Merge pull request #339 from pusher/tech/refactor-private-api

Refactoring the private API

Author: danielrbrowne

PusherSwift.xcodeproj/project.pbxproj

@@ -0,0 +1,28 @@
+import Foundation
+
+extension PusherChannel {
+
+    /// Determines whether or not a message should be decrypted, based on channel and event attributes.
+    /// - Parameters:
+    ///   - name: The name of the channel.
+    ///   - eventName: The name of the event received on the channel.
+    /// - Returns: A `Bool` indicating whether the message should be decrypted or not.
+    static func decryptsMessage(name: String?, eventName: String) -> Bool {
+        return isEncrypted(name: name) && !isSystemEvent(eventName: eventName)
+    }
+
+    /// Determines if a channel is a private encrypted or not, based on its name.
+    /// - Parameter name: The name of the channel.
+    /// - Returns: A `Bool` indicating whether the channel is encrypted or not.
+    static func isEncrypted(name: String?) -> Bool {
+        return name?.starts(with: "\(Constants.ChannelTypes.privateEncrypted)-") ?? false
+    }
+
+    /// Determines if an event is a system event or not, based on its name.
+    /// - Parameter eventName: The name of the event.
+    /// - Returns: A `Bool` indicating whether the event is a system event or not.
+    private static func isSystemEvent(eventName: String) -> Bool {
+        return eventName.starts(with: "\(Constants.EventTypes.pusher):")
+            || eventName.starts(with: "\(Constants.EventTypes.pusherInternal):")
+    }
+}

Sources/Extensions/PusherChannel+EncryptionHelpers.swift

@@ -11,20 +11,20 @@ extension PusherConnection: WebSocketConnectionDelegate {
         - parameter string: The message received over the websocket
     */
     public func webSocketDidReceiveMessage(connection: WebSocketConnection, string: String) {
-        PusherLogger.shared.debug(for: .receivedMessage, context: string)
+        Logger.shared.debug(for: .receivedMessage, context: string)
 
-        guard let payload = PusherParser.getPusherEventJSON(from: string),
+        guard let payload = EventParser.getPusherEventJSON(from: string),
             let event = payload[Constants.JSONKeys.event] as? String
         else {
-            PusherLogger.shared.debug(for: .unableToHandleIncomingMessage,
-                                      context: string)
+            Logger.shared.debug(for: .unableToHandleIncomingMessage,
+                                context: string)
             return
         }
 
         if event == Constants.Events.Pusher.error {
             guard let error = PusherError(jsonObject: payload) else {
-                PusherLogger.shared.debug(for: .unableToHandleIncomingError,
-                                          context: string)
+                Logger.shared.debug(for: .unableToHandleIncomingError,
+                                    context: string)
                 return
             }
             self.handleError(error: error)
@@ -36,7 +36,7 @@ extension PusherConnection: WebSocketConnectionDelegate {
     /// Delegate method called when a pong is received over a websocket
     /// - Parameter connection: The websocket that has received the pong
     public func webSocketDidReceivePong(connection: WebSocketConnection) {
-        PusherLogger.shared.debug(for: .pongReceived)
+        Logger.shared.debug(for: .pongReceived)
         resetActivityTimeoutTimer()
     }
 
@@ -64,7 +64,7 @@ extension PusherConnection: WebSocketConnectionDelegate {
         updateConnectionState(to: .disconnected)
 
         guard !intentionalDisconnect else {
-            PusherLogger.shared.debug(for: .intentionalDisconnection)
+            Logger.shared.debug(for: .intentionalDisconnection)
             return
         }
 
@@ -82,7 +82,7 @@ extension PusherConnection: WebSocketConnectionDelegate {
         }
 
         guard reconnectAttemptsMax == nil || reconnectAttempts < reconnectAttemptsMax! else {
-            PusherLogger.shared.debug(for: .maxReconnectAttemptsLimitReached)
+            Logger.shared.debug(for: .maxReconnectAttemptsLimitReached)
             return
         }
 
@@ -91,9 +91,9 @@ extension PusherConnection: WebSocketConnectionDelegate {
 
     public func webSocketViabilityDidChange(connection: WebSocketConnection, isViable: Bool) {
         if isViable {
-            PusherLogger.shared.debug(for: .networkConnectionViable)
+            Logger.shared.debug(for: .networkConnectionViable)
         } else {
-            PusherLogger.shared.debug(for: .networkConnectionUnviable)
+            Logger.shared.debug(for: .networkConnectionUnviable)
         }
     }
 
@@ -103,8 +103,8 @@ extension PusherConnection: WebSocketConnectionDelegate {
             updateConnectionState(to: .reconnecting)
 
         case .failure(let error):
-            PusherLogger.shared.debug(for: .errorReceived,
-                                      context: """
+            Logger.shared.debug(for: .errorReceived,
+                                context: """
                 Path migration error: \(error.debugDescription)
                 """)
         }
@@ -128,9 +128,9 @@ extension PusherConnection: WebSocketConnectionDelegate {
 
         // Reconnect attempt according to Pusher Channels Protocol close code (if present).
         // (Otherwise, the default behavior is to attempt reconnection after backing off).
-        var channelsCloseCode: PusherChannelsProtocolCloseCode?
+        var channelsCloseCode: ChannelsProtocolCloseCode?
         if case let .privateCode(code) = closeCode {
-            channelsCloseCode = PusherChannelsProtocolCloseCode(rawValue: code)
+            channelsCloseCode = ChannelsProtocolCloseCode(rawValue: code)
         }
         let strategy = channelsCloseCode?.reconnectionStrategy ?? .reconnectAfterBackingOff
 
@@ -161,7 +161,7 @@ extension PusherConnection: WebSocketConnectionDelegate {
     /// Returns a `TimeInterval` appropriate for a reconnection attempt after some delay.
     /// - Parameter strategy: The reconnection strategy for the reconnection attempt.
     /// - Returns: An appropriate `TimeInterval`. (0.0 if `strategy == .reconnectImmediately`).
-    func reconnectionAttemptTimeInterval(strategy: PusherChannelsProtocolCloseCode.ReconnectionStrategy) -> TimeInterval {
+    func reconnectionAttemptTimeInterval(strategy: ChannelsProtocolCloseCode.ReconnectionStrategy) -> TimeInterval {
         if case .reconnectImmediately = strategy {
             return 0.0
         }
@@ -174,10 +174,10 @@ extension PusherConnection: WebSocketConnectionDelegate {
 
     /// Logs the websocket reconnection attempt.
     /// - Parameter strategy: The reconnection strategy for the reconnection attempt.
-    func logReconnectionAttempt(strategy: PusherChannelsProtocolCloseCode.ReconnectionStrategy) {
+    func logReconnectionAttempt(strategy: ChannelsProtocolCloseCode.ReconnectionStrategy) {
 
         var context = "(attempt \(reconnectAttempts + 1))"
-        var loggingEvent = PusherLogger.LoggingEvent.attemptReconnectionImmediately
+        var loggingEvent = Logger.LoggingEvent.attemptReconnectionImmediately
 
         if reconnectAttemptsMax != nil {
             context.insert(contentsOf: " of \(reconnectAttemptsMax!)", at: context.index(before: context.endIndex))
@@ -189,8 +189,8 @@ extension PusherConnection: WebSocketConnectionDelegate {
             context = "\(timeInterval) seconds " + context
         }
 
-        PusherLogger.shared.debug(for: loggingEvent,
-                                  context: context)
+        Logger.shared.debug(for: loggingEvent,
+                            context: context)
     }
 
     /// Logs the websocket disconnection event.
@@ -218,8 +218,8 @@ extension PusherConnection: WebSocketConnectionDelegate {
             closeMessage += " Reason: \(reasonString)."
         }
 
-        PusherLogger.shared.debug(for: .disconnectionWithoutError,
-                                  context: closeMessage)
+        Logger.shared.debug(for: .disconnectionWithoutError,
+                            context: closeMessage)
     }
 
     /**
@@ -236,8 +236,8 @@ extension PusherConnection: WebSocketConnectionDelegate {
     }
 
     public func webSocketDidReceiveError(connection: WebSocketConnection, error: NWError) {
-        PusherLogger.shared.debug(for: .errorReceived,
-                                  context: """
+        Logger.shared.debug(for: .errorReceived,
+                            context: """
             Error: \(error.debugDescription)
             """)
     }

Sources/Extensions/PusherWebsocketDelegate.swift renamed to Sources/Extensions/PusherConnection+WebsocketDelegate.swift

@@ -0,0 +1,22 @@
+import Foundation
+
+extension URL {
+
+    /// Creates a valid URL string that can be used in a connection attempt.
+    /// - Parameters:
+    ///   - key: The app key to be inserted into the URL.
+    ///   - options: The collection of options needed to correctly construct the URL.
+    /// - Returns: The constructed URL string, ready to use in a connection attempt.
+    static func channelsSocketUrl(key: String, options: PusherClientOptions) -> String {
+        var url = ""
+        let additionalPathComponents = options.path ?? ""
+
+        if options.useTLS {
+            url = "wss://\(options.host):\(options.port)\(additionalPathComponents)/app/\(key)"
+        } else {
+            url = "ws://\(options.host):\(options.port)\(additionalPathComponents)/app/\(key)"
+        }
+
+        return "\(url)?client=\(CLIENT_NAME)&version=\(VERSION)&protocol=\(PROTOCOL)"
+    }
+}

Sources/Extensions/URL+Pusher.swift

@@ -1,20 +1,43 @@
+import CryptoKit
 import Foundation
 import TweetNacl
 
-class PusherDecryptor {
+struct Crypto {
 
     private struct EncryptedData: Decodable {
         let nonce: String
         let ciphertext: String
     }
 
+    // MARK: - Public methods
+
+    /// Generates a SHA256 HMAC digest of the message using the secret.
+    /// - Parameters:
+    ///   - secret: The secret key.
+    ///   - message: The message.
+    /// - Returns: The hex-encoded MAC string.
+    static func generateSHA256HMAC(secret: String, message: String) -> String {
+        let key = SymmetricKey(data: Data(secret.utf8))
+        let signature = HMAC<SHA256>.authenticationCode(for: Data(message.utf8), using: key)
+
+        return signature
+            .map { String(format: "%02hhx", $0) }
+            .joined()
+    }
+
+    /// Decrypts some data `String` using a key, according to the NaCl secret box algorithm.
+    /// - Parameters:
+    ///   - data: A JSON-encoded `String` of base64-encoded nonce and cypher text strings.
+    ///   - decryptionKey: A base64-encoded decryption key `String`.
+    /// - Throws: An `EventError` if the decryption operation fails for some reason.
+    /// - Returns: The decrypted data `String`.
     static func decrypt(data: String?, decryptionKey: String?) throws -> String? {
         guard let data = data else {
             return nil
         }
 
         guard let decryptionKey = decryptionKey else {
-            throw PusherEventError.invalidDecryptionKey
+            throw EventError.invalidDecryptionKey
         }
 
         let encryptedData = try self.encryptedData(fromData: data)
@@ -25,41 +48,43 @@ class PusherDecryptor {
         guard let decryptedData = try? NaclSecretBox.open(box: cipherText,
                                                           nonce: nonce,
                                                           key: secretKey),
-            let decryptedString = String(bytes: decryptedData, encoding: .utf8) else {
-                throw PusherEventError.invalidDecryptionKey
+              let decryptedString = String(bytes: decryptedData, encoding: .utf8) else {
+            throw EventError.invalidDecryptionKey
         }
 
         return decryptedString
     }
 
+    // MARK: - Private methods
+
     private static func encryptedData(fromData data: String) throws -> EncryptedData {
         guard let encodedData = data.data(using: .utf8),
-            let encryptedData = try? JSONDecoder().decode(EncryptedData.self, from: encodedData) else {
-                throw PusherEventError.invalidEncryptedData
+              let encryptedData = try? JSONDecoder().decode(EncryptedData.self, from: encodedData) else {
+            throw EventError.invalidEncryptedData
         }
 
         return encryptedData
     }
 
     private static func decodedCipherText(fromEncryptedData encryptedData: EncryptedData) throws -> Data {
         guard let decodedCipherText = Data(base64Encoded: encryptedData.ciphertext) else {
-            throw PusherEventError.invalidEncryptedData
+            throw EventError.invalidEncryptedData
         }
 
         return decodedCipherText
     }
 
     private static func decodedNonce(fromEncryptedData encryptedData: EncryptedData) throws -> Data {
         guard let decodedNonce = Data(base64Encoded: encryptedData.nonce) else {
-            throw PusherEventError.invalidEncryptedData
+            throw EventError.invalidEncryptedData
         }
 
         return decodedNonce
     }
 
     private static func decodedDecryptionKey(fromDecryptionKey decryptionKey: String) throws -> Data {
         guard let decodedDecryptionKey = Data(base64Encoded: decryptionKey) else {
-            throw PusherEventError.invalidDecryptionKey
+            throw EventError.invalidDecryptionKey
         }
 
         return decodedDecryptionKey

Sources/Services/PusherDecryptor.swift renamed to Sources/Helpers/Crypto.swift

@@ -1,6 +1,6 @@
 import Foundation
 
-struct PusherParser {
+struct EventParser {
 
     /**
      Parse a string to extract Pusher event information from it
@@ -20,12 +20,12 @@ struct PusherParser {
                                                                   options: []) as? [String: AnyObject] {
                 return jsonObject
             } else {
-                PusherLogger.shared.debug(for: .unableToParseStringAsJSON,
-                                          context: string)
+                Logger.shared.debug(for: .unableToParseStringAsJSON,
+                                    context: string)
             }
         } catch let error as NSError {
-            PusherLogger.shared.error(for: .genericError,
-                                      context: error.localizedDescription)
+            Logger.shared.error(for: .genericError,
+                                context: error.localizedDescription)
         }
         return nil
     }
@@ -44,8 +44,8 @@ struct PusherParser {
             if let jsonData = data, let jsonObject = try? JSONSerialization.jsonObject(with: jsonData, options: []) {
                 return jsonObject
             } else {
-                PusherLogger.shared.debug(for: .unableToParseStringAsJSON,
-                                          context: string)
+                Logger.shared.debug(for: .unableToParseStringAsJSON,
+                                    context: string)
             }
         }
         return nil

Sources/Helpers/PusherParser.swift renamed to Sources/Helpers/EventParser.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 /// Used for logging events for informational purposes
-class PusherLogger {
+class Logger {
 
     // MARK: - Enum definitions
 
@@ -68,7 +68,7 @@ class PusherLogger {
         case error      = "[PUSHER ERROR]"
     }
 
-    static let shared = PusherLogger()
+    static let shared = Logger()
 
     weak var delegate: PusherDelegate?