96 lines
4.1 KiB
Swift
96 lines
4.1 KiB
Swift
import PromiseKit
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@objc(LKLongPoller)
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public final class LokiLongPoller : NSObject {
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private let onMessagesReceived: ([SSKProtoEnvelope]) -> Void
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private let storage = OWSPrimaryStorage.shared()
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private var hasStarted = false
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private var hasStopped = false
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private var connections = Set<Promise<Void>>()
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private var usedSnodes = Set<LokiAPITarget>()
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// MARK: Settings
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private let connectionCount = 3
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private let retryInterval: TimeInterval = 4
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// MARK: Convenience
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private var userHexEncodedPublicKey: String { return getUserHexEncodedPublicKey() }
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// MARK: Initialization
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@objc public init(onMessagesReceived: @escaping ([SSKProtoEnvelope]) -> Void) {
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self.onMessagesReceived = onMessagesReceived
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super.init()
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}
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// MARK: Public API
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@objc public func startIfNeeded() {
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guard !hasStarted else { return }
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print("[Loki] Started long polling.")
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hasStarted = true
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hasStopped = false
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openConnections()
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}
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@objc public func stopIfNeeded() {
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guard !hasStopped else { return }
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print("[Loki] Stopped long polling.")
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hasStarted = false
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hasStopped = true
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usedSnodes.removeAll()
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}
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// MARK: Private API
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private func openConnections() {
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guard !hasStopped else { return }
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LokiAPI.getSwarm(for: userHexEncodedPublicKey).then(on: DispatchQueue.global()) { [weak self] _ -> Guarantee<[Result<Void>]> in
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guard let strongSelf = self else { return Guarantee.value([Result<Void>]()) }
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strongSelf.usedSnodes.removeAll()
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let connections: [Promise<Void>] = (0..<strongSelf.connectionCount).map { _ in
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let (promise, seal) = Promise<Void>.pending()
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strongSelf.openConnectionToNextSnode(seal: seal)
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return promise
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}
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strongSelf.connections = Set(connections)
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return when(resolved: connections)
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}.ensure(on: DispatchQueue.global()) { [weak self] in
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guard let strongSelf = self else { return }
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Timer.scheduledTimer(withTimeInterval: strongSelf.retryInterval, repeats: false) { _ in
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guard let strongSelf = self else { return }
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strongSelf.openConnections()
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}
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}
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}
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private func openConnectionToNextSnode(seal: Resolver<Void>) {
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let swarm = LokiAPI.swarmCache[userHexEncodedPublicKey] ?? []
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let userHexEncodedPublicKey = self.userHexEncodedPublicKey
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let unusedSnodes = Set(swarm).subtracting(usedSnodes)
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if !unusedSnodes.isEmpty {
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let nextSnode = unusedSnodes.randomElement()!
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usedSnodes.insert(nextSnode)
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print("[Loki] Opening long polling connection to \(nextSnode).")
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longPoll(nextSnode, seal: seal).catch(on: LokiAPI.errorHandlingQueue) { [weak self] error in
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print("[Loki] Long polling connection to \(nextSnode) failed; dropping it and switching to next snode.")
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LokiAPI.dropIfNeeded(nextSnode, hexEncodedPublicKey: userHexEncodedPublicKey)
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self?.openConnectionToNextSnode(seal: seal)
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}
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} else {
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seal.fulfill(())
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}
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}
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private func longPoll(_ target: LokiAPITarget, seal: Resolver<Void>) -> Promise<Void> {
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return LokiAPI.getRawMessages(from: target, usingLongPolling: true).then(on: DispatchQueue.global()) { [weak self] rawResponse -> Promise<Void> in
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guard let strongSelf = self, !strongSelf.hasStopped else { return Promise.value(()) }
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let messages = LokiAPI.parseRawMessagesResponse(rawResponse, from: target)
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let hexEncodedPublicKeys = Set(messages.compactMap { $0.source })
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let promises = hexEncodedPublicKeys.map { LokiAPI.getDestinations(for: $0) }
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return when(resolved: promises).then(on: DispatchQueue.global()) { _ -> Promise<Void> in
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guard let strongSelf = self, !strongSelf.hasStopped else { return Promise.value(()) }
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strongSelf.onMessagesReceived(messages)
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return strongSelf.longPoll(target, seal: seal)
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}
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}
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}
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}
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