Presence API for Rust SDK
Presence enables you to track the online and offline status of users and devices in real time and store custom state information. Presence provides authoritative information on:
- When a user has joined or left a channel
- Who, and how many, users are subscribed to a particular channel
- Which channel(s) an individual user is subscribed to
- Associated state information for these users
Learn more about our Presence feature here.
Here Now
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
You can obtain information about the current state of a channel including a list of unique user IDs currently subscribed to the channel and the total occupancy count of the channel by calling the here_now()
function in your application.
Cache
This method has a 3 second response cache time.
Method(s)
To call here_now()
, use the following method in the Rust SDK:
pubnub
.here_now()
.channels(Vec<String>)
.channel_groups(Vec<String>)
.include_state(bool)
.include_user_ids(bool)
.execute()
Parameter | Description |
---|---|
channels() Type: Vec<String> Default: n/a | The channels to get the details of. |
channel_groups() Type: Vec<String> Default: n/a | The channel groups to get the details of. |
include_state() Type: bool Default: false | If true , the response will include the presence states of the users for channels /channelGroups . |
include_user_ids() Type: bool Default: true | If true, the response will include the user IDs of the connected clients. |
Basic Usage
Get a list of channels, their occupancy, and individual occupants' states
Returns
The here_now()
operation returns a HereNowResult
, which contains the following fields:
Field | Type | Description |
---|---|---|
total_channels | u32 | Total number of channels. |
total_occupancy | u32 | Number of all users in the provided channels. |
channels | Vec<HereNowChannel> | A vector with values of HereNowChannel for each channel. Refer to HereNowChannel for more details. |
HereNowChannel
Field | Type | Description |
---|---|---|
name | String | Channel name. |
occupancy | u32 | Number of all users in the channel. |
occupants | Vec<HereNowUser> | A vector of HereNowUser , refer to HereNowUser for more details. |
HereNowUser
Field | Type | Description |
---|---|---|
user_id | String | Id of the user. |
state | serde_json::Value | State of the user. If you're not using the default serde serialization framework, this field is of type Vec<u8> . |
Where Now
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
You can obtain information about the current list of channels to which a user ID is subscribed to by calling the where_now()
function in your application.
Timeout events
If the app is killed/crashes and restarted (or the page containing the PubNub instance is refreshed on the browser) within the heartbeat window no timeout event is generated.
Method(s)
To call where_now()
, use the following method in the Rust SDK:
pubnub
.where_now()
.user_id(String)
.execute()
Parameter | Description |
---|---|
user_id() Type: String Default: User ID provided in PubNub config | User ID to get the current channel subscriptions for. |
Basic Usage
Returns
The where_now()
operation returns a WhereNowResult
, which contains the following fields:
Field | Type | Description |
---|---|---|
channels | Vec<String> | List of channels where the user ID is present. |
User State
Requires Presence
This method requires that the Presence add-on is enabled for your key in the Admin Portal.
The state API is used to set/get key/value pairs specific to a subscriber user ID.
State information is supplied as a JSON object of key/value pairs.
Presence state format
Presence state must be expressed as a JSON object.
Method(s)
To manage presence state, use any of the following method(s) in the Rust SDK:
Set State
pubnub
.set_presence_state(T: Serialize)
.channels(Vec<String>)
.channel_groups(Vec<String>)
.user_id(String)
.execute()
Parameter | Description |
---|---|
set_presence_state() *Type: T: Serialize Default: n/a | The state to set expressed as a JSON object. |
channels() Type: Vec<String> Default: n/a | Channels to set state on. |
channel_groups() Type: Vec<String> Default: n/a | Channel groups to set state on. |
user_id() Type: String Default: User ID provided in PubNub config | The user ID to set state for. |
Get State
pubnub
.get_presence_state()
.channels(Vec<String>)
.channel_groups(Vec<String>)
.user_id(String)
.execute()
Parameter | Description |
---|---|
channels() Type: Vec<String> Default: n/a | Channels to get state of. |
channel_groups() Type: Vec<String> Default: n/a | Channel groups to set state of. |
user_id() Type: String Default: User ID provided in PubNub config | The user ID to get state for. |
Basic Usage
Returns
The set_presence_state()
operation returns a SetStateResult
which contains the following fields:
Field | Type | Description |
---|---|---|
channel | String | The channel the state was set on. |
state | serde_json::Value | State of the user. If you're not using the default serde serialization framework, this field is of type Vec<u8> . |
The get_presence_state()
operation returns a GetStateResult
which contains the following fields:
Field | Type | Description |
---|---|---|
state | Vec<GetStateInfo> | Vector of GetStateInfo objects. |
GetStateInfo
The GetStateInfo
object contains the following fields:
Field | Type | Description |
---|---|---|
channel_name | String | The channel name the state was set on. |
state | serde_json::Value | State of the user. If you're not using the default serde serialization framework, this field is of type Vec<u8> . |