From ae8d2029f68ede5ecf40b555af12d034c7bd00bb Mon Sep 17 00:00:00 2001
From: Lucas Leblow <lucas@quiet.chat>
Date: Fri, 12 Apr 2024 10:40:31 -0700
Subject: [PATCH] fix: Re-dial peers when resuming from background on iOS

---
 packages/backend/src/backendManager.ts        | 16 +++++++++
 .../connections-manager.service.ts            |  5 +++
 .../backend/src/nest/libp2p/libp2p.service.ts | 34 +++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/packages/backend/src/backendManager.ts b/packages/backend/src/backendManager.ts
index 42fa25d78b..c0466b6d2e 100644
--- a/packages/backend/src/backendManager.ts
+++ b/packages/backend/src/backendManager.ts
@@ -114,7 +114,21 @@ export const runBackendMobile = async () => {
     connectionsManager.closeSocket()
   })
 
+  // I've noticed that two of these 'open' events can occur in quick
+  // succession and of course the event handlers are not awaited. This
+  // is a simple fix, but perhaps we can also look into the cause in
+  // more depth.
+  let openInProgress = false
+
   rn_bridge.channel.on('open', async (msg: OpenServices) => {
+    log('Received "open" event via React Native Bridge')
+
+    if (openInProgress) {
+      log('"open" event already being processed, ignoring')
+      return
+    }
+    openInProgress = true
+
     const connectionsManager = app.get<ConnectionsManagerService>(ConnectionsManagerService)
     const torControl = app.get<TorControl>(TorControl)
     const proxyAgent = app.get<{ proxy: { port: string } }>(SOCKS_PROXY_AGENT)
@@ -124,6 +138,8 @@ export const runBackendMobile = async () => {
     proxyAgent.proxy.port = msg.httpTunnelPort
 
     await connectionsManager.openSocket()
+
+    openInProgress = false
   })
 }
 
diff --git a/packages/backend/src/nest/connections-manager/connections-manager.service.ts b/packages/backend/src/nest/connections-manager/connections-manager.service.ts
index f52de0f6bb..8c7291133b 100644
--- a/packages/backend/src/nest/connections-manager/connections-manager.service.ts
+++ b/packages/backend/src/nest/connections-manager/connections-manager.service.ts
@@ -249,6 +249,11 @@ export class ConnectionsManagerService extends EventEmitter implements OnModuleI
   // This method is only used on iOS through rn-bridge for reacting on lifecycle changes
   public async openSocket() {
     await this.socketService.init()
+    await this.libp2pService?.redialPeers()
+
+    // Tried to restart libp2p as another alternative, but received this:
+    // Error: Handler already registered for protocol /meshsub/1.1.0
+    await this.libp2pService?.restart()
   }
 
   public async leaveCommunity() {
diff --git a/packages/backend/src/nest/libp2p/libp2p.service.ts b/packages/backend/src/nest/libp2p/libp2p.service.ts
index c4129e9888..0f29b04eb8 100644
--- a/packages/backend/src/nest/libp2p/libp2p.service.ts
+++ b/packages/backend/src/nest/libp2p/libp2p.service.ts
@@ -32,6 +32,7 @@ export class Libp2pService extends EventEmitter {
   public connectedPeers: Map<string, number> = new Map()
   public dialedPeers: Set<string> = new Set()
   private readonly logger = Logger(Libp2pService.name)
+
   constructor(
     @Inject(SERVER_IO_PROVIDER) public readonly serverIoProvider: ServerIoProviderTypes,
     @Inject(SOCKS_PROXY_AGENT) public readonly socksProxyAgent: Agent,
@@ -40,14 +41,47 @@ export class Libp2pService extends EventEmitter {
     super()
   }
 
+  public restart = async () => {
+    await this.libp2pInstance?.stop()
+    await this.libp2pInstance?.start()
+  }
+
   private dialPeer = async (peerAddress: string) => {
     if (this.dialedPeers.has(peerAddress)) {
       return
     }
     this.dialedPeers.add(peerAddress)
+    console.log('Dialing peer:', peerAddress, this.dialedPeers)
     await this.libp2pInstance?.dial(multiaddr(peerAddress))
   }
 
+  private hangUpPeer = async (peerAddress: string) => {
+    this.logger('Hanging up on peer:', peerAddress)
+    await this.libp2pInstance?.hangUp(multiaddr(peerAddress))
+    this.dialedPeers.delete(peerAddress)
+  }
+
+  /**
+   * Hang up existing peer connections and re-dial them. Specifically useful on
+   * iOS where Tor receives a new port when the app resumes from background and
+   * we want to close/re-open connections.
+   */
+  public redialPeers = async () => {
+    this.logger('Re-dialing peers')
+
+    // TODO: Sort peers
+    const dialedPeers = Array.from(this.dialedPeers)
+
+    for (const peerAddress of dialedPeers) {
+      await this.hangUpPeer(peerAddress)
+    }
+
+    console.log('DIALED PEERS', dialedPeers, this.dialedPeers)
+
+    this.processInChunksService.updateData(dialedPeers)
+    await this.processInChunksService.process()
+  }
+
   public readonly createLibp2pAddress = (address: string, peerId: string): string => {
     return createLibp2pAddress(address, peerId)
   }