Presence API for Dart SDK

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

Presence lets you track who is online or offline and store custom state information. Presence shows:

• When a user has joined or left a channel
• How many users are subscribed to a particular channel (occupancy)
• Which channels a user or device is subscribed to
• Presence state associated with these users

Learn more about our Presence feature in the Presence overview.

Here now

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

This method returns information about the current state of a channel, including a list of unique user IDs (universally unique identifiers, UUIDs) currently subscribed to the channel and the total occupancy count of the channel.

Cache

This method has a 3-second response cache time.

Method(s)

To call Here Now you can use the following methods in the Dart SDK:

1pubnub.hereNow(
2  {Keyset? keyset,
3  String? using,
4  Set<String> channels = const {},
5  Set<String> channelGroups = const {},
6  StateInfo? stateInfo}
7) 

* required

Parameter	Description
keyset Type: Keyset Default: n/a	Override for the PubNub default keyset configuration.
using Type: String Default: n/a	Keyset name from the keysetStore to be used for this method call.
channels Type: Set<String> Default: n/a	The channels to get the 'here now' details of.
channelGroups Type: Set<String> Default: n/a	The channelGroups to get the 'here now' details of. Wildcards are not supported.
stateInfo Type: StateInfo Default: false	If true, the response will include the presence states of the users for channels/channelGroups.

Sample code

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.

Get a list of UUIDs subscribed to channel

1import 'package:pubnub/pubnub.dart';
2

3void main() async {
4  // Create PubNub instance with default keyset.
5  var pubnub = PubNub(
6    defaultKeyset: Keyset(
7      subscribeKey: 'demo',
8      publishKey: 'demo',
9      userId: UserId('myUniqueUserId'),
10    ),
11  );
12

13  // Channel to get presence information
14  String channel = 'my_channel';
15

16  try {
17    // Get presence information
18    var result = await pubnub.hereNow(channels: {channel});
19

20    // Print the total occupancy and UUIDs
21    print('Total Occupancy: ${result.totalOccupancy}');
22    result.channels[channel]?.uuids.forEach((uuid, info) {
23      print('UUID: $uuid, State: ${info.state}');
24    });
25  } catch (e) {
26    print('Error retrieving presence information: $e');
27  }
28}

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Returns

The hereNow() operation returns a HereNowResult which contains the following operations:

Property Name	Type	Description
totalChannels	int	Total channels.
totalOccupancy	int	Total occupancy.
channels	Map<String?, ChannelOccupancy>	A map with values of ChannelOccupancy for each channel. See ChannelOccupancy for more details.

ChannelOccupancy

Property Name	Type	Description
channelName	String	Channel name.
count	int	Occupancy of the channel.
uuids	Map<String, OccupantInfo>	A map of OccupantInfo, see OccupantInfo for more details.

OccupantInfo

Property Name	Type	Description
uuid	String	UUID of the user.
state	dynamic	State of the user.

Other examples

Returning state

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

1var result =
2    await pubnub.hereNow(channels: {'my_channel'}, stateInfo: StateInfo.all);

Example response:

1{
2    "status" : 200,
3    "message" : "OK",
4    "service" : "Presence",
5    "uuids" : [
6        {
7            "uuid" : "myUUID0"
8        },
9        {
10            "state" : {
11                "abcd" : {
12                    "age" : 15
13                }
14            },
15            "uuid" : "myUUID1"
16        },
17        {
18            "uuid" : "b9eb408c-bcec-uuid-b4c4-fabec057ad0d"
19        },
20        {
21            "state" : {
22                "abcd" : {
23                    "age" : 15
24                }
25            },
26            "uuid" : "myUUID2"
27        },
28        {
29            "state" : {
30                "abcd" : {
31                    "age" : 24
32                }
33            },
34            "uuid" : "myUUID9"
35        }
36    ],
37    "occupancy" : 5
38}

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Return occupancy only

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

To return only occupancy for a channel, set the relevant flags to exclude UUIDs and state.

1var result =
2    await pubnub.hereNow(channels: {'my_channel'});

Example response:

1{
2    "status": 200,
3    "message": "OK",
4    "payload": {
5        "channels": {
6            "81d8d989-b95f-443c-a726-04fac323b331": {
7                "uuids": [ "70fc1140-uuid-4abc-85b2-ff8c17b24d59" ],
8                "occupancy": 1
9            },
10            "81b7a746-d153-49e2-ab70-3037a75cec7e": {
11                "uuids": [ "91363e7f-uuid-49cc-822c-52c2c01e5928" ],
12                "occupancy": 1
13            },
14            "c068d15e-772a-4bcd-aa27-f920b7a4eaa8": {
15                "uuids": [ "ccfac1dd-uuid-4afd-9fd9-db11aeb65395" ],
16                "occupancy": 1
17            }
18        },
19        "total_channels": 3,
20        "total_occupancy": 3
21    },
22    "service": "Presence"
23}

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Here now for channel groups

1var result = await pubnub.hereNow(channelGroups: {'cg1'});

Example response:

1{
2    occupancy : 4,
3    uuids : ['123123234t234f34fuuid', '143r34f34t34fq34quuid', '23f34d3f4rq34r34ruuid', 'w34tcw45t45tcw435uuid']
4}

Announce heartbeat

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

A device linked to the UUID in the keyset can notify channels and channelGroups about its presence.

Method(s)

To call Announce Heartbeat you can use the following methods in the Dart SDK:

1pubnub.announceHeartbeat(
2  {Keyset? keyset,
3  String? using,
4  Set<String> channels = const {},
5  Set<String> channelGroups = const {},
6  int? heartbeat}
7) 

* required

Parameter	Description
keyset Type: Keyset Default: n/a	Override for the PubNub default keyset configuration.
using Type: String Default: n/a	Keyset name from the keysetStore to be used for this method call.
channels Type: Set<String> Default: n/a	The channels to notify.
channelGroups Type: Set<String> Default: n/a	The channelGroups to notify.
heartbeat Type: int Default: n/a	It is used to set the presence timeout period. It overrides the default value of 300 for Presence Timeout.

Sample code

Announce heartbeat to a single channel

1var result = await pubnub.announceHeartbeat(channels: {'my_channel'});

Announce heartbeat to a channel group

1var result = await pubnub.announceHeartbeat(channelGroups: {'cg1'});

Returns

The announceHeartbeat() operation returns a HeartbeatResult object which does not have actionable data.

Announce leave

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

A device linked to the UUID in the keyset can notify channels and channelGroups that it has left (is no longer present).

Method(s)

To call Announce Leave you can use the following methods in the Dart SDK:

1pubnub.announceLeave(
2  {Keyset? keyset,
3  String? using,
4  Set<String> channels = const {},
5  Set<String> channelGroups = const {}}
6) 

* required

Parameter	Description
keyset Type: Keyset	Override for the PubNub default keyset configuration.
using Type: String	Keyset name from the keysetStore to be used for this method call.
channels Type: Set<String>	The channels to notify.
channelGroups Type: Set<String>	The channelGroups to notify.

Sample code

Announce leave to a single channel

1var result = await pubnub.announceLeave(channels: {'my_channel'});

Announce leave to a channel group

1var result = await pubnub.announceLeave(channelGroups: {'cg1'});

Returns

The announceLeave() operation returns a LeaveResult object which has following property.

Property Name	Type	Description
action	String	Action name, for example leave.

User state

Requires Presence

This method requires that the Presence add-on is enabled for your key in the Admin Portal.

For information on how to receive presence events and what those events are, refer to Presence Events.

Clients can set a dynamic custom state (score, game state, location) for their users on one or more channels and store it on a channel as long as the user stays subscribed.

The state is not persisted, and when the client disconnects, the state data is lost. For more information, refer to Presence State.

Method(s)

Set state

To call Set State you can use the following method in the Dart SDK:

1pubnub.setState(
2  dynamic state, {
3  Keyset? keyset,
4  String? using,
5  Set<String> channels = const {},
6  Set<String> channelGroups = const {},
7})

* required

Parameter	Description
state * Type: dynamic Default: n/a	The state as a JSON object to set for the specified channels or channel groups.
keyset Type: Keyset Default: n/a	Override for the PubNub default keyset configuration.
using Type: String Default: n/a	Keyset name from the keysetStore to be used for this method call.
channels Type: Set<String> Default: {}	Set of channels to set the state.
channelGroups Type: Set<String> Default: {}	Set of channelGroups to set the state.

Get state

To call Get State you can use the following method in the Dart SDK:

1pubnub.getState({
2  Keyset? keyset,
3  String? using,
4  Set<String> channels = const {},
5  Set<String> channelGroups = const {}
6})

* required

Parameter	Description
keyset Type: Keyset Default: n/a	Override for the PubNub default keyset configuration.
using Type: String Default: n/a	Keyset name from the keysetStore to be used for this method call.
channels Type: Set<String> Default: {}	Set of channels to fetch the state.
channelGroups Type: Set<String> Default: {}	Set of channelGroups to fetch the state.

Sample code

Set state

1var state = {'is_typing': true};
2

3var result = await pubnub.setState(
4  state,
5  channels: {'my_channel'}
6);

Get state

1var result = await pubnub.getState(
2  channels: {'ch1', 'ch2', 'ch3'},
3  channelGroups: {'cg1', 'cg2'}
4);

Returns

Set state

The setState operation returns a SetUserStateResult object which indicates the success of the operation.

Get state

The getState operation returns a GetUserStateResult object which contains the following operations:

Method	Description
stateByUUID() Type: Map<String, Object>	Map of UUIDs and their associated user states.