Configuration API for PubNub Dart SDK

Beta release

This is a beta release. There may be some feature disparity between this and other PubNub SDKs. For more information, visit our blog.

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

Configuration

Description

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, 
  CipherKey cipherKey, 
  UUID uuid}
)

The Keyset object has the following properties:

Properties	Type	Required	Default	Description
`subscribeKey`	`String`	Yes		`subscribeKey` from the Admin Portal.
`publishKey`	`String`	Optional		`publishKey` from the Admin Portal (only required if publishing).
`secretKey`	`String`	Optional		`secretKey` used for administrative tasks.
`cipherKey`	`String`	Optional		If passed, all communications to and from PubNub will be encrypted.
`authKey`	`String`	Optional		If PAM is enabled, all communications to and from PubNub are encrypted.
`UUID`	`String`	Yes	SDK generated UUID	`UUID` to use. You should set a unique `UUID` to identify the user or the device that connects to PubNub. Allowing the SDK to generate a random `UUID` can result in significant billing impacts, particularly on an MAU pricing plan.

Basic Usage

Note

Always set the UUID to uniquely identify the user or device that connects to PubNub. This UUID should be persisted, and should remain unchanged for the lifetime of the user or the device. Not setting the UUID can significantly impact your billing if your account uses the Monthly Active Users (MAUs) based pricing model, and can also lead to unexpected behavior if you have Presence enabled.

final myKeyset = Keyset(
  subscribeKey: 'subscribeKey',
  publishKey: 'publishKey',
  uuid: UUID('yourUniqueUUID'));

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:

Properties	Type	Required	Default	Description
`defaultKeyset`	`Keyset`	Yes		The default keyset to use.
`networking`	`INetworkingModule`	Optional	`NetworkingModule`	The default networking module to use.
`parser`	`IParserModule`	Optional	`ParserModule`	The default parser module to use for parsing data.
`crypto`	`ICryptoModule`	Optional	`CryptoModule`	The default crypto module for data encryption and decryption.

Basic Usage

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',
    uuid: UUID('myUniqueUUID')));

Use a custom UUID

final pubnub = PubNub(
 defaultKeyset:
    Keyset(subscribeKey: 'mySubscribeKey', uuid: UUID('myUniqueUUID')),
);

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-onRequires that the Access Manager add-on is enabled for your key. See this page on enabling add-on features on your keys:
https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-

Note

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 PAM permissions, the API is initialized with the secretKey as in the following example:
```
final pubnub = PubNub(
  defaultKeyset: Keyset(
    subscribeKey: 'mySubscribeKey',
    secretKey: 'my_secretkey',
    uuid: UUID('myUniqueUUID')));
```
Now that the pubnub object is instantiated the client will be able to access the PAM functions. The pubnub object will use the secretKey to sign all PAM messages to the PubNub Network.

UUID

Description

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

Methods

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

var myKeyset =
  Keyset(subscribeKey: 'subscribeKey', uuid: UUID('myUniqueUUID'));

Parameter	Type	Required	Default	Description
`uuid`	`String`	Yes		`UUID` to be used as a device identifier.

Basic Usage

Note

final pubnub = PubNub(
    defaultKeyset: Keyset(
        subscribeKey: 'mySubscribeKey',
        uuid: UUID('myUniqueUUID')));

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

Authentication Key

Description

Setter and getter for users' authentication key.

Method(s)

var myKeyset = Keyset(
  subscribeKey: 'subscribeKey',
  authKey: 'myAuthkey',
  uuid: UUID('myUniqueUUID'));

Parameter	Type	Required	Description
`authKey`	`String`	Yes	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',
    uuid: UUID('myUniqueUUID')));

Filter Expression

Requires Stream Controller add-onRequires that the Stream Controller add-on is enabled for your key. See this page on enabling add-on features on your keys:
https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-

Description

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/get 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;

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

Basic Usage

var myKeyset =
    Keyset(subscribeKey: 'subscribeKey', uuid: UUID('myUniqueUUID'))
    ..filterExpression = 'such=wow';

final pubnub = PubNub(defaultKeyset: myKeyset);

Handling Disconnects

The client may disconnect due to unpredictable network conditions.

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.