amazon_cognito_identity_dart 0.0.10

Unofficial Amazon Cognito Identity Provider Dart SDK, to easily add user sign-up and sign-in to your mobile and web apps with AWS Cloud Services.

Amazon Cognito Identity SDK for Dart

Unofficial Amazon Cognito Identity SDK written in Dart for Dart.

Rewrite of amazon-cognito-identity-js in Dart.

Please note that this package is not production ready.

Usage

Use Case 1. Registering a user with the application. One needs to create a CognitoUserPool object by providing a UserPoolId and a ClientId and signing up by using a username, password, attribute list, and validation data.

import 'package:amazon_cognito_identity_dart/cognito.dart';

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx');
final userAttributes = [
  new AttributeArg(name: 'first_name', value: 'Jimmy'),
  new AttributeArg(name: 'last_name', value: 'Wong'),
];

var data;
try {
  data = await userPool.signUp(
    '[e-mail]',
    'Password001',

    userAttributes: userAttributes, // ..optional
  );
} catch (e) {
  print(e);
}

Use case 2. Confirming a registered, unauthenticated user using a confirmation code received via SMS/email.

import 'package:amazon_cognito_identity_dart/cognito.dart';

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx');

final cognitoUser = new CognitoUser(
    '[e-mail]', userPool);

var result;
try {
  result = await cognitoUser.confirmRegistration('123456');
} catch (e) {
  print(e);
}
print(result);

Use case 3. Resending a confirmation code via SMS/email for confirming registration for unauthenticated users.

import 'package:amazon_cognito_identity_dart/cognito.dart';

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx');
final cognitoUser = new CognitoUser(
    '[e-mail]', userPool);
final String status;
try {
  status = await cognitoUser.resendConfirmationCode();
} catch (e) {
  print(e);
}

Use case 4. Authenticating a user and establishing a user session with the Amazon Cognito Identity service.

import 'package:amazon_cognito_identity_dart/cognito.dart';

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx');
final cognitoUser = new CognitoUser(
    '[e-mail]', userPool);
final authDetails = new AuthenticationDetails(
    username: '[e-mail]', password: 'Password001');
CognitoUserSession session;
try {
  session = await cognitoUser.authenticateUser(authDetails);
} on CognitoUserNewPasswordRequiredException catch (e) {
  // handle New Password challenge
} on CognitoUserMfaRequiredException catch (e) {
  // handle SMS_MFA challenge
} on CognitoUserSelectMfaTypeException catch (e) {
  // handle SELECT_MFA_TYPE challenge
} on CognitoUserMfaSetupException catch (e) {
  // handle MFA_SETUP challenge
} on CognitoUserTotpRequiredException catch (e) {
  // handle SOFTWARE_TOKEN_MFA challenge
} on CognitoUserCustomChallengeException catch (e) {
  // handle CUSTOM_CHALLENGE challenge
} on CognitoUserConfirmationNecessaryException catch (e) {
  // handle User Confirmation Necessary
} catch (e) {
  print(e);
}
print(session.getAccessToken().getJwtToken());

Use case 5. Retrieve user attributes for authenticated users.

List<CognitoUserAttribute> attributes;
try {
  attributes = await cognitoUser.getUserAttributes();
} catch (e) {
  print(e);
}
attributes.forEach((attribute) {
  print('attribute ${attribute.getName()} has value ${attribute.getValue()}');
});

Use case 7. Delete user attributes for authenticated users.

try {
  final List<String> attributeList = ['nickname'];
  cognitoUser.deleteAttributes(attributeList);
} catch (e) {
  print(e);
}

Use case 8. Update user attributes for authenticated users.

final List<CognitoUserAttribute> attributes = [];
attributes.add(new CognitoUserAttribute(name: 'nickname', value: 'joe'));

try {
  await user.updateAttributes(attributes);
} catch (e) {
  print(e);
}

Use case 14. Signing out from the application.

await cognitoUser.signOut();

Use case 15. Global signout for authenticated users (invalidates all issued tokens).

await cognitoUser.globalSignOut();

Addtional Features

Get AWS Credentials

Get a authenticated user's AWS Credentials. Use with other signing processes like Signature Version 4.

import 'package:amazon_cognito_identity_dart/cognito.dart';

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx');
final cognitoUser = new CognitoUser(
    '[e-mail]', userPool);
final authDetails = new AuthenticationDetails(
    username: '[e-mail]', password: 'Password001'
);
final session = await cognitoUser.authenticateUser(authDetails);

final credentials = new CognitoCredentials(
    'ap-southeast-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx', userPool);
await credentials.getAwsCredentials(session.getIdToken().getJwtToken());
print(credentials.accessKeyId);
print(credentials.secretAccessKey);
print(credentials.sessionToken);

Signing Requests

Signing requests for authenticated users for access to secured routes to API Gateway and Lambda.

import 'package:http/http.dart' as http;
import 'package:amazon_cognito_identity_dart/cognito.dart';
import 'package:amazon_cognito_identity_dart/sig_v4.dart';

final credentials = new CognitoCredentials(
    'ap-southeast-1:xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx', userPool);
await credentials.getAwsCredentials(session.getIdToken().getJwtToken());

const endpoint =
    'https://xxxx.execute-api.ap-southeast-1.amazonaws.com/dev';
final awsSigV4Client = new AwsSigV4Client(credentials.accessKeyId,
    credentials.secretAccessKey, endpoint,
    sessionToken: credentials.sessionToken, region: 'ap-southeast-1');

final signedRequest = new SigV4Request(awsSigV4Client,
    method: 'POST',
    path: '/projects',
    headers: new Map<String, String>.from(
        {'header-1': 'one', 'header-2': 'two'}),
    queryParams: new Map<String, String>.from({'tracking': 'x123'}),
    body: new Map<String, dynamic>.from({'color': 'blue'}));

http.Response response;
try {
  response = await http.post(
      signedRequest.url,
      headers: signedRequest.headers, body: signedRequest.body);
} catch (e) {
  print(e);
}
print(response.body);

Use Custom Storage

Persist user session using custom storage.

import 'dart:convert';
import 'package:amazon_cognito_identity_dart/cognito.dart';

Map<String, String> _storage = {};

class CustomStorage extends CognitoStorage {
  String prefix;
  CustomStorage(this.prefix);
  // Write do storage file/DB
  setItem(String key, value) async {
    _storage[prefix+key] = json.encode(value);
    return _storage[prefix+key];
  }
  // Read from storage file/DB
  getItem(String key) async {
    if (_storage[prefix+key] != null) {
      return json.decode(_storage[prefix+key]);
    }
    return null;
  }
  // Remove from storage file/DB
  removeItem(String key) async {
    return _storage.remove(prefix+key);
  }
  // Clear completely
  clear() async {
    _storage = {};
  }
}

final customStore = new CustomStorage('custom:');

final userPool = new CognitoUserPool(
    'ap-southeast-1_xxxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxx',
    storage: customStore);
final cognitoUser = new CognitoUser(
    '[e-mail]', userPool,
    storage: customStore);
final authDetails = new AuthenticationDetails(
    username: '[e-mail]', password: 'Password001');
await cognitoUser.authenticateUser(authDetails);

// some time later...
final user = await userPool.getCurrentUser();
final session = await user.getSession();
print(session.isValid());