Configuration API for Dart SDK

Dart complete API reference for building Realtime Applications on PubNub, including basic usage and sample code.

Configuration

Dart SDK allows you to create various configurations for different subscribe keys. Each configuration is stored in a Keyset object.

You can use a KeysetStore to store your Keysets but make sure that individual Keyset names are unique and note that only one can be the default.

Method(s)

Keyset(
  {String subscribeKey,
  String publishKey,
  String secretKey,
  String authKey,
  UserId userId}
) 

The Keyset object has the following properties:

* required

Parameter	Description
`subscribeKey` * Type: `String` Default: n/a	`subscribeKey` from the Admin Portal.
`publishKey` Type: `String` Default: n/a	`publishKey` from the Admin Portal (only required if publishing).
`secretKey` Type: `String` Default: n/a	`secretKey` used for administrative tasks.
`authKey` Type: `String` Default: n/a	If Access Manager is enabled, all communications to and from PubNub are encrypted.
`userId` * Type: `String` Default: n/a	`userId` to use. You should set a unique identifier for the user or the device that connects to PubNub. It's a UTF-8 encoded string of up to 92 alphanumeric characters. If you don't set the `userId`, you won't be able to connect to PubNub.
~~`cipherKey`~~ Type: ~~`String`~~ Default: n/a	This way of setting this parameter is deprecated, pass it to `crypto` instead. ~~If passed, all communications to and from PubNub will be encrypted.~~
~~`UUID`~~ * Type: ~~`String`~~ Default: n/a	This parameter is deprecated, use `userId` instead. `UUID` to use. You should set a unique `UUID` to identify the user or the device that connects to PubNub. If you don't set the `UUID`, you won't be able to connect to PubNub.

Basic Usage

Reference code

This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

Required UserId

Always set the userId to uniquely identify the user or device that connects to PubNub. This userId should be persisted, and should remain unchanged for the lifetime of the user or the device. If you don't set the userId, you won't be able to connect to PubNub.

import 'package:pubnub/pubnub.dart';

void main() {
  // Configure the Keyset with required parameters
  final myKeyset = Keyset(
    subscribeKey: 'demo', 
    publishKey: 'demo', 
    userId: UserId('myUniqueUserId')
  );

  print('Keyset configured with subscribeKey: ${myKeyset.subscribeKey}');
}

Initialization

Add PubNub to your project using one of the procedures defined in Getting Started.

Description

To use the Dart SDK, instantiate the PubNub class with a default Keyset. The default Keyset is used any time a specific Keyset isn't explicitly passed into a method. All methods that you call try to obtain the keyset according to these rules:

The keyset parameter has the highest priority.
If keyset is null, the method tries to get a keyset from the using parameter.
If using is null, the method tries to get the default keyset.
If the default keyset isn't defined, the method throws an error.

Methods

To initialize PubNub, you can use the following constructor in the Dart SDK:

PubNub(
  {Keyset defaultKeyset, 
  INetworkingModule networking,
  IParserModule parser, 
  ICryptoModule crypto}
) 

The PubNub constructor takes the following arguments:

* required

Parameter	Description
`defaultKeyset` * Type: `Keyset` Default: n/a	The default keyset to use.
`networking` Type: `INetworkingModule` Default: `NetworkingModule`	The default networking module to use. Inside this module, you can configure a custom origin and whether to use SSL.
`parser` Type: `IParserModule` Default: `ParserModule`	The default parser module to use for parsing data.
`crypto` Type: `ICryptoModule` Default: `CryptoModule`	The cryptography module used for encryption and decryption of messages and files. Takes the `cipherKey` parameter as argument. For more information, refer to the cryptoModule section.

`cryptoModule`

cryptoModule provides encrypt/decrypt functionality for messages and files. From the 4.2.4 release on, you can configure how the actual encryption/decryption algorithms work.

Each PubNub SDK is bundled with two ways of encryption: the legacy encryption with 128-bit cipher key entropy and the recommended 256-bit AES-CBC encryption. For more general information on how encryption works, refer to the Message Encryption and File Encryption sections.

If you do not explicitly set the cryptoModule in your app and have the cipherKey param set in PubNub config, the client defaults to using the legacy encryption.

Legacy encryption with 128-bit cipher key entropy

You don't have to change your encryption configuration if you want to keep using the legacy encryption. If you want to use the recommended 256-bit AES-CBC encryption, you must explicitly set that in PubNub config.

`cryptoModule` configuration

To configure the cryptoModule to encrypt all messages/files, you can use the following methods in the Dart SDK:

// encrypts using 256-bit AES-CBC cipher (recommended)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
var cryptoModule = CryptoModule.aescbcCryptoModule(CipherKey.fromUtf8('enigma'));

// encrypts with 128-bit cipher key entropy (legacy)
// decrypts data encrypted with the legacy and the 256-bit AES-CBC ciphers
var cryptoModule = CryptoModule.legacyCryptoModule(CipherKey.fromUtf8('enigma'));

// partial encryption
// create cryptoModule
var cryptoModule = CryptoModule.aesCbcCryptoModule(CipherKey.fromUtf8('abcd'));

// encrypt normal message
var encrypted = cryptoModule.encrypt('Hello'.codeUnits);

show all 17 lines

Your client can decrypt content encrypted using either of the modules. This way, you can interact with historical messages or messages sent from older clients while encoding new messages using the more secure 256-bit AES-CBC cipher.

Older SDK versions

Apps built using the SDK versions lower than 4.2.4 will not be able to decrypt data encrypted using the 256-bit AES-CBC cipher. Make sure to update your clients or encrypt data using the legacy algorithm.

Basic Usage

import 'package:pubnub/pubnub.dart';

void main() async {
  // Initialize PubNub with the configured Keyset
  final myKeyset = Keyset(
    subscribeKey: 'demo', 
    publishKey: 'demo', 
    userId: UserId('myUniqueUserId')
  );
  
  final pubnub = PubNub(defaultKeyset: myKeyset);

}

Returns

Initialization returns the PubNub instance for invoking PubNub APIs like publish(), subscribe(), etc.

Other Examples

Initialize a non-secure client

final pubnub =
  PubNub(
    defaultKeyset: myKeyset, 
    networking: NetworkingModule(ssl: false));

Initialization for a Read-Only client

final pubnub = PubNub(
  defaultKeyset:
    Keyset(subscribeKey: 'mysubscribeKey',
    userId: UserId('myUniqueUserId')));

Initialization with custom origin

If your use-case requires to route traffic through custom domain instead of the default one, you can set up your SDK such that all your traffic is routed through example.com:

final pubnub = PubNub(
  defaultKeyset: myKeyset,
  networking: NetworkingModule(origin: 'example.com', ssl: true),
);

Initializing with SSL Enabled

This example demonstrates how to enable PubNub Transport Layer Encryption with SSL. Just initialize the client with ssl set to true. The hard work is done, now the PubNub API takes care of the rest. Just subscribe and publish as usual and you are good to go.

final pubnub =
  PubNub(
    defaultKeyset: myKeyset,
    networking: NetworkingModule(ssl: true));

Initializing with Access Manager

Requires Access Manager add-on

This method requires that the Access Manager add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Secure your secretKey

Anyone with the secretKey can grant and revoke permissions to your app. Never let your secretKey be discovered, and to only exchange it / deliver it securely. Only use the secretKey on secure server-side platforms.

When you init with secretKey, you get root permissions for the Access Manager. With this feature you don't have to grant access to your servers to access channel data. The servers get all access on all channels.

For applications that will administer Access Manager permissions, the API is initialized with the secretKey as in the following example:

final pubnub = PubNub(
  defaultKeyset: Keyset(
    subscribeKey: 'mySubscribeKey',
    secretKey: 'my_secretkey',
    userId: UserId('myUniqueUserId')));

Now that the pubnub object is instantiated the client will be able to access the Access Manager functions. The pubnub object will use the secretKey to sign all Access Manager messages to the PubNub Network.

Event Listeners

You can be notified of connectivity status, message, and presence notifications via the listeners. For the listeners to work, you must have a Subscription. For more information, refer to the Subscription section.

Listeners

The following listeners are available:

message
signal
objects
messageAction
file

subscription.messages.listen((envelope) {
    switch (envelope.messageType) {
      case MessageType.normal:
          print('${envelope.publishedBy} sent a message: ${envelope.content}');
          print('${envelope.channel}'); //to display the channel that message was sent on
          print('${envelope.publishedAt}'); // to display timetoken of the message received
          print('${envelope.content}'); // to display content of the message
          print('${envelope.uuid}'); // to display the uuid of the sender
          break;
      case MessageType.signal:
          print('${envelope.publishedBy} sent a signal message: ${envelope.content}');
          print('${envelope.channel}'); //to display the channel that message was sent on
          print('${envelope.publishedAt}'); // to display timetoken of the message received
          print('${envelope.content}'); // to display content of the message
          print('${envelope.uuid}'); // to display the uuid of the sender
show all 55 lines

userID

These functions are used to set/get a user ID on the fly.

Methods

To set/get userId you can use the following method(s) in the Dart SDK:

var myKeyset =
  Keyset(subscribeKey: 'subscribeKey', userId: UserId('myUniqueUserId'));

* required

Parameter	Description
`userId` * Type: `String` Default: n/a	User ID to be used as a device identifier.

Basic Usage

Required UserId

final pubnub = PubNub(
    defaultKeyset: Keyset(
        subscribeKey: 'mySubscribeKey',
        userId: UserId('myUniqueUserId')));

// to know which userId is set
var userId = pubnub.keysets.defaultKeyset.userId;

Authentication Key

Setter and getter for users' authentication key.

Method(s)

var myKeyset = Keyset(
  subscribeKey: 'subscribeKey',
  authKey: 'myAuthkey',
  userId: UserId('myUniqueUserId'));

* required

Parameter	Description
`authKey` * Type: `String`	If Access Manager is utilized, client will use this `authKey` in all restricted requests.

Basic Usage

final pubnub = PubNub(
  defaultKeyset: Keyset(
    subscribeKey: 'mySubscribeKey',
    authKey: 'myAuthkey',
    userId: UserId('myUniqueUserId')));

Filter Expression

Requires Stream Controller add-on

This method requires that the Stream Controller add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Stream filtering allows a subscriber to apply a filter to only receive messages that satisfy the conditions of the filter. The message filter is set by the subscribing client(s) but it's applied on the server side thus preventing unwanted messages (those that do not meet the conditions of the filter) from reaching the subscriber.

To set or get message filters, you can use the following method. To learn more about filtering, refer to the Publish Messages documentation.

Method(s)

// to know which filter expression is set
var filterExpression = pubnub.keysets.defaultKeyset.filterExpression;

* required

Parameter	Description
`filterExpression` * Type: `String`	PSV2 feature to `subscribe` with a custom filter expression.

Basic Usage

var myKeyset =
    Keyset(subscribeKey: 'subscribeKey', userId: UserId('myUniqueUserId'))
    ..filterExpression = 'such=wow';

final pubnub = PubNub(defaultKeyset: myKeyset);

Handling Disconnects

The client may disconnect due to unpredictable network conditions. By default, the client reconnects exponentially for subscribe connections only.

For more information, refer to SDK connection lifecycle.

You can configure automatic reconnection as follows:

var pubnub = PubNub(
    networking:
        NetworkingModule(retryPolicy: RetryPolicy.exponential(maxRetries: 10)));

Available retry policies include:

RetryPolicy.exponential({int? maxRetries, int? maximumDelay});
RetryPolicy.linear({int? backoff, int? maxRetries, int? maximumDelay})

Argument	Type	Description
`maximumDelay`	`int`	Maximum amount of milliseconds to wait until retry is executed.
`backoff`	`int`	Backoff amount in milliseconds.
`maxRetries`	`int`	Number of max retries.

Configuration​

Method(s)​

Basic Usage​

Reference code

Required UserId

Initialization​

Description​

Methods​

cryptoModule​

Legacy encryption with 128-bit cipher key entropy

cryptoModule configuration​

Older SDK versions

Basic Usage​

Returns​

Other Examples​

Initialize a non-secure client​

Initialization for a Read-Only client​

Initialization with custom origin​

Initializing with SSL Enabled​

Initializing with Access Manager​

Requires Access Manager add-on

Secure your secretKey

Event Listeners​

Listeners​

userID​

Methods​

Basic Usage​

Required UserId

Authentication Key​

Method(s)​

Basic Usage​

Filter Expression​

Requires Stream Controller add-on

Method(s)​

Basic Usage​

Handling Disconnects​

Configuration

Method(s)

Basic Usage

Initialization

Description

Methods

`cryptoModule`

`cryptoModule` configuration

Basic Usage

Returns

Other Examples

Initialize a non-secure client

Initialization for a Read-Only client

Initialization with custom origin

Initializing with SSL Enabled

Initializing with Access Manager

Event Listeners

Listeners

userID

Methods

Basic Usage

Authentication Key

Method(s)

Basic Usage

Filter Expression

Method(s)

Basic Usage

Handling Disconnects