Ably Flutter Plugin
Ably is the platform that powers synchronized digital experiences in realtime. Whether attending an event in a virtual venue, receiving realtime financial information, or monitoring live car performance data – consumers simply expect realtime digital experiences as standard. Ably provides a suite of APIs to build, extend, and deliver powerful digital experiences in realtime for more than 250 million devices across 80 countries each month. Organizations like Bloomberg, HubSpot, Verizon, and Hopin depend on Ably’s platform to offload the growing complexity of business-critical realtime data synchronization at global scale. For more information, see the Ably documentation.
Supported platforms
- Android
- iOS
- Push notifications, check support section
Requirements
- Flutter 2.5.0 or higher
- iOS 10 or newer
- Android API Level 19 (Android 4.4, KitKat) or newer
This project uses Java 8 language features, utilizing Desugaring to support lower versions of the Android runtime (i.e. API Levels prior to 24).
If your project needs support for SDK Version lower than 24, Android Gradle Plugin 4.0.0+ must be used. You might also need to upgrade gradle distribution accordingly.
Installation
Specify Dependency
In pubspec.yaml
file:
dependencies:
ably_flutter: ^1.2.35
Import the package
import 'package:ably_flutter/ably_flutter.dart' as ably;
Updating to a newer version
When increasing the version of ably_flutter
in your pubspec.yaml
, if there are breaking changes, follow the updating / migration guide.
Usage
Please check demo code snippets and flutter example app for more detailed usage.
Authentication
Authentication using API Key
// Create an instance of ClientOptions with Ably key
final clientOptions = ably.ClientOptions(key: '<KEY>');
// Use ClientOptions to create Realtime or REST instance
ably.Realtime realtime = ably.Realtime(options: clientOptions);
ably.Rest rest = ably.Rest(options: clientOptions);
Also see docs: Auth and Security: Basic authentication
Token Authentication
Supplying a TokenCallback
:
// Create an instance of ClientOptions with Ably token and authCallback
ably.ClientOptions clientOptions = ably.ClientOptions(
key: '<TOKEN>',
clientId: '<CLIENT>', // Optional
authCallback: (ably.TokenParams tokenParams) async {
// `createTokenRequest` should be implemented to communicate with user server
ably.TokenRequest tokenRequest = await createTokenRequest(tokenParams);
// `authCallback` has to return an instance of TokenRequest
return tokenRequest;
}
);
// Use ClientOptions to create Realtime or REST instance
ably.Realtime realtime = ably.Realtime(options: clientOptions);
ably.Rest rest = ably.Rest(options: clientOptions);
Also see docs: Auth and Security: Token authentication
Realtime instance
Create an instance of the Realtime Client
ably.Realtime realtime = ably.Realtime(options: clientOptions);
Read Realtime time
DateTime time = realtime.time()
Connection state
Listen for all connection state events
realtime.connection
.on()
.listen((ably.ConnectionStateChange stateChange) async {
// Handle connection state change events
});
Listen for particular connection state event
realtime.connection
.on(ably.ConnectionEvent.connected) // Any type of `ConnectionEvent` can be specified
.listen((ably.ConnectionStateChange stateChange) async {
// Handle connection state change events
});
Retrieve connection id, state etc
String connectionId = realtime.connection.id;
ConnectionState state = realtime.connection.state;
String recoveryKey = await realtime.connection.createRecoveryKey(); // https://ably.com/docs/connect/states?q=recovery#connection-state-recover-options
Realtime channel
Create instance of Realtime channel
ably.RealtimeChannel channel = realtime.channels.get('channel-name');
Attach and detach from channel
await channel.attach()
await channel.detach()
Channel state
Listen for all channel state events
channel
.on()
.listen((ably.ChannelStateChange stateChange) async {
// Handle channel state change events
});
Listen for particular channel state event
channel
.on(ably.ChannelEvent.failed) // Any type of `ConnectionEvent` can be specified
.listen((ably.ChannelStateChange stateChange) async {
// Handle channel state change events
});
Channel messages
Listen for all messages
StreamSubscription<ably.Message> subscription =
channel
.subscribe()
.listen((ably.Message message) {
// Handle channel message
});
Listen for message with selected name
StreamSubscription<ably.Message> subscription =
channel
.subscribe(name: 'event1')
.listen((ably.Message message) {
// Handle channel messages with name 'event1'
});
Listen for messages with a set of selected names
StreamSubscription<ably.Message> subscription =
channel
.subscribe(names: ['event1', 'event2'])
.listen((ably.Message message) {
// Handle channel messages with name 'event1' or `event2`
});
Stop listening for messages
await subscription.cancel()
Publish single message on channel
// Publish simple message
await channel.publish(
name: "event1",
data: "hello world",
);
// Publish message data as json-encodable object
await channel.publish(
name: "event1",
data: {
"hello": "world",
"hey": "ably",
},
);
// Publish message as array of json-encodable objects
await channel.publish(
name: "event1",
data: [
{
"hello": {
"world": true,
},
"ably": {
"serious": "realtime",
},
],
);
// Publish message as an `ably.Message` object
await channel.publish(
message: ably.Message(
name: "event1",
data: {
"hello": "world",
}
),
);
Publish multiple messages on channel
await channel.publish(
messages: [
ably.Message(
name: "event1",
data: {
"hello": "world",
}
),
ably.Message(
name: "event1",
data: {
"hello": "ably",
}
),
],
);
Channel history
Read channel history
// Get channel history with default parameters
ably.PaginatedResult<ably.Message> history = await channel.history()
// Get channel history with custom parameters
ably.PaginatedResult<ably.Message> filteredHistory = await channel.history(
ably.RealtimeHistoryParams(
direction: 'forwards',
limit: 10,
)
)
Realtime presence
Enter Realtime presence
// Enter using client ID from `ClientOptions`
await channel.presence.enter();
// Enter using client ID from `ClientOptions` with additional data
await channel.presence.enter("hello");
await channel.presence.enter([1, 2, 3]);
await channel.presence.enter({"key": "value"});
// Enter with specified client ID
await channel.presence.enterClient("user1");
// Enter with specified client ID and additional data
await channel.presence.enterClient("user1", "hello");
await channel.presence.enterClient("user1", [1, 2, 3]);
await channel.presence.enterClient("user1", {"key": "value"});
Update Realtime presence
// Update using client ID from `ClientOptions`
await channel.presence.update();
// Update using client ID from `ClientOptions` with additional data
await channel.presence.update("hello");
await channel.presence.update([1, 2, 3]);
await channel.presence.update({"key": "value"});
// Update with specified client ID
await channel.presence.updateClient("user1");
// Update with specified client ID and additional data
await channel.presence.updateClient("user1", "hello");
await channel.presence.updateClient("user1", [1, 2, 3]);
await channel.presence.updateClient("user1", {"key": "value"});
Leave Realtime presence
// Leave using client ID from `ClientOptions`
await channel.presence.leave();
// Leave using client ID from `ClientOptions` with additional data
await channel.presence.leave("hello");
await channel.presence.leave([1, 2, 3]);
await channel.presence.leave({"key": "value"});
// Leave with specified client ID
await channel.presence.leaveClient("user1");
// Leave with specified client ID and additional data
await channel.presence.leaveClient("user1", "hello");
await channel.presence.leaveClient("user1", [1, 2, 3]);
await channel.presence.leaveClient("user1", {"key": "value"});
Get Realtime presence
// Get all presence messages
List<ably.PresenceMessage> presenceMessages = await channel.presence.get();
// Get presence messages with specific Client ID
presenceMessages = await channel.presence.get(
ably.RealtimePresenceParams(
clientId: 'clientId',
),
);
// Get presence messages with specific Connection ID
presenceMessages = await channel.presence.get(
ably.RealtimePresenceParams(
connectionId: 'connectionId',
),
);
Read Realtime presence history
// Get presence history with default parameters
ably.PaginatedResult<ably.PresenceMessage> history = await channel.presence.history()
// Get presence history with custom parameters
ably.PaginatedResult<ably.PresenceMessage> filteredHistory = await channel.presence.history(
ably.RealtimeHistoryParams(
direction: 'forwards',
limit: 10,
)
)
Listen for all Realtime presence messages
StreamSubscription<ably.PresenceMessage> subscription =
channel
.presence
.subscribe()
.listen((presenceMessage) {
// Handle presence message
},
);
Listen for a particular presence message
StreamSubscription<ably.PresenceMessage> subscription =
channel
.presence
.subscribe(action: PresenceAction.enter)
.listen((presenceMessage) {
// Handle `enter` presence message
},
);
Listen for a set of particular presence messages
StreamSubscription<ably.PresenceMessage> subscription =
channel
.presence
.subscribe(actions: [
PresenceAction.enter,
PresenceAction.update,
])
.listen((presenceMessage) {
// Handle `enter` and `update` presence message
},
);
REST instance
Create an instance of the REST Client
ably.Rest rest = ably.Rest(options: clientOptions);
Read REST time
DateTime time = rest.time()
REST channel
Create instance of REST channel
ably.RestChannel channel = rest.channels.get('channel-name');
REST channel messages
Publish single message on REST channel
// Publish simple message
await channel.publish(
name: "event1",
data: "hello world",
);
// Publish message data as json-encodable object
await channel.publish(
name: "event1",
data: {
"hello": "world",
"hey": "ably",
},
);
// Publish message as array of json-encodable objects
await channel.publish(
name: "event1",
data: [
{
"hello": {
"world": true,
},
"ably": {
"serious": "realtime",
},
],
);
// Publish message as an `ably.Message` object
await channel.publish(
message: ably.Message(
name: "event1",
data: {
"hello": "world",
}
),
);
Publish multiple messages on REST channel
await channel.publish(
messages: [
ably.Message(
name: "event1",
data: {
"hello": "world",
}
),
ably.Message(
name: "event1",
data: {
"hello": "ably",
}
),
],
);
REST channel history
Read REST channel history
// Get channel history with default parameters
ably.PaginatedResult<ably.Message> history = await channel.history()
// Get channel history with custom parameters
ably.PaginatedResult<ably.Message> filteredHistory = await channel.history(
ably.RestHistoryParams(
direction: 'forwards',
limit: 10,
)
)
REST presence
Get REST presence
// Get all presence messages
List<ably.PresenceMessage> presenceMessages = await channel.presence.get();
// Get presence messages with specific Client ID
presenceMessages = await channel.presence.get(
ably.RestPresenceParams(
clientId: 'clientId',
),
);
// Get presence messages with specific Connection ID
presenceMessages = await channel.presence.get(
ably.RestPresenceParams(
connectionId: 'connectionId',
),
);
Read REST presence history
// Get presence history with default parameters
ably.PaginatedResult<ably.PresenceMessage> history = await channel.presence.history();
// Get presence history with custom parameters
ably.PaginatedResult<ably.PresenceMessage> filteredHistory = await channel.presence.history(
ably.RestHistoryParams(
direction: 'forwards',
limit: 10,
)
);
PaginatedResult handling
Get items on current page
// Example PaginatedResult returned from channel history
ably.PaginatedResult<ably.Message> paginatedResult = await channel.history(params);
// Get list of items from result
List<ably.Message> items = paginatedResult.items;
Get next page if available
// Example PaginatedResult returned from channel history
ably.PaginatedResult<ably.Message> paginatedResult = await channel.history(params);
// Check if next page is available
bool hasNextPage = paginatedResult.hasNext();
// Fetch next page if it's available
if (hasNextPage) {
paginatedResult = await paginatedResult.next();
}
Encryption
Create CipherParams
String key = 'base64EncodedKey'; // Can also be an UInt8List
CipherParams cipherParams = ably.Crypto.getDefaultParams(key: key);
Setup encryption on a channel
// For Realtime
RealtimeChannelOptions realtimeChannelOptions = ably.RealtimeChannelOptions(cipherParams: cipherParams);
RealtimeChannel channel = realtime.channels.get("channel-name");
channel.setOptions(realtimeChannelOptions)
// For REST
RestChannelOptions restChannelOptions = ably.RestChannelOptions(cipherParams: cipherParams);
RestChannel channel = rest.channels.get("channel-name");
channel.setOptions(restChannelOptions)
Known limitations
Missing features
Features that we do not currently support, but we do plan to add in the future:
RTE6a compliance
Using the Streams based approach doesn't fully conform with RTE6a from our client library features specification.
StreamSubscription subscriptionToBeCancelled;
// Listener registered 1st
realtime.connection.on().listen((ably.ConnectionStateChange stateChange) async {
if (stateChange.event == ably.ConnectionEvent.connected) {
await subscriptionToBeCancelled.cancel(); // Cancelling 2nd listener
}
});
// Listener registered 2nd
subscriptionToBeCancelled = realtime.connection.on().listen((ably.ConnectionStateChange stateChange) async {
print('State changed');
});
In the example above, the 2nd listener is cancelled when the 1st listener is notified about the "connected" event. As per RTE6a, the 2nd listener should also be triggered. It will not be as the 2nd listener was registered after the 1st listener and stream subscription is cancelled immediately after 1st listener is triggered.
This wouldn't have happened if the 2nd listener had been registered before the 1st was.
The Workaround - Cancelling using delay
Instead of await subscriptionToBeCancelled.cancel();
, use
Future<void>.delayed(Duration.zero, () {
subscriptionToBeCancelled.cancel();
});
Push Notifications
By default, push-related components in the sample app won't work on Android, because of a dummy google-services.json file. In order to use push messaging features of Ably SDK, additional FCM/APNS configuration is required.
See PushNotifications.md for detailed information on getting PN working with the example app.
Feature support
See Ably feature support matrix for a list of features supported by this SDK.
Support, feedback and troubleshooting
Please visit ably.com/support for access to our knowledge base and to ask for any assistance.
To see what has changed in recent versions, see the CHANGELOG.
Contributing
For guidance on how to contribute to this project, see CONTRIBUTING.md.