Throw proper errors instead of Strings. Documentation fixes.

FullStackTests/Tests/ConnectionFullStackTests.swift

@@ -77,7 +77,7 @@ class ConnectionFullStackTests: XCTestCase {
                 XCTAssertNotNil(secondConnection)
                 let closingError = await task.value
                 XCTAssertNil(closingError)
-                print("✅ connectionDidClose() returned: \(closingError ?? "nil")")
+                print("✅ connectionDidClose() returned: \(String(describing: closingError))")
             } catch {
                 XCTFail("🚨 Failed with: \(error)")
             }

FullStackTests/Tests/ManagementFullStackTests.swift

@@ -30,13 +30,16 @@ class ManagementFullStackTests: XCTestCase {
     }
 
     func testGetDeviceInfo() throws {
-        runManagementTest { _, session, _ in
+        runManagementTest { connection, session, _ in
             let info = try await session.getDeviceInfo()
             print(info)
             print("PIV enabled over usb: \(info.config.isApplicationEnabled(.piv, overTransport: .usb))")
             print("PIV enabled over nfc: \(info.config.isApplicationEnabled(.piv, overTransport: .nfc))")
             print("PIV supported over usb: \(info.isApplicationSupported(.piv, overTransport: .usb))")
             print("PIV supported over nfc: \(info.isApplicationSupported(.piv, overTransport: .nfc))")
+            #if os(iOS)
+            await connection.nfcConnection?.close(message: "Test successful!")
+            #endif
         }
     }
 

YubiKit/YubiKit/Connection.swift

@@ -78,3 +78,17 @@ extension InternalConnection {
     }
 }
 
+/// Connection Errors.
+public enum ConnectionError: Error {
+    /// No current connection.
+    case noConnection
+    /// Unexpected result returned from YubiKey.
+    case unexpectedResult
+    /// YubiKey did not return any data.
+    case missingResult
+    /// Awaiting call to connect() was cancelled.
+    case cancelled
+    /// Connection was closed.
+    case closed
+}
+

YubiKit/YubiKit/LightningConnection.swift

@@ -78,15 +78,15 @@ public final actor LightningConnection: Connection, InternalConnection {
     }
 
     internal func send(apdu: APDU) async throws -> Response {
-        guard let accessoryConnection, let outputStream = accessoryConnection.session.outputStream, let inputStream = accessoryConnection.session.inputStream else { throw "No current session" }
+        guard let accessoryConnection, let outputStream = accessoryConnection.session.outputStream, let inputStream = accessoryConnection.session.inputStream else { throw ConnectionError.noConnection }
         var data = Data([0x00]) // YLP iAP2 Signal
         data.append(apdu.data)
 
         try outputStream.writeToYubiKey(data: data)
         while true {
             try await Task.sleep(for: .seconds(commandProcessingTime))
             let result = try inputStream.readFromYubiKey()
-            if result.isEmpty { throw "Empty result" }
+            if result.isEmpty { throw ConnectionError.missingResult }
             let status = Response.StatusCode(data: result.subdata(in: result.count-2..<result.count))
 
             // BUG #62 - Workaround for WTX == 0x01 while status is 0x9000 (success).
@@ -96,7 +96,7 @@ public final actor LightningConnection: Connection, InternalConnection {
                 } else if result.bytes[0] == 0x01 { // Remove the YLP key protocol header and the WTX
                     return Response(rawData: result.subdata(in: 4..<result.count))
                 }
-                throw "Wrong response"
+                throw ConnectionError.unexpectedResult
             }
         }
     }
@@ -221,9 +221,9 @@ fileprivate class EAAccessoryWrapper: NSObject, StreamDelegate {
         queue.async {
             // Signal closure and cancel previous connection handlers
             // Swap out old handlers to the new ones
-            self.closingHandler?("Closed by new call to connection()")
+            self.closingHandler?(ConnectionError.closed)
             self.closingHandler = nil
-            self.connectingHandler?(.failure("⚡️ Cancelled by new call to connection()"))
+            self.connectingHandler?(.failure(ConnectionError.cancelled))
             self.connectingHandler = handler
 
             if self.state == .ready {
@@ -306,10 +306,10 @@ fileprivate class EAAccessoryWrapper: NSObject, StreamDelegate {
                 break;
             case .scanning:
                 // should we call the closingHandler as well?
-                self.connectingHandler?(.failure("Cancelled from stop()"))
+                self.connectingHandler?(.failure(ConnectionError.cancelled))
             case .connected(let connection):
                 connection.close()
-                self.closingHandler?("Closed by user")
+                self.closingHandler?(ConnectionError.closed)
             }
             self.connectingHandler = nil
             self.closingHandler = nil

YubiKit/YubiKit/NFCConnection.swift

@@ -101,8 +101,8 @@ public final actor NFCConnection: Connection, InternalConnection {
     }
 
     internal func send(apdu: APDU) async throws -> Response {
-        guard let tag else { throw "No NFC tag" }
-        guard let apdu = apdu.nfcIso7816Apdu else { throw "Malformed APDU data" }
+        guard let tag else { throw ConnectionError.noConnection }
+        guard let apdu = apdu.nfcIso7816Apdu else { throw NFCConnectionError.malformedAPDU }
         let result: (Data, UInt8, UInt8) = try await tag.sendCommand(apdu: apdu)
         return Response(data: result.0, sw1: result.1, sw2: result.2)
     }
@@ -207,9 +207,9 @@ fileprivate class NFCTagWrapper: NSObject, NFCTagReaderSessionDelegate {
 
     internal func connection(alertMessage message: String?, completion handler: @escaping (Result<TagReaderSession, Error>) -> Void) {
         queue.async {
-            self.closingHandler?("Closed by new call to connection()")
+            self.closingHandler?(ConnectionError.closed)
             self.closingHandler = nil
-            self.connectingHandler?(.failure("Cancelled by new call to connection()"))
+            self.connectingHandler?(.failure(ConnectionError.cancelled))
             self.connectingHandler = handler
 
             switch self.state {
@@ -288,14 +288,23 @@ fileprivate class NFCTagWrapper: NSObject, NFCTagReaderSessionDelegate {
                     self.connectingHandler?(.success(session))
                 } else {
                     Logger.nfc.debug("Failed connecting to \(String(describing: tag)) since it's not a iso7816 tag.")
-                    self.connectingHandler?(.failure("Not an iso7816 tag!"))
+                    self.connectingHandler?(.failure(NFCConnectionError.noISO7816Tag))
                 }
                 self.connectingHandler = nil
             }
         }
     }
 }
 
+
+/// NFCConnection specific errors.
+public enum NFCConnectionError: Error {
+    /// The tag you are trying to connect to is not a ISO7816 tag.
+    case noISO7816Tag
+    /// The APDU you are trying to send to the YubiKey over NFC is malformed.
+    case malformedAPDU
+}
+
 extension Connection {
     /// Returns a NFCConnection if the connection is a NFCConnection. This is useful since NFCConnections need to be
     /// closed as soon as you are done sending commands to them while wired connections are usually kept alive.

YubiKit/YubiKit/SmartCardConnection.swift

@@ -76,7 +76,7 @@ public final actor SmartCardConnection: Connection, InternalConnection {
     }
 
     internal func send(apdu: APDU) async throws -> Response {
-        guard let smartCard else { throw "No SmartCard connection" }
+        guard let smartCard else { throw ConnectionError.noConnection }
         let data = try await smartCard.transmit(apdu.data)
         return Response(rawData: data)
     }
@@ -178,9 +178,9 @@ fileprivate class TKSmartCardWrapper {
         queue.async {
             // Signal closure and cancel previous connection handlers
             // Swap out old handlers to the new ones
-            self.closingHandler?("Closed by new call to connection()")
+            self.closingHandler?(ConnectionError.closed)
             self.closingHandler = nil
-            self.connectingHandler?(.failure("🪪 Cancelled by new call to connection()"))
+            self.connectingHandler?(.failure(ConnectionError.cancelled))
             self.connectingHandler = handler
 
             // If we're currently not monitoring or initating a session
@@ -230,7 +230,7 @@ fileprivate class TKSmartCardWrapper {
                         manager.getSlot(withName: slotName) { slot in
                             guard let slot else {
                                 self.state = .ready
-                                self.connectingHandler?(.failure("Failed to get a TKSmartCardSlot from TKSmartCardSlotManager."))
+                                self.connectingHandler?(.failure(SmartCardConnectionError.getSmartCardSlotFailed))
                                 self.connectingHandler = nil
                                 return
                             }
@@ -286,7 +286,7 @@ fileprivate class TKSmartCardWrapper {
                             self?.observeKeyRemoval()
                         } else {
                             self?.state = .ready
-                            self?.connectingHandler?(.failure("🪪 Failed but got no error!"))
+                            self?.connectingHandler?(.failure(SmartCardConnectionError.beginSessionFailed))
                             self?.connectingHandler = nil
                         }
                     }
@@ -303,10 +303,10 @@ fileprivate class TKSmartCardWrapper {
                 break;
             case .monitoring, .initatingSession:
                 // should we call the closingHandler as well?
-                self.connectingHandler?(.failure("Cancelled from stop()"))
+                self.connectingHandler?(.failure(ConnectionError.cancelled))
             case .connected(let session):
                 session.endSession()
-                self.closingHandler?("Closed by user")
+                self.closingHandler?(ConnectionError.closed)
             }
             self.state = .ready
             self.connectingHandler = nil
@@ -318,3 +318,11 @@ fileprivate class TKSmartCardWrapper {
         }
     }
 }
+
+/// SmartCardConnection specific errors
+public enum SmartCardConnectionError: Error {
+    /// CryptoTokenKit failed to return a TKSmartCardSlot.
+    case getSmartCardSlotFailed
+    /// CryptoTokenKit failed to start a session for the TKSmartCard.
+    case beginSessionFailed
+}

YubiKit/YubiKit/YubiKit.docc/Resources/ConnectionExtension.md

@@ -19,3 +19,7 @@
 ### Sending data to the YubiKey
 
 - ``send(apdu:)``
+
+### Errors
+
+- ``ConnectionError``

YubiKit/YubiKit/YubiKit.docc/Resources/ManagementSessionExtension.md

@@ -10,7 +10,6 @@
 
 - ``session(withConnection:)``
 - ``end()``
-- ``sessionDidEnd()``
 
 ### Running commands in the Management application
 

YubiKit/YubiKit/YubiKit.docc/Resources/NFCConnectionExtension.md

@@ -22,3 +22,7 @@
 ### Sending data to the YubiKey
 
 - ``Connection/send(apdu:)``
+
+### Errors
+
+- ``NFCConnectionError``

YubiKit/YubiKit/YubiKit.docc/Resources/OATHSessionExtension.md

@@ -11,7 +11,6 @@
 - ``session(withConnection:)``
 - ``end()``
 - ``reset()``
-- ``sessionDidEnd()``
 
 ### Running commands in the OATH application
 

YubiKit/YubiKit/YubiKit.docc/Resources/SmartCardConnectionExtension.markdown → YubiKit/YubiKit/YubiKit.docc/Resources/SmartCardConnectionExtension.md

@@ -18,3 +18,7 @@
 ### Sending data to the YubiKey
 
 - ``Connection/send(apdu:)``
+
+### Errors
+
+- ``SmartCardConnectionError``