chore(repo): Clean up workers

Force unwrapping nullable values is done in JS by calling `nullableValue.toString` which will throw an error if `nullableValue` is null. Browsers seem to handle this sort of error different than a thrown Dart error and the error is harder to trace when it happens.

Introduces an `unwrapParameter` method to the base worker bee class so that unwrap errors are strongly-typed and provide more context to the issue.

packages/auth/amplify_auth_cognito_dart/lib/src/flows/device/confirm_device_worker.dart

@@ -77,8 +77,9 @@ abstract class ConfirmDeviceWorker
     StreamSink<ConfirmDeviceResponse> respond,
   ) async {
     await for (final message in listen) {
-      final deviceGroupKey = message.newDeviceMetadata.deviceGroupKey;
-      final deviceKey = message.newDeviceMetadata.deviceKey;
+      final ConfirmDeviceMessage(:newDeviceMetadata, :accessToken) = message;
+      final deviceGroupKey = newDeviceMetadata.deviceGroupKey;
+      final deviceKey = newDeviceMetadata.deviceKey;
       if (deviceGroupKey == null || deviceKey == null) {
         throw InvalidParameterException(message: 'Missing device metadata');
       }
@@ -100,7 +101,7 @@ abstract class ConfirmDeviceWorker
       );
       final request = ConfirmDeviceRequest.build((b) {
         b
-          ..accessToken = message.accessToken
+          ..accessToken = accessToken
           ..deviceKey = deviceKey
           ..deviceSecretVerifierConfig.passwordVerifier =
               base64Encode(encodeBigInt(verifier))

packages/auth/amplify_auth_cognito_dart/lib/src/flows/srp/srp_device_password_verifier_worker.dart

@@ -9,7 +9,6 @@ import 'package:amplify_auth_cognito_dart/src/flows/srp/srp_device_password_veri
 import 'package:amplify_auth_cognito_dart/src/flows/srp/srp_helper.dart';
 import 'package:amplify_auth_cognito_dart/src/flows/srp/srp_init_result.dart';
 import 'package:amplify_auth_cognito_dart/src/model/cognito_device_secrets.dart';
-import 'package:amplify_auth_cognito_dart/src/model/sign_in_parameters.dart';
 import 'package:amplify_auth_cognito_dart/src/sdk/cognito_identity_provider.dart';
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/built_value.dart';
@@ -46,9 +45,6 @@ abstract class SrpDevicePasswordVerifierMessage
   /// User device secrets.
   CognitoDeviceSecrets get deviceSecrets;
 
-  /// Parameters to the SRP flow.
-  SignInParameters get parameters;
-
   /// Parameters of the current challenge.
   BuiltMap<String, String> get challengeParameters;
 
@@ -78,48 +74,63 @@ abstract class SrpDevicePasswordVerifierWorker extends WorkerBeeBase<
     StreamSink<RespondToAuthChallengeRequest> respond,
   ) async {
     await for (final message in listen) {
-      final username =
-          message.challengeParameters[CognitoConstants.challengeParamUsername]!;
-      final deviceKey = message
-          .challengeParameters[CognitoConstants.challengeParamDeviceKey]!;
-      final secretBlock = message
-          .challengeParameters[CognitoConstants.challengeParamSecretBlock]!;
-      final encodedSalt =
-          message.challengeParameters[CognitoConstants.challengeParamSalt]!;
-      final encodedB =
-          message.challengeParameters[CognitoConstants.challengeParamSrpB]!;
-      final timestamp = DateTime.now().toUtc();
-      final formattedTimestamp = _dateFormat.format(timestamp);
+      final SrpDevicePasswordVerifierMessage(
+        :initResult,
+        :clientId,
+        :clientSecret,
+        :deviceSecrets,
+        :challengeParameters,
+      ) = message;
+      final username = unwrapParameter(
+        CognitoConstants.challengeParamUsername,
+        challengeParameters[CognitoConstants.challengeParamUsername],
+      );
+      final deviceKey = unwrapParameter(
+        CognitoConstants.challengeParamDeviceKey,
+        challengeParameters[CognitoConstants.challengeParamDeviceKey],
+      );
+      final secretBlock = unwrapParameter(
+        CognitoConstants.challengeParamSecretBlock,
+        challengeParameters[CognitoConstants.challengeParamSecretBlock],
+      );
+      final encodedSalt = unwrapParameter(
+        CognitoConstants.challengeParamSalt,
+        challengeParameters[CognitoConstants.challengeParamSalt],
+      );
+      final encodedB = unwrapParameter(
+        CognitoConstants.challengeParamSrpB,
+        challengeParameters[CognitoConstants.challengeParamSrpB],
+      );
+      final formattedTimestamp = _dateFormat.format(DateTime.timestamp());
 
       final encodedClaim = SrpHelper.createDeviceClaim(
         deviceKey: deviceKey,
-        deviceSecrets: message.deviceSecrets,
+        deviceSecrets: deviceSecrets,
         username: username,
-        initResult: message.initResult,
+        initResult: initResult,
         encodedSalt: encodedSalt,
         encodedB: encodedB,
         secretBlock: secretBlock,
         formattedTimestamp: formattedTimestamp,
       );
       final response = RespondToAuthChallengeRequest.build((b) {
         b
-          ..clientId = message.clientId
+          ..clientId = clientId
           ..challengeName = ChallengeNameType.devicePasswordVerifier
-          ..challengeResponses.addAll({
-            CognitoConstants.challengeParamPasswordSecretBlock: secretBlock,
-            CognitoConstants.challengeParamPasswordSignature: encodedClaim,
-            CognitoConstants.challengeParamUsername: username,
-            CognitoConstants.challengeParamTimestamp: formattedTimestamp,
-            CognitoConstants.challengeParamDeviceKey: deviceKey,
-          });
-
-        if (message.clientSecret != null) {
+          ..challengeResponses[
+              CognitoConstants.challengeParamPasswordSecretBlock] = secretBlock
+          ..challengeResponses[
+              CognitoConstants.challengeParamPasswordSignature] = encodedClaim
+          ..challengeResponses[CognitoConstants.challengeParamUsername] =
+              username
+          ..challengeResponses[CognitoConstants.challengeParamTimestamp] =
+              formattedTimestamp
+          ..challengeResponses[CognitoConstants.challengeParamDeviceKey] =
+              deviceKey;
+
+        if (clientSecret != null) {
           b.challengeResponses[CognitoConstants.challengeParamSecretHash] =
-              computeSecretHash(
-            username,
-            message.clientId,
-            message.clientSecret!,
-          );
+              computeSecretHash(username, clientId, clientSecret);
         }
       });
 

packages/auth/amplify_auth_cognito_dart/lib/src/flows/srp/srp_init_worker.dart

@@ -44,7 +44,6 @@ abstract class SrpInitWorker
     Stream<SrpInitMessage> listen,
     StreamSink<SrpInitResult> respond,
   ) async {
-    // ignore: no_leading_underscores_for_local_identifiers
     await for (final _ in listen) {
       respond.add(SrpHelper.deriveEphemeralValues());
     }

packages/auth/amplify_auth_cognito_dart/lib/src/flows/srp/srp_password_verifier_worker.dart

@@ -33,7 +33,7 @@ abstract class SrpPasswordVerifierMessage
 
   @BuiltValueHook(finalizeBuilder: true)
   static void _init(SrpPasswordVerifierMessageBuilder b) {
-    b.timestamp ??= DateTime.now().toUtc();
+    b.timestamp ??= DateTime.timestamp();
   }
 
   /// Result of the SRP initialization step.
@@ -85,25 +85,45 @@ abstract class SrpPasswordVerifierWorker extends WorkerBeeBase<
     StreamSink<RespondToAuthChallengeRequest> respond,
   ) async {
     await for (final message in listen) {
-      final username =
-          message.challengeParameters[CognitoConstants.challengeParamUsername]!;
-      final userId = message
-          .challengeParameters[CognitoConstants.challengeParamUserIdForSrp]!;
+      final SrpPasswordVerifierMessage(
+        :initResult,
+        :clientId,
+        :clientSecret,
+        :poolId,
+        :deviceKey,
+        :parameters,
+        :challengeParameters,
+        :timestamp,
+      ) = message;
+      final username = unwrapParameter(
+        CognitoConstants.challengeParamUsername,
+        challengeParameters[CognitoConstants.challengeParamUsername],
+      );
+      final userId = unwrapParameter(
+        CognitoConstants.challengeParamUserIdForSrp,
+        challengeParameters[CognitoConstants.challengeParamUserIdForSrp],
+      );
+      final secretBlock = unwrapParameter(
+        CognitoConstants.challengeParamSecretBlock,
+        challengeParameters[CognitoConstants.challengeParamSecretBlock],
+      );
+      final encodedSalt = unwrapParameter(
+        CognitoConstants.challengeParamSalt,
+        challengeParameters[CognitoConstants.challengeParamSalt],
+      );
+      final encodedB = unwrapParameter(
+        CognitoConstants.challengeParamSrpB,
+        challengeParameters[CognitoConstants.challengeParamSrpB],
+      );
+
       // Pool ID is in the form `{region}_{poolName}`
-      final poolName = message.poolId.split('_')[1];
-      final secretBlock = message
-          .challengeParameters[CognitoConstants.challengeParamSecretBlock]!;
-      final encodedSalt =
-          message.challengeParameters[CognitoConstants.challengeParamSalt]!;
-      final encodedB =
-          message.challengeParameters[CognitoConstants.challengeParamSrpB]!;
-      final timestamp = message.timestamp;
+      final poolName = poolId.split('_')[1];
       final formattedTimestamp = _dateFormat.format(timestamp);
 
       final encodedClaim = SrpHelper.createPasswordClaim(
         userId: userId,
-        parameters: message.parameters,
-        initResult: message.initResult,
+        parameters: parameters,
+        initResult: initResult,
         encodedSalt: encodedSalt,
         encodedB: encodedB,
         poolName: poolName,
@@ -112,25 +132,21 @@ abstract class SrpPasswordVerifierWorker extends WorkerBeeBase<
       );
       final response = RespondToAuthChallengeRequest.build((b) {
         b
-          ..clientId = message.clientId
+          ..clientId = clientId
           ..challengeName = ChallengeNameType.passwordVerifier
-          ..challengeResponses.addAll({
-            CognitoConstants.challengeParamPasswordSecretBlock: secretBlock,
-            CognitoConstants.challengeParamPasswordSignature: encodedClaim,
-            CognitoConstants.challengeParamUsername: username,
-            CognitoConstants.challengeParamTimestamp: formattedTimestamp,
-          });
-
-        if (message.clientSecret != null) {
+          ..challengeResponses[
+              CognitoConstants.challengeParamPasswordSecretBlock] = secretBlock
+          ..challengeResponses[
+              CognitoConstants.challengeParamPasswordSignature] = encodedClaim
+          ..challengeResponses[CognitoConstants.challengeParamUsername] =
+              username
+          ..challengeResponses[CognitoConstants.challengeParamTimestamp] =
+              formattedTimestamp;
+
+        if (clientSecret != null) {
           b.challengeResponses[CognitoConstants.challengeParamSecretHash] =
-              computeSecretHash(
-            username,
-            message.clientId,
-            message.clientSecret!,
-          );
+              computeSecretHash(username, clientId, clientSecret);
         }
-
-        final deviceKey = message.deviceKey;
         if (deviceKey != null) {
           b.challengeResponses[CognitoConstants.challengeParamDeviceKey] =
               deviceKey;

packages/auth/amplify_auth_cognito_dart/lib/src/state/machines/sign_in_state_machine.dart

@@ -426,8 +426,7 @@ final class SignInStateMachine
         ..initResult = _initResult
         ..clientId = config.appClientId
         ..clientSecret = config.appClientSecret
-        ..challengeParameters = BuiltMap(_publicChallengeParameters)
-        ..parameters = parameters;
+        ..challengeParameters = BuiltMap(_publicChallengeParameters);
     });
     worker.sink.add(workerMessage);
     return worker.stream.first;

packages/auth/amplify_auth_cognito_test/test/flows/srp/srp_device_password_verifier_worker_test.dart

@@ -6,7 +6,6 @@ import 'dart:async';
 import 'package:amplify_auth_cognito_dart/src/flows/constants.dart';
 import 'package:amplify_auth_cognito_dart/src/flows/srp/srp_device_password_verifier_worker.dart';
 import 'package:amplify_auth_cognito_dart/src/model/cognito_device_secrets.dart';
-import 'package:amplify_auth_cognito_dart/src/model/sign_in_parameters.dart';
 import 'package:amplify_auth_cognito_dart/src/sdk/src/cognito_identity_provider/model/respond_to_auth_challenge_request.dart';
 import 'package:amplify_auth_cognito_test/common/mock_config.dart'
     hide username;
@@ -38,11 +37,6 @@ void main() {
               ..deviceGroupKey = deviceGroupKey
               ..devicePassword = devicePassword,
           )
-          ..parameters = SignInParameters(
-            (p) => p
-              ..username = srpUsername
-              ..password = srpPassword,
-          )
           ..challengeParameters = BuiltMap({
             CognitoConstants.challengeParamUsername: srpUsername,
             CognitoConstants.challengeParamUserIdForSrp: srpUsername,
@@ -82,11 +76,7 @@ void main() {
               ..deviceGroupKey = deviceGroupKey
               ..devicePassword = devicePassword,
           )
-          ..parameters = SignInParameters(
-            (p) => p
-              ..username = srpUsername
-              ..password = srpPassword,
-          )
+          // No challenge parameters
           ..challengeParameters = BuiltMap(<String, String>{}),
       );
       worker.add(message);