Ditch long polling

Signal/src/AppDelegate.h

@@ -8,8 +8,8 @@ extern NSString *const AppDelegateStoryboardMain;
 
 @interface AppDelegate : UIResponder <UIApplicationDelegate>
 
-- (void)startLongPollerIfNeeded;
+- (void)startPollerIfNeeded;
-- (void)stopLongPollerIfNeeded;
+- (void)stopPollerIfNeeded;
 - (void)setUpDefaultPublicChatsIfNeeded;
 - (void)startOpenGroupPollersIfNeeded;
 - (void)stopOpenGroupPollersIfNeeded;

Signal/src/AppDelegate.m

@@ -69,7 +69,7 @@ static BOOL isInternalTestVersion = NO;
 
 // Loki
 @property (nonatomic) LKP2PServer *lokiP2PServer;
-@property (nonatomic) LKLongPoller *lokiLongPoller;
+@property (nonatomic) LKPoller *lokiPoller;
 @property (nonatomic) LKRSSFeedPoller *lokiNewsFeedPoller;
 @property (nonatomic) LKRSSFeedPoller *lokiMessengerUpdatesFeedPoller;
 
@@ -181,7 +181,7 @@ static BOOL isInternalTestVersion = NO;
     [DDLog flushLog];
 
     // Loki: Stop pollers
-    [self stopLongPollerIfNeeded];
+    [self stopPollerIfNeeded];
     [self stopOpenGroupPollersIfNeeded];
 }
 
@@ -202,7 +202,7 @@ static BOOL isInternalTestVersion = NO;
     [DDLog flushLog];
 
     // Loki: Stop pollers
-    [self stopLongPollerIfNeeded];
+    [self stopPollerIfNeeded];
     [self stopOpenGroupPollersIfNeeded];
 
     if (self.lokiP2PServer) { [self.lokiP2PServer stop]; }
@@ -784,7 +784,7 @@ static BOOL isInternalTestVersion = NO;
             [LKP2PAPI broadcastOnlineStatus];
 
             // Loki: Start pollers
-            [self startLongPollerIfNeeded];
+            [self startPollerIfNeeded];
             [self startOpenGroupPollersIfNeeded];
 
             // Loki: Get device links
@@ -1477,7 +1477,7 @@ static BOOL isInternalTestVersion = NO;
         [self.lokiFriendRequestExpirationJob startIfNecessary];
         
         // Loki: Start pollers
-        [self startLongPollerIfNeeded];
+        [self startPollerIfNeeded];
         [self startOpenGroupPollersIfNeeded];
 
         // Loki: Get device links
@@ -1591,12 +1591,12 @@ static BOOL isInternalTestVersion = NO;
 
 #pragma mark - Loki
 
-- (void)setUpLongPollerIfNeeded
+- (void)setUpPollerIfNeeded
 {
-    if (self.lokiLongPoller != nil) { return; }
+    if (self.lokiPoller != nil) { return; }
     NSString *userHexEncodedPublicKey = OWSIdentityManager.sharedManager.identityKeyPair.hexEncodedPublicKey;
     if (userHexEncodedPublicKey == nil) { return; }
-    self.lokiLongPoller = [[LKLongPoller alloc] initOnMessagesReceived:^(NSArray<SSKProtoEnvelope *> *messages) {
+    self.lokiPoller = [[LKPoller alloc] initOnMessagesReceived:^(NSArray<SSKProtoEnvelope *> *messages) {
         for (SSKProtoEnvelope *message in messages) {
             NSData *data = [message serializedDataAndReturnError:nil];
             if (data != nil) {
@@ -1608,15 +1608,15 @@ static BOOL isInternalTestVersion = NO;
     }];
 }
 
-- (void)startLongPollerIfNeeded
+- (void)startPollerIfNeeded
 {
-    [self setUpLongPollerIfNeeded];
+    [self setUpPollerIfNeeded];
-    [self.lokiLongPoller startIfNeeded];
+    [self.lokiPoller startIfNeeded];
 }
 
-- (void)stopLongPollerIfNeeded
+- (void)stopPollerIfNeeded
 {
-    [self.lokiLongPoller stopIfNeeded];
+    [self.lokiPoller stopIfNeeded];
 }
 
 - (void)setUpDefaultPublicChatsIfNeeded
@@ -1713,7 +1713,7 @@ static BOOL isInternalTestVersion = NO;
     [SSKEnvironment.shared.messageSenderJobQueue clearAllJobs];
     [SSKEnvironment.shared.identityManager clearIdentityKey];
     [LKAPI clearRandomSnodePool];
-    [self stopLongPollerIfNeeded];
+    [self stopPollerIfNeeded];
     [self stopOpenGroupPollersIfNeeded];
     [self.lokiNewsFeedPoller stop];
     [self.lokiMessengerUpdatesFeedPoller stop];

Signal/src/Loki/View Controllers/LandingVC.swift

@@ -155,7 +155,7 @@ final class LandingVC : BaseVC, LinkDeviceVCDelegate, DeviceLinkingModalDelegate
         TSAccountManager.sharedInstance().phoneNumberAwaitingVerification = keyPair.hexEncodedPublicKey
         TSAccountManager.sharedInstance().didRegister()
         let appDelegate = UIApplication.shared.delegate as! AppDelegate
-        appDelegate.startLongPollerIfNeeded()
+        appDelegate.startPollerIfNeeded()
         let deviceLinkingModal = DeviceLinkingModal(mode: .slave, delegate: self)
         deviceLinkingModal.modalPresentationStyle = .overFullScreen
         deviceLinkingModal.modalTransitionStyle = .crossDissolve
@@ -176,7 +176,7 @@ final class LandingVC : BaseVC, LinkDeviceVCDelegate, DeviceLinkingModalDelegate
     
     func handleDeviceLinkingModalDismissed() {
         let appDelegate = UIApplication.shared.delegate as! AppDelegate
-        appDelegate.stopLongPollerIfNeeded()
+        appDelegate.stopPollerIfNeeded()
         TSAccountManager.sharedInstance().resetForReregistration()
     }
     

Signal/src/ViewControllers/HomeView/HomeViewController.m

@@ -681,7 +681,7 @@ typedef NS_ENUM(NSInteger, HomeViewControllerSection) {
             [SSKEnvironment.shared.identityManager clearIdentityKey];
             [LKAPI clearRandomSnodePool];
             AppDelegate *appDelegate = (AppDelegate *)UIApplication.sharedApplication.delegate;
-            [appDelegate stopLongPollerIfNeeded];
+            [appDelegate stopPollerIfNeeded];
             [appDelegate stopOpenGroupPollersIfNeeded];
             [SSKEnvironment.shared.tsAccountManager resetForReregistration];
             UIViewController *rootViewController = [[OnboardingController new] initialViewController];

SignalServiceKit/src/Loki/API/LokiPoller.swift

@@ -1,20 +1,16 @@
 import PromiseKit
 
-@objc(LKLongPoller)
+@objc(LKPoller)
-public final class LokiLongPoller : NSObject {
+public final class LokiPoller : NSObject {
     private let onMessagesReceived: ([SSKProtoEnvelope]) -> Void
     private let storage = OWSPrimaryStorage.shared()
     private var hasStarted = false
     private var hasStopped = false
-    private var connections = Set<Promise<Void>>()
     private var usedSnodes = Set<LokiAPITarget>()
 
     // MARK: Settings
-    private let connectionCount = 3
+    private static let pollInterval: TimeInterval = 1
-    private let retryInterval: TimeInterval = 4
+    private static let retryInterval: TimeInterval = 4
-
-    // MARK: Convenience
-    private var userHexEncodedPublicKey: String { return getUserHexEncodedPublicKey() }
 
     // MARK: Initialization
     @objc public init(onMessagesReceived: @escaping ([SSKProtoEnvelope]) -> Void) {
@@ -25,7 +21,7 @@ public final class LokiLongPoller : NSObject {
     // MARK: Public API
     @objc public func startIfNeeded() {
         guard !hasStarted else { return }
-        print("[Loki] Started long polling.")
+        print("[Loki] Started polling.")
         hasStarted = true
         hasStopped = false
         openConnections()
@@ -33,7 +29,7 @@ public final class LokiLongPoller : NSObject {
 
     @objc public func stopIfNeeded() {
         guard !hasStopped else { return }
-        print("[Loki] Stopped long polling.")
+        print("[Loki] Stopped polling.")
         hasStarted = false
         hasStopped = true
         usedSnodes.removeAll()
@@ -42,49 +38,46 @@ public final class LokiLongPoller : NSObject {
     // MARK: Private API
     private func openConnections() {
         guard !hasStopped else { return }
-        LokiAPI.getSwarm(for: userHexEncodedPublicKey).then { [weak self] _ -> Guarantee<[Result<Void>]> in
+        LokiAPI.getSwarm(for: getUserHexEncodedPublicKey()).then { [weak self] _ -> Promise<Void> in
-            guard let strongSelf = self else { return Guarantee.value([Result<Void>]()) }
+            guard let strongSelf = self else { return Promise { $0.fulfill(()) } }
             strongSelf.usedSnodes.removeAll()
-            let connections: [Promise<Void>] = (0..<strongSelf.connectionCount).map { _ in
+            let (promise, seal) = Promise<Void>.pending()
-                let (promise, seal) = Promise<Void>.pending()
+            strongSelf.pollNextSnode(seal: seal)
-                strongSelf.openConnectionToNextSnode(seal: seal)
+            return promise
-                return promise
-            }
-            strongSelf.connections = Set(connections)
-            return when(resolved: connections)
         }.ensure { [weak self] in
             guard let strongSelf = self else { return }
-            Timer.scheduledTimer(withTimeInterval: strongSelf.retryInterval, repeats: false) { _ in
+            Timer.scheduledTimer(withTimeInterval: LokiPoller.retryInterval, repeats: false) { _ in
                 guard let strongSelf = self else { return }
                 strongSelf.openConnections()
             }
         }
     }
 
-    private func openConnectionToNextSnode(seal: Resolver<Void>) {
+    private func pollNextSnode(seal: Resolver<Void>) {
+        let userHexEncodedPublicKey = getUserHexEncodedPublicKey()
         let swarm = LokiAPI.swarmCache[userHexEncodedPublicKey] ?? []
-        let userHexEncodedPublicKey = self.userHexEncodedPublicKey
         let unusedSnodes = Set(swarm).subtracting(usedSnodes)
         if !unusedSnodes.isEmpty {
+            // randomElement() uses the system's default random generator, which is cryptographically secure
             let nextSnode = unusedSnodes.randomElement()!
             usedSnodes.insert(nextSnode)
-            print("[Loki] Opening long polling connection to \(nextSnode).")
+            print("[Loki] Polling \(nextSnode).")
-            longPoll(nextSnode, seal: seal).catch(on: LokiAPI.errorHandlingQueue) { [weak self] error in
+            poll(nextSnode, seal: seal).catch(on: LokiAPI.errorHandlingQueue) { [weak self] error in
-                print("[Loki] Long polling connection to \(nextSnode) failed; dropping it and switching to next snode.")
+                print("[Loki] Polling \(nextSnode) failed; dropping it and switching to next snode.")
                 LokiAPI.dropIfNeeded(nextSnode, hexEncodedPublicKey: userHexEncodedPublicKey)
-                self?.openConnectionToNextSnode(seal: seal)
+                self?.pollNextSnode(seal: seal)
             }
         } else {
             seal.fulfill(())
         }
     }
 
-    private func longPoll(_ target: LokiAPITarget, seal: Resolver<Void>) -> Promise<Void> {
+    private func poll(_ target: LokiAPITarget, seal: Resolver<Void>) -> Promise<Void> {
-        return LokiAPI.getRawMessages(from: target, usingLongPolling: true).then(on: DispatchQueue.global()) { [weak self] rawResponse -> Promise<Void> in
+        return LokiAPI.getRawMessages(from: target, usingLongPolling: false).then(on: DispatchQueue.global()) { [weak self] rawResponse -> Promise<Void> in
             guard let strongSelf = self, !strongSelf.hasStopped else { return Promise.value(()) }
             let messages = LokiAPI.parseRawMessagesResponse(rawResponse, from: target)
             strongSelf.onMessagesReceived(messages)
-            return strongSelf.longPoll(target, seal: seal)
+            return strongSelf.poll(target, seal: seal)
         }
     }
 }