messages.ActionReport:
+		s.OnReport(sub, msg)
+	case messages.ActionPing:
+	default:
+		sub.ChatServer("Unsupported message type.")
+	}
+}
+
 // ReadLoop spawns a goroutine that reads from the websocket connection.
 func (sub *Subscriber) ReadLoop(s *Server) {
 	go func() {
@@ -88,45 +190,8 @@ func (sub *Subscriber) ReadLoop(s *Server) {
 				log.Debug("Read(%d=%s): %s", sub.ID, sub.Username, data)
 			}
 
-			// What action are they performing?
+			// Handle their message.
-			switch msg.Action {
+			s.OnClientMessage(sub, msg)
-			case messages.ActionLogin:
-				s.OnLogin(sub, msg)
-			case messages.ActionMessage:
-				s.OnMessage(sub, msg)
-			case messages.ActionFile:
-				s.OnFile(sub, msg)
-			case messages.ActionMe:
-				s.OnMe(sub, msg)
-			case messages.ActionOpen:
-				s.OnOpen(sub, msg)
-			case messages.ActionBoot:
-				s.OnBoot(sub, msg, true)
-			case messages.ActionUnboot:
-				s.OnBoot(sub, msg, false)
-			case messages.ActionMute, messages.ActionUnmute:
-				s.OnMute(sub, msg, msg.Action == messages.ActionMute)
-			case messages.ActionBlock:
-				s.OnBlock(sub, msg)
-			case messages.ActionBlocklist:
-				s.OnBlocklist(sub, msg)
-			case messages.ActionCandidate:
-				s.OnCandidate(sub, msg)
-			case messages.ActionSDP:
-				s.OnSDP(sub, msg)
-			case messages.ActionWatch:
-				s.OnWatch(sub, msg)
-			case messages.ActionUnwatch:
-				s.OnUnwatch(sub, msg)
-			case messages.ActionTakeback:
-				s.OnTakeback(sub, msg)
-			case messages.ActionReact:
-				s.OnReact(sub, msg)
-			case messages.ActionReport:
-				s.OnReport(sub, msg)
-			default:
-				sub.ChatServer("Unsupported message type.")
-			}
 		}
 	}()
 }
@@ -202,20 +267,7 @@ func (s *Server) WebSocket() http.HandlerFunc {
 		// ctx := c.CloseRead(r.Context())
 		ctx, cancel := context.WithCancel(r.Context())
 
-		sub := &Subscriber{
+		sub := s.NewWebSocketSubscriber(ctx, c, cancel)
-			conn:     c,
-			ctx:      ctx,
-			cancel:   cancel,
-			messages: make(chan []byte, s.subscriberMessageBuffer),
-			closeSlow: func() {
-				c.Close(websocket.StatusPolicyViolation, "connection too slow to keep up with messages")
-			},
-			booted:     make(map[string]struct{}),
-			muted:      make(map[string]struct{}),
-			blocked:    make(map[string]struct{}),
-			messageIDs: make(map[int64]struct{}),
-			ChatStatus: "online",
-		}
 
 		s.AddSubscriber(sub)
 		defer s.DeleteSubscriber(sub)
@@ -280,6 +332,10 @@ func (s *Server) GetSubscriber(username string) (*Subscriber, error) {
 
 // DeleteSubscriber removes a subscriber from the server.
 func (s *Server) DeleteSubscriber(sub *Subscriber) {
+	if sub == nil {
+		return
+	}
+
 	log.Error("DeleteSubscriber: %s", sub.Username)
 
 	// Cancel its context to clean up the for-loop goroutine.

src/App.vue

@@ -143,6 +143,7 @@ export default {
 
             // Misc. user preferences (TODO: move all of them here)
             prefs: {
+                usePolling: false,   // use the polling API instead of WebSockets.
                 joinMessages: true,  // show "has entered the room" in public channels
                 exitMessages: false, // hide exit messages by default in public channels
                 watchNotif: true,    // notify in chat about cameras being watched
@@ -461,6 +462,12 @@ export default {
         "prefs.muteSounds": function () {
             LocalStorage.set('muteSounds', this.prefs.muteSounds);
         },
+        "prefs.usePolling": function () {
+            LocalStorage.set('usePolling', this.prefs.usePolling);
+
+            // Reset the chat client on change.
+            this.resetChatClient();
+        },
         "prefs.closeDMs": function () {
             LocalStorage.set('closeDMs', this.prefs.closeDMs);
 
@@ -469,6 +476,12 @@ export default {
         },
     },
     computed: {
+        connected() {
+            if (this.client.connected != undefined) {
+                return this.client.connected();
+            }
+            return false;
+        },
         chatHistory() {
             if (this.channels[this.channel] == undefined) {
                 return [];
@@ -772,6 +785,9 @@ export default {
             }
 
             // Misc preferences
+            if (settings.usePolling != undefined) {
+                this.prefs.usePolling = settings.usePolling === true;
+            }
             if (settings.joinMessages != undefined) {
                 this.prefs.joinMessages = settings.joinMessages === true;
             }
@@ -827,7 +843,7 @@ export default {
                 return;
             }
 
-            if (!this.client.connected()) {
+            if (!this.connected) {
                 this.ChatClient("You are not connected to the server.");
                 return;
             }
@@ -979,7 +995,7 @@ export default {
         // Sync the current user state (such as video broadcasting status) to
         // the backend, which will reload everybody's Who List.
         sendMe() {
-            if (!this.client.connected()) return;
+            if (!this.connected) return;
             this.client.send({
                 action: "me",
                 video: this.myVideoFlag,
@@ -1288,12 +1304,12 @@ export default {
 
         // Dial the WebSocket connection.
         dial() {
-            this.ChatClient("Establishing connection to server...");
-
             // Set up the ChatClient connection.
             this.client = new ChatClient({
+                usePolling: this.prefs.usePolling,
                 onClientError: this.ChatClient,
 
+                username: this.username,
                 jwt: this.jwt,
                 prefs: this.prefs,
 
@@ -1317,12 +1333,28 @@ export default {
                 },
                 pushHistory: this.pushHistory,
                 onNewJWT: jwt => {
-                    this.jwt.token = msg.jwt;
+                    this.ChatClient("new jwt: " + jwt);
+                    this.jwt.token = jwt;
                 },
             });
 
             this.client.dial();
         },
+        resetChatClient() {
+            if (!this.connected) return;
+
+            // Reset the ChatClient, e.g. when toggling between WebSocket vs. Polling methods.
+            this.ChatClient(
+                "Your connection method to the chat server has been updated; attempting to reconnect now.",
+            );
+
+            window.requestAnimationFrame(() => {
+                this.client.disconnect();
+                setTimeout(() => {
+                    this.dial();
+                }, 1000);
+            });
+        },
 
         /**
          * WebRTC concerns.
@@ -3367,6 +3399,31 @@ export default {
                             </p>
                         </div>
 
+                        <div class="field">
+                            <label class="label mb-0">
+                                Server Connection Method
+                            </label>
+                            <label class="checkbox">
+                                <input type="radio" v-model="prefs.usePolling" :value="false">
+                                WebSockets (realtime connection; recommended for most people)
+                            </label>
+                            <label class="checkbox">
+                                <input type="radio" v-model="prefs.usePolling" :value="true">
+                                Polling (check for new messages every 5 seconds)
+                            </label>
+                            <p class="help">
+                                By default the chat server requires a constant WebSockets connection to stay online.
+                                If you are experiencing frequent disconnects (e.g. because you are on a slow or
+                                unstable network connection), try switching to the "Polling" method which will be
+                                more robust, at the cost of up to 5-seconds latency to receive new messages.
+
+                                <!-- If disconnected currently, tell them to refresh. -->
+                                <span v-if="!connected" class="has-text-danger">
+                                    Notice: you may need to refresh the chat page after changing this setting.
+                                </span>
+                            </p>
+                        </div>
+
                     </div>
 
                 </div>

src/lib/ChatClient.js

@@ -11,6 +11,7 @@ class ChatClient {
         usePolling=false,
         onClientError,
 
+        username,
         jwt,   // JWT token for authorization
         prefs, // User preferences for 'me' action (close DMs, etc)
 
@@ -40,6 +41,7 @@ class ChatClient {
         // Pointer to the 'ChatClient(message)' command from the main app.
         this.ChatClient = onClientError;
 
+        this.username = username;
         this.jwt = jwt;
         this.prefs = prefs;
 
@@ -67,13 +69,25 @@ class ChatClient {
         this.ws = {
             conn: null,
             connected: false,
+
+            // Disconnect spamming: don't retry too many times.
+            reconnect: true, // unless told to go away
+            disconnectLimit: 2,
+            disconnectCount: 0,
         };
+
+        // Polling connection.
+        this.polling = {
+            username: "",
+            sessionID: "",
+            timeout: null, // setTimeout for next poll.
+        }
     }
 
     // Connected polls if the client is connected.
     connected() {
         if (this.usePolling) {
-            return true;
+            return this.polling.timeout != null && this.polling.sessionID != "";
         }
         return this.ws.connected;
     }
@@ -81,16 +95,47 @@ class ChatClient {
     // Disconnect from the server.
     disconnect() {
         if (this.usePolling) {
-            throw new Exception("Not implemented");
+            this.polling.sessionID = "";
+            this.polling.username = "";
+            this.stopPolling();
+            this.ChatClient("You have disconnected from the server.");
+            return;
         }
-        this.ws.conn.close();
+
+        this.ws.connected = false;
+        this.ws.conn.close(1000, "server asked to close the connection");
     }
 
     // Common function to send a message to the server. The message
     // is a JSON object before stringify.
     send(message) {
         if (this.usePolling) {
-            throw new Exception("Not implemented");
+            fetch("/poll", {
+                method: "POST",
+                mode: "same-origin",
+                cache: "no-cache",
+                credentials: "same-origin",
+                headers: {
+                    "Content-Type": "application/json",
+                },
+                body: JSON.stringify({
+                    username: this.polling.username,
+                    session_id: this.polling.sessionID,
+                    msg: message,
+                })
+            }).then(resp => resp.json()).then(resp => {
+                console.log(resp);
+
+                // Store sessionID information.
+                this.polling.sessionID = resp.session_id;
+                this.polling.username  = resp.username;
+                for (let msg of resp.messages) {
+                    this.handle(msg);
+                }
+            }).catch(err => {
+                this.ChatClient("Error from polling API: " + err);
+            });
+            return;
         }
 
         if (!this.ws.connected) {
@@ -98,7 +143,6 @@ class ChatClient {
             return;
         }
 
-        console.log("send:", message);
         if (typeof(message) !== "string") {
             message = JSON.stringify(message);
         }
@@ -157,9 +201,8 @@ class ChatClient {
                 break;
             case "disconnect":
                 this.onWho({ whoList: [] });
-                this.disconnect = true;
+                this.ws.reconnect = false;
-                this.ws.connected = false;
+                this.disconnect();
-                this.ws.conn.close(1000, "server asked to close the connection");
                 break;
             case "ping":
                 // New JWT token?
@@ -170,7 +213,7 @@ class ChatClient {
                 // Reset disconnect retry counter: if we were on long enough to get
                 // a ping, we're well connected and can reconnect no matter how many
                 // times the chat server is rebooted.
-                this.disconnectCount = 0;
+                this.ws.disconnectCount = 0;
                 break;
             default:
                 console.error("Unexpected action: %s", JSON.stringify(msg));
@@ -179,6 +222,21 @@ class ChatClient {
 
     // Dial the WebSocket.
     dial() {
+        // Polling API?
+        if (this.usePolling) {
+            this.ChatClient("Connecting to the server via polling API...");
+            this.startPolling();
+
+            // Log in now.
+            this.send({
+                action: "login",
+                username: this.username,
+                jwt: this.jwt.token,
+                dnd: this.prefs.closeDMs,
+            });
+            return;
+        }
+
         this.ChatClient("Establishing connection to server...");
 
         const proto = location.protocol === 'https:' ? 'wss' : 'ws';
@@ -191,16 +249,22 @@ class ChatClient {
             this.ws.connected = false;
             this.ChatClient(`WebSocket Disconnected code: ${ev.code}, reason: ${ev.reason}`);
 
-            this.disconnectCount++;
+            this.ws.disconnectCount++;
-            if (this.disconnectCount > this.disconnectLimit) {
+            if (this.ws.disconnectCount > this.ws.disconnectLimit) {
-                this.ChatClient(`It seems there's a problem connecting to the server. Please try some other time.`);
+                this.ChatClient(
+                    `It seems there's a problem connecting to the server. Please try some other time.<br><br>` +
+                    `If you experience this problem frequently, try going into the Chat Settings 'Misc' tab ` +
+                    `and switch to the 'Polling' Server Connection method.`
+                );
                 return;
             }
 
-            if (!this.disconnect) {
+            if (this.ws.reconnect) {
                 if (ev.code !== 1001 && ev.code !== 1000) {
                     this.ChatClient("Reconnecting in 5s");
-                    setTimeout(this.dial, 5000);
+                    setTimeout(() => {
+                        this.dial();
+                    }, 5000);
                 }
             }
         });
@@ -240,6 +304,36 @@ class ChatClient {
 
         this.ws.conn = conn;
     }
+
+    // Start the polling interval.
+    startPolling() {
+        if (!this.usePolling) return;
+        this.stopPolling();
+
+        this.polling.timeout = setTimeout(() => {
+            this.poll();
+            this.startPolling();
+        }, 5000);
+    }
+
+    // Poll the API.
+    poll() {
+        if (!this.usePolling) {
+            this.stopPolling();
+            return;
+        }
+        this.send({
+            action: "ping",
+        });
+        this.startPolling();
+    }
+
+    // Stop polling.
+    stopPolling() {
+        if (this.polling.timeout != null) {
+            clearTimeout(this.polling.timeout);
+        }
+    }
 }
 
 export default ChatClient;

src/lib/LocalStorage.js

@@ -18,6 +18,7 @@ const keys = {
     'rememberExpresslyClosed': Boolean,
 
     // Booleans
+    'usePolling': Boolean,  // use the polling API instead of WebSocket
     'joinMessages': Boolean,
     'exitMessages': Boolean,
     'watchNotif': Boolean,