WIP2

doc/impl-thoughts/RECONNECTING.md

@@ -1,22 +1,22 @@
 # Reconnecting
 
-`HomeServerApi` notifies `Reconnecter` of network call failure
+`HomeServerApi` notifies `Reconnector` of network call failure
 
-`Reconnecter` listens for online/offline event
+`Reconnector` listens for online/offline event
 
-`Reconnecter` polls `/versions` with a `RetryDelay` (implemented as ExponentialRetryDelay, also used by SendScheduler if no retry_after_ms is given)
+`Reconnector` polls `/versions` with a `RetryDelay` (implemented as ExponentialRetryDelay, also used by SendScheduler if no retry_after_ms is given)
 
-`Reconnecter` emits an event when sync and message sending should retry
+`Reconnector` emits an event when sync and message sending should retry
 
-`Sync` listen to `Reconnecter`
+`Sync` listen to `Reconnector`
 `Sync` notifies when the catchup sync has happened
 
-`Reconnecter` has state:
+`Reconnector` has state:
     - disconnected (and retrying at x seconds from timestamp)
     - reconnecting (call /versions, and if successful /sync)
     - connected
 
-`Reconnecter` has a method to try to connect now
+`Reconnector` has a method to try to connect now
 
 `SessionStatus` can be:
     - disconnected (and retrying at x seconds from timestamp)
@@ -31,4 +31,4 @@ rooms should report how many messages they have queued up, and each time they se
 `SendReporter` (passed from `Session` to `Room`, passed down to `SendQueue`), with:
  - setPendingEventCount(roomId, count)
 
-`Session` listens to `Reconnecter` to update it's status, but perhaps we wait to send messages until catchup sync is done
+`Session` listens to `Reconnector` to update it's status, but perhaps we wait to send messages until catchup sync is done

src/domain/BrawlViewModel.js

@@ -126,7 +126,11 @@ export default class BrawlViewModel extends EventEmitter {
         try {
             this._loading = true;
             this._loadingText = "Loading your conversations…";
-            const hsApi = this._createHsApi(sessionInfo.homeServer, sessionInfo.accessToken);
+            const reconnector = new Reconnector(
+                new ExponentialRetryDelay(2000, this._clock.createTimeout),
+                this._clock.createMeasure
+            );
+            const hsApi = this._createHsApi(sessionInfo.homeServer, sessionInfo.accessToken, reconnector);
             const storage = await this._storageFactory.create(sessionInfo.id);
             // no need to pass access token to session
             const filteredSessionInfo = {
@@ -136,11 +140,17 @@ export default class BrawlViewModel extends EventEmitter {
             };
             const session = new Session({storage, sessionInfo: filteredSessionInfo, hsApi});
             // show spinner now, with title loading stored data?
-
             this.emit("change", "activeSection");
             await session.load();
             const sync = new Sync({hsApi, storage, session});
 
+            reconnector.on("state", state => {
+                if (state === ConnectionState.Online) {
+                    sync.start();
+                    session.notifyNetworkAvailable(reconnector.lastVersionsResponse);
+                }
+            });
+            
             const needsInitialSync = !session.syncToken;
             if (!needsInitialSync) {
                 this._showSession(session, sync);

src/main.js

@@ -5,6 +5,7 @@ import StorageFactory from "./matrix/storage/idb/create.js";
 import SessionsStore from "./matrix/sessions-store/localstorage/SessionsStore.js";
 import BrawlViewModel from "./domain/BrawlViewModel.js";
 import BrawlView from "./ui/web/BrawlView.js";
+import DOMClock from "./utils/DOMClock.js";
 
 export default async function main(container) {
     try {
@@ -17,14 +18,13 @@ export default async function main(container) {
         // const recorder = new RecordRequester(fetchRequest);
         // const request = recorder.request;
         // window.getBrawlFetchLog = () => recorder.log();
-
         // normal network:
         const request = fetchRequest;
         const vm = new BrawlViewModel({
             storageFactory: new StorageFactory(),
-            createHsApi: (homeServer, accessToken = null) => new HomeServerApi({homeServer, accessToken, request}),
+            createHsApi: (homeServer, accessToken, reconnector) => new HomeServerApi({homeServer, accessToken, request, reconnector}),
             sessionStore: new SessionsStore("brawl_sessions_v1"),
-            clock: Date //just for `now` fn
+            clock: new DOMClock(),
         });
         await vm.load();
         const view = new BrawlView(vm);

src/matrix/Reconnector.js

@@ -1,53 +1,49 @@
-class Clock {
-    // use cases
-    // StopWatch: not sure I like that name ... but measure time difference from start to current time
-    // Timeout: wait for a given number of ms, and be able to interrupt the wait
-    //  Clock.timeout() -> creates a new timeout?
-    // Now: get current timestamp
-    //  Clock.now(), or pass Clock.now so others can do now()
-    // 
-    // should use subinterfaces so we can only pass part needed to other constructors
-    // 
-}
-
-
 // need to prevent memory leaks here!
 export class DomOnlineDetected {
-    constructor(reconnecter) {
+    constructor(reconnector) {
         // window.addEventListener('offline', () => appendOnlineStatus(false));
         // window.addEventListener('online', () => appendOnlineStatus(true));
         // appendOnlineStatus(navigator.onLine);
-        // on online, reconnecter.tryNow()
+        // on online, reconnector.tryNow()
     }
 }
 
 export class ExponentialRetryDelay {
-    constructor(start = 2000, delay) {
+    constructor(start = 2000, createTimeout) {
         this._start = start;
         this._current = start;
-        this._delay = delay;
+        this._createTimeout = createTimeout;
         this._max = 60 * 5 * 1000; //5 min
-        this._timer = null;
+        this._timeout = null;
     }
 
     async waitForRetry() {
-        this._timer = this._delay(this._current);
+        this._timeout = this._createTimeout(this._current);
         try {
-            await this._timer.timeout();
+            await this._timeout.elapsed();
             // only increase delay if we didn't get interrupted
             const seconds = this._current / 1000;
             const powerOfTwo = (seconds * seconds) * 1000;
             this._current = Math.max(this._max, powerOfTwo);
+        } catch(err) {
+            // swallow AbortError, means skipWaiting was called
+            if (!(err instanceof AbortError)) {
+                throw err;
+            }
         } finally {
-            this._timer = null;
+            this._timeout = null;
+        }
+    }
+
+    skipWaiting() {
+        if (this._timeout) {
+            this._timeout.abort();
         }
     }
 
     reset() {
         this._current = this._start;
-        if (this._timer) {
+        this.skipWaiting();
-            this._timer.abort();
-        }
     }
 
     get nextValue() {
@@ -80,13 +76,12 @@ export const ConnectionState = createEnum(
     "Online"
 );
 
-export class Reconnecter {
+export class Reconnector {
-    constructor({hsApi, retryDelay, clock}) {
+    constructor({retryDelay, createTimeMeasure}) {
         this._online 
         this._retryDelay = retryDelay;
         this._currentDelay = null;
-        this._hsApi = hsApi;
+        this._createTimeMeasure = createTimeMeasure;
-        this._clock = clock;
         // assume online, and do our thing when something fails
         this._state = ConnectionState.Online;
         this._isReconnecting = false;
@@ -102,25 +97,22 @@ export class Reconnecter {
     }
 
     get retryIn() {
-        return  this._stateSince.measure();
+        if (this._state === ConnectionState.Waiting) {
+            return this._retryDelay.nextValue - this._stateSince.measure();
+        }
+        return 0;
     }
 
-    onRequestFailed() {
+    onRequestFailed(hsApi) {
         if (!this._isReconnecting) {
             this._setState(ConnectionState.Offline);
-            // do something with versions response of loop here?
+            this._reconnectLoop(hsApi);
-            // we might want to pass it to session to know what server supports?
-            // so emit it ...
-            this._reconnectLoop();
-            // start loop
         }
     }
 
-    // don't throw from here
     tryNow() {
-        // skip waiting
+        if (this._retryDelay) {
-        if (this._currentDelay) {
+            this._retryDelay.skipWaiting();
-            this._currentDelay.abort();
         }
     }
 
@@ -128,7 +120,7 @@ export class Reconnecter {
         if (state !== this._state) {
             this._state = state;
             if (this._state === ConnectionState.Waiting) {
-                this._stateSince = this._clock.stopwatch();
+                this._stateSince = this._createTimeMeasure();
             } else {
                 this._stateSince = null;
             }
@@ -136,30 +128,23 @@ export class Reconnecter {
         }
     }
     
-    async _reconnectLoop() {
+    async _reconnectLoop(hsApi) {
         this._isReconnecting = true;
-        this._retryDelay.reset();
         this._versionsResponse = null;
+        this._retryDelay.reset();
 
         while (!this._versionsResponse) {
-            // TODO: should we wait first or request first?
-            // as we've just failed a request? I guess no harm in trying immediately
             try {
                 this._setState(ConnectionState.Reconnecting);
-                const versionsRequest = this._hsApi.versions(10000);
+                // use 10s timeout, because we don't want to be waiting for
+                // a stale connection when we just came online again
+                const versionsRequest = hsApi.versions({timeout: 10000});
                 this._versionsResponse = await versionsRequest.response();
                 this._setState(ConnectionState.Online);
             } catch (err) {
+                // NetworkError or AbortError from timeout
                 this._setState(ConnectionState.Waiting);
-                this._currentDelay = this._retryDelay.next();
+                await this._retryDelay.waitForRetry();
-                try {
-                    await this._currentDelay
-                } catch (err) {
-                    // waiting interrupted, we should retry immediately,
-                    // swallow error
-                } finally {
-                    this._currentDelay = null;
-                }
             }
         }
     }

src/matrix/hs-api.js

@@ -1,5 +1,6 @@
 import {
     HomeServerError,
+    NetworkError,
 } from "./error.js";
 
 class RequestWrapper {
@@ -28,19 +29,21 @@ class RequestWrapper {
 }
 
 export default class HomeServerApi {
-    constructor({homeServer, accessToken, request}) {
+    constructor({homeServer, accessToken, request, createTimeout, reconnector}) {
         // store these both in a closure somehow so it's harder to get at in case of XSS?
         // one could change the homeserver as well so the token gets sent there, so both must be protected from read/write
         this._homeserver = homeServer;
         this._accessToken = accessToken;
         this._requestFn = request;
+        this._createTimeout = createTimeout;
+        this._reconnector = reconnector;
     }
 
     _url(csPath) {
         return `${this._homeserver}/_matrix/client/r0${csPath}`;
     }
 
-    _request(method, url, queryParams = {}, body) {
+    _request(method, url, queryParams = {}, body, options) {
         const queryString = Object.entries(queryParams)
             .filter(([, value]) => value !== undefined)
             .map(([name, value]) => {
@@ -66,51 +69,73 @@ export default class HomeServerApi {
             headers,
             body: bodyString,
         });
-        return new RequestWrapper(method, url, requestResult);
+
+        if (options.timeout) {
+            const timeout = this._createTimeout(options.timeout);
+            // abort request if timeout finishes first
+            timeout.elapsed().then(
+                () => requestResult.abort(),
+                () => {}    // ignore AbortError
+            );
+            // abort timeout if request finishes first
+            requestResult.response().then(() => timeout.abort());
+        }
+
+
+        const wrapper = new RequestWrapper(method, url, requestResult);
+        
+        if (this._reconnector) {
+            wrapper.response().catch(err => {
+                if (err instanceof NetworkError) {
+                    this._reconnector.onRequestFailed(this);
+                }
+            });
+        }
+
+        return wrapper;
     }
 
-    _post(csPath, queryParams, body) {
+    _post(csPath, queryParams, body, options) {
-        return this._request("POST", this._url(csPath), queryParams, body);
+        return this._request("POST", this._url(csPath), queryParams, body, options);
     }
 
-    _put(csPath, queryParams, body) {
+    _put(csPath, queryParams, body, options) {
-        return this._request("PUT", this._url(csPath), queryParams, body);
+        return this._request("PUT", this._url(csPath), queryParams, body, options);
     }
 
-    _get(csPath, queryParams, body) {
+    _get(csPath, queryParams, body, options) {
-        return this._request("GET", this._url(csPath), queryParams, body);
+        return this._request("GET", this._url(csPath), queryParams, body, options);
     }
 
-    sync(since, filter, timeout) {
+    sync(since, filter, timeout, options = null) {
-        return this._get("/sync", {since, timeout, filter});
+        return this._get("/sync", {since, timeout, filter}, null, options);
     }
 
     // params is from, dir and optionally to, limit, filter.
-    messages(roomId, params) {
+    messages(roomId, params, options = null) {
-        return this._get(`/rooms/${encodeURIComponent(roomId)}/messages`, params);
+        return this._get(`/rooms/${encodeURIComponent(roomId)}/messages`, params, null, options);
     }
 
-    send(roomId, eventType, txnId, content) {
+    send(roomId, eventType, txnId, content, options = null) {
-        return this._put(`/rooms/${encodeURIComponent(roomId)}/send/${encodeURIComponent(eventType)}/${encodeURIComponent(txnId)}`, {}, content);
+        return this._put(`/rooms/${encodeURIComponent(roomId)}/send/${encodeURIComponent(eventType)}/${encodeURIComponent(txnId)}`, {}, content, options);
     }
 
-    passwordLogin(username, password) {
+    passwordLogin(username, password, options = null) {
-        return this._post("/login", undefined, {
+        return this._post("/login", null, {
           "type": "m.login.password",
           "identifier": {
             "type": "m.id.user",
             "user": username
           },
           "password": password
-        });
+        }, options);
     }
 
-    createFilter(userId, filter) {
+    createFilter(userId, filter, options = null) {
-        return this._post(`/user/${encodeURIComponent(userId)}/filter`, undefined, filter);
+        return this._post(`/user/${encodeURIComponent(userId)}/filter`, null, filter, options);
     }
 
-    versions(timeout) {
+    versions(options = null) {
-        // TODO: implement timeout
+        return this._request("GET", `${this._homeserver}/_matrix/client/versions`, null, options);
-        return this._request("GET", `${this._homeserver}/_matrix/client/versions`);
     }
 }

src/matrix/session.js

@@ -40,7 +40,7 @@ export default class Session {
         }));
     }
 
-    notifyNetworkAvailable() {
+    notifyNetworkAvailable(lastVersionResponse) {
         for (const [, room] of this._rooms) {
             room.resumeSending();
         }

src/matrix/sync.js

@@ -33,6 +33,7 @@ export default class Sync extends EventEmitter {
         return this._isSyncing;
     }
 
+    // this should not throw?
     // returns when initial sync is done
     async start() {
         if (this._isSyncing) {

src/utils/DOMClock.js

@@ -3,22 +3,25 @@ import {AbortError} from "./error.js";
 class DOMTimeout {
     constructor(ms) {
         this._reject = null;
+        this._handle = null;
         this._promise = new Promise((resolve, reject) => {
             this._reject = reject;
-            setTimeout(() => {
+            this._handle = setTimeout(() => {
                 this._reject = null;
                 resolve();
             }, ms);
         });
     }
 
-    get elapsed() {
+    elapsed() {
         return this._promise;
     }
 
     abort() {
         if (this._reject) {
             this._reject(new AbortError());
+            clearTimeout(this._handle);
+            this._handle = null;
             this._reject = null;
         }
     }