Presence | Agora Docs

In Signaling solutions, it is often important to know a user's current online status. For example, in instant messaging, chat applications, and online collaboration tools, users need to see the availability of their contacts. This information is typically displayed as a status message or icon next to a user's name. Presence features in Signaling SDK enable you to monitor join, leave, and status change notifications for users in a channel. Using Presence, you can:

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence provides real-time information about the availability, and the current status of users, for effective communication and collaboration. It enables you to retrieve a list of users in a channel, or to query the list of channels for a specific user. The following figure illustrates how you integrate presence features into your app.

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

To obtain a list of online users in a channel, call getOnlineUsers. Depending on your parameter settings, this method returns a list of online user IDs in a channel and their temporary status data, or just the number of online users in the channel. You do not need to join a channel to call this method. This method is applicable to both message channels and stream channels. Use the channelType parameter to specify the channel type.

After obtaining the initial online users list, update it in real time through presence event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

const options = {
    includedUserId: true,
    includedState: true
};

try {
    const result = await rtm.presence.getOnlineUsers(channelName, channelType, options);
    const { totalOccupancy, occupants, nextPage } = result;
    occupants.forEach((userInfo) => {
        const { states, userId, statesCount } = userInfo;
        console.log(`${userId} has states: ${states}`);
    });
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, ErrorCode: ${errorCode}, due to: ${reason}.`);
}

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the nextPage field in the returned result contains a bookmark for the next page. After each query, check if result.nextPage is not empty to determine if there is more data. To retrieve the next page, set the page field in options to the value of result.nextPage. Repeat this process until result.nextPage is empty. Refer to the following code:

const options = {
    includedUserId: true,
    includedState: true,
    page: "Next_Page_Bookmark"
};
try {
    const result = await rtm.presence.getOnlineUsers(channelName, channelType, options);
    // If nextPage exists, the value of nextPage should be filled into the page field of getOnlineUsers options for the next getOnlineUsers call.
    const { totalOccupancy, occupants, nextPage } = result;
    occupants.forEach((userInfo) => {
        const { states, userId, statesCount } = userInfo;
        console.log(`${userId} has states: ${states}`);
    });
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, ErrorCode: ${errorCode}, due to: ${reason}.`);
}

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includedState and includedUserId in options to false.

const options = {
    includedUserId: false,
    includedState: false,
};
try {
    const result = await rtm.presence.getOnlineUsers(channelName, channelType, options);
    const { totalOccupancy, occupants, nextPage } = getOnlineUsersResult;
    occupants.forEach((userInfo) => {
        const { states, userId, statesCount } = userInfo;
        console.log(`${userId} has states: ${states}`);
    });
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, the error code is ${errorCode}, because of: ${reason}.`);
}

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includedState to true and includedUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

The getUserChannels method enables you to query which channels a user is currently in. This includes the message channels a user has subscribed to and the stream channels they have joined. This method is particularly useful for tracking user paths. Refer to the following sample code:

try {
    const getUserChannelsResult = await rtmClient.presence.getUserChannels(userId);
    const { channels, totalChannel } = getUserChannelsResult;
    channels.forEach((channelInfo) => {
        const { channelName, channelType } = channelInfo;
    });
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, the error code is ${errorCode}, because of: ${reason}.`);
}

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Signaling enables you to set and delete user status messages for the local user in each channel. The SDK notifies other online users in the channel of these changes through event notifications. This feature is useful in use-cases where user status sharing is required, such as real-time synchronization of the user's microphone status, mood, personal signature, score, and message input status.

Signaling does not permanently save the status data. When a user unsubscribes from a channel, times out, or exits a channel, the data is deleted. To save user data permanently, use the Store user metadata feature.

When a user's temporary status changes, Signaling triggers a REMOTE_STATE_CHANGED event notification in real time. Users who set withPresence = true when joining the channel, receive the event notification.

Set status

Using presence, you can set the temporary user status for the local user. When you set the status before subscribing to or joining a channel, the data is cached on the client and does not take effect immediately. The status is updated and corresponding event notifications are triggered when you subscribe to or join a channel. The setState method applies to both message and stream channels; use the channelType parameter to specify the channel type.

const channelName = "test_channel";
const channelType = "MESSAGE";
const states = {
    "Mode": "Happy",
    "Mic": "False",
};
try {
    const result = await rtmClient.presence.setState(channelName, channelType, states);
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, ErrorCode: ${errorCode}, because of: ${reason}.`);
}

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key/value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

const channelName = "Chat_room";
const channelType = "MESSAGE";
const userId = "Tony";
try {
    const result = await rtmClient.presence.getState(userId, channelName, channelType);
    const { states, userId, statesCount } = result; // Tony's temporary state
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, ErrorCode: ${errorCode}, because of: ${reason}.`);
}

Use the getState method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, a RTM_ERROR_PRESENCE_USER_NOT_EXIST error message is returned by the SDK.

Delete status

Each user can set up to 32 key/value pairs in a channel. To remove items that are no longer needed, call removeState with a list of keys. The removeState method only deletes temporary user status data for the local user.

const channelName = "Chat_room";
const channelType = "MESSAGE";
const removeKeys = ["Mode", "Mic"];
const options = {
    states: removeKeys,
}
try {
    const result = await rtmClient.presence.removeState(channelName, channelType, options);
} catch (status) {
    const { operation, reason, errorCode } = status;
    console.log(`${operation} failed, ErrorCode: ${errorCode}, because of: ${reason}.`);
}

Both the setState and removeState methods trigger REMOTE_STATE_CHANGED event notifications. Users who join the channel with withPresence set to true receive event notifications containing full data of the user's temporary status.

Receive presence event notifications

To receive presence event notifications, implement an event listener. See event listeners for details. In addition, set the withPresence parameter to true when subscribing to or joining a channel.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

You set the Max number of instant event value in Agora Console to specify the condition for switching between the two modes. The scheduled notification mode helps prevent event noise that results from a large number of online users in the channel. See Presence configuration for details.

Real-time notification mode

If the number of instant notifications in the channel is less than the Max number of instant event value, presence event notifications operate in real-time notification mode. In this mode, REMOTE_JOIN, REMOTE_LEAVE, REMOTE_TIMEOUT, and REMOTE_STATE_CHANGED notifications are sent to the client in real-time.

{
      eventType: "REMOTE_JOIN";
      channelType: "MESSAGE";
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: {};
      interval: null;
      snapshot: null;
}

{
      eventType: "REMOTE_LEAVE";
      channelType: "MESSAGE";
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: {};
      interval: null;
      snapshot: null;
}

{
      eventType: "REMOTE_TIMEOUT";
      channelType: "MESSAGE";
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: {};
      interval: null;
      snapshot: null;
}

{
      eventType: "SNAPSHOT";
      channelType: "MESSAGE";
      channelName: "test_channel";
      publisher: "";
      stateChanged: {};
      interval: null;
      snapshot: [
          { userId: "user_a", states: {}, statesCount: 0 },
          { userId: "user_b", states: { key_1: "value_1" }, statesCount: 1 },
          { userId: "yourSelf", states: {}, statesCount: 0 },
      ];
}

{
      eventType: "REMOTE_STATE_CHANGED";
      channelType: "MESSAGE";
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: {
          "key_1": "value_1",
      };
      interval: null;
      snapshot: null;
}

Scheduled notification mode

When the number of online users in the channel exceeds the Max number of instant event value, the channel switches to the scheduled notification mode. In this mode, REMOTE_JOIN, REMOTE_LEAVE, REMOTE_TIMEOUT, and REMOTE_STATE_CHANGED events are replaced by INTERVAL events and sent to all users in the channel at specific time intervals. Users receive the following notification:

interval: {
    join: { users: ["Tony", "Lily"], userCount: 2 },
    leave: { users: ["Jason"], userCount: 1 },
    timeout: { users: ["Wang"], userCount: 1 },
    userStateList: [
        {
            userId: "Harvard",
            states: { "Mic": "False", "Position": "Beijing" },
            statesCount: 2,
        },
    ],
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through onPresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

// Set the channelType to MESSAGE or STREAM
RtmChannelType channelType = RtmChannelType.MESSAGE;
PresenceOptions options = new PresenceOptions();
options.setIncludeUserId(true);
options.setIncludeState(true);

mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, new ResultCallback<GetOnlineUsersResult>() {
    @Override
    public void onSuccess(GetOnlineUsersResult result) {
        log(CALLBACK, "getOnlineUsers success");
        for (UserState state : result.getUserStateList()) {
            log(INFO, "user id: " + state.getUserId());
            state.getStates().forEach((key, value) -> {
                log(INFO, "key: " + key + ", value: " + value);
            });
        }
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

// Set the channelType to MESSAGE or STREAM
val channelType = RtmChannelType.MESSAGE
val options = PresenceOptions().apply {
    setIncludeUserId(true)
    setIncludeState(true)
}

mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, object : ResultCallback<GetOnlineUsersResult> {
    override fun onSuccess(result: GetOnlineUsersResult) {
        log(CALLBACK, "getOnlineUsers success")
        for (state in result.userStateList) {
            log(INFO, "user id: " + state.userId)
            state.states.forEach { (key, value) ->
                log(INFO, "key: $key, value: $value")
            }
        }
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the nextPage field in the returned result contains a bookmark for the next page. After each query, check if result.getNextPage is empty to determine if there is more data. To retrieve the next page, set the page field in PresenceOptions to the value of result.getNextPage. Repeat this process until result.getNextPage is null. Refer to the following code:

PresenceOptions options =  new PresenceOptions();
options.setIncludeUserId(true);
options.setIncludeState(true);
options.setPage("your_Next_Page_Bookmark");

// Set the channelType to MESSAGE or STREAM
RtmChannelType channelType = RtmChannelType.MESSAGE;
mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, new ResultCallback<GetOnlineUsersResult>() {
    @Override
    public void onSuccess(GetOnlineUsersResult result) {
        // If nextPage exists, fill the value of nextPage into the page field of getOnlineUsersOptions for the next getOnlineUsers call
        log(CALLBACK, "getOnlineUsers success");
        log(INFO, "next page: " + result.getNextPage());
        for (UserState state : result.getUserStateList()) {
            log(INFO, "user id: " + state.getUserId());
            state.getStates().forEach((key, value) -> {
                log(INFO, "key: " + key + ", value: " + value);
            });
        }
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

val options = PresenceOptions().apply {
    setIncludeUserId(true)
    setIncludeState(true)
    setPage("your_Next_Page_Bookmark")
}

// Set the channelType to MESSAGE or STREAM
val channelType = RtmChannelType.MESSAGE
mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, object : ResultCallback<GetOnlineUsersResult> {
    override fun onSuccess(result: GetOnlineUsersResult) {
        // If nextPage exists, fill the value of nextPage into the page field of getOnlineUsersOptions for the next getOnlineUsers call
        log(CALLBACK, "getOnlineUsers success")
        log(INFO, "next page: $\{result.nextPage\}")
        for (state in result.userStateList) {
            log(INFO, "user id: $\{state.userId\}")
            state.states.forEach { (key, value) ->
                log(INFO, "key: $key, value: $value")
            }
        }
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includeState and includeUserId in PresenceOptions to false.

PresenceOptions options = new PresenceOptions();
options.setIncludeUserId(false);
options.setIncludeState(false);

// Set the channelType to MESSAGE or STREAM
RtmChannelType channelType = RtmChannelType.MESSAGE;
mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, new ResultCallback<GetOnlineUsersResult>() {
    @Override
    public void onSuccess(GetOnlineUsersResult result) {
        log(CALLBACK, "Total occupancy: " + result.getTotalOccupancy());
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

val options = PresenceOptions().apply {
    setIncludeUserId(false)
    setIncludeState(false)
}

// Set the channelType to MESSAGE or STREAM
val channelType = RtmChannelType.MESSAGE
mRtmClient.getPresence().getOnlineUsers(channelName, channelType, options, object : ResultCallback<GetOnlineUsersResult> {
    override fun onSuccess(result: GetOnlineUsersResult) {
        log(CALLBACK, "Total occupancy: $\{result.totalOccupancy\}")
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

mRtmClient.getPresence().getUserChannels("userid", new ResultCallback<ArrayList<ChannelInfo>>() {
    @Override
    public void onSuccess(ArrayList<ChannelInfo> channels) {
        log(CALLBACK, "get getUserChannels success");
        for (ChannelInfo channel : channels) {
            log(INFO, channel.toString());
        }
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

mRtmClient.getPresence().getUserChannels("userid", object : ResultCallback<ArrayList<ChannelInfo>> {
    override fun onSuccess(channels: ArrayList<ChannelInfo>) {
        log(CALLBACK, "get getUserChannels success")
        for (channel in channels) {
            log(INFO, channel.toString())
        }
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Set status

HashMap<String, String> items = new HashMap<String, String>();
items.put("Mode", "Happy");
items.put("Mic", "False");

mRtmClient.getPresence().setState("channel_name", RtmChannelType.MESSAGE, items, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        log(CALLBACK, "setState success");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

val items = HashMap<String, String>()
items["Mode"] = "Happy"
items["Mic"] = "False"

mRtmClient.getPresence().setState("channel_name", RtmChannelType.MESSAGE, items, object : ResultCallback<Void> {
    override fun onSuccess(responseInfo: Void?) {
        log(CALLBACK, "setState success")
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key-value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

String userId = "Tony";
mRtmClient.getPresence().getState("Chat_room", RtmChannelType.MESSAGE, userId, new ResultCallback<UserState>() {
    @Override
    public void onSuccess(UserState state) {
        log(CALLBACK, "get users(" + state.getUserId() + ") state success, " + state.toString());
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

val userId = "Tony"
mRtmClient.getPresence().getState("Chat_room", RtmChannelType.MESSAGE, userId, object : ResultCallback<UserState> {
    override fun onSuccess(state: UserState) {
        log(CALLBACK, "get users($\{state.userId\}) state success, $\{state.toString()\}")
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

Use the getState method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, a PRESENCE_USER_NOT_EXIST error message is returned by the SDK.

Delete status

Each user can set up to 32 key-value pairs in a channel. To remove items that are no longer needed, call removeState with a list of keys. The removeState method only deletes temporary user status data for the local user.

ArrayList<String> keys = new ArrayList&lt;&gt;(Arrays.asList("Mode", "Mic"));
mRtmClient.getPresence().removeState("Chat_room", RtmChannelType.MESSAGE, keys, new ResultCallback<Void>() {
    @Override
    public void onSuccess(Void responseInfo) {
        log(CALLBACK, "removeState success");
    }

    @Override
    public void onFailure(ErrorInfo errorInfo) {
        log(ERROR, errorInfo.toString());
    }
});

val keys = ArrayList(listOf("Mode", "Mic"))
mRtmClient.getPresence().removeState("Chat_room", RtmChannelType.MESSAGE, keys, object : ResultCallback<Void> {
    override fun onSuccess(responseInfo: Void?) {
        log(CALLBACK, "removeState success")
    }

    override fun onFailure(errorInfo: ErrorInfo) {
        log(ERROR, errorInfo.toString())
    }
})

Receive presence event notifications

A presence event notification returns the PresenceEvent data structure, which includes the RtmPresenceEventType parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

{
      eventType: RtmPresenceEventType.REMOTE_JOIN;
      channelType: RtmChannelType.MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateItems: {};
      interval: {
          joinUserList:[],
          leaveUserList:[],
          timeoutUserList:[],
          userStateList:[],
      };
      snapshot: {
          userStateList:[]
      };
      timestamp: 1710487149497;
}

{
      eventType: RtmPresenceEventType.REMOTE_LEAVE;
      channelType: RtmChannelType.MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateItems: {};
      interval: {
          joinUserList:[],
          leaveUserList:[],
          timeoutUserList:[],
          userStateList:[],
      };
      snapshot: {
          userStateList:[]
      };
      timestamp: 1710487149497;
}

{
      eventType: RtmPresenceEventType.REMOTE_TIMEOUT;
      channelType: RtmChannelType.MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateItems: {};
      interval: {
          joinUserList:[],
          leaveUserList:[],
          timeoutUserList:[],
          userStateList:[],
      };
      snapshot: {
          userStateList:[]
      };
      timestamp: 1710487149497;
}

{
      eventType: RtmPresenceEventType.SNAPSHOT;
      channelType: RtmChannelType.MESSAGE;
      channelName: "test_channel";
      publisher: "";
      stateItems: {};
      interval: {
          joinUserList:[],
          leaveUserList:[],
          timeoutUserList:[],
          userStateList:[],
      };
      snapshot: {
          userStateList:[
              {
                  userId: "user_a",
                  states: {}
              },
              {
                  userId: "user_b",
                  states: {
                      key: "key_1";
                      value: "value_1";
                  }
              },
              {
                  userId: "yourSelf",
                  states: {}
              },
          ]
      };
      timestamp: 1710487149497;
}

{
      eventType: RtmPresenceEventType.REMOTE_STATE_CHANGED;
      channelType: RtmChannelType.MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateItems: {
          "key_1":"value_1";
      };
      interval: {
          joinUserList:[],
          leaveUserList:[],
          timeoutUserList:[],
          userStateList:[],
      };
      snapshot: {
          userStateList:[]
      };
     timestamp: 1710487149497;
}

Scheduled notification mode

{
      eventType: RtmPresenceEventType.INTERVAL,
      channelTye: RtmChannelType.MESSAGE,
      channelName: "Chat_room",
      publisher: "",
      stateItems: {},
      interval: {
          joinUserList: ["Tony", "Lily"],
          leaveUserList: ["Jason"],
          timeoutUserList: ["Wang"],
          userStateList: [
              {
                  userId: "Harvard",
                  states: [
                      {
                          key: "Mic",
                          value: "False"
                      },
                     {
                          key: "Position",
                          value: "Beijing"
                      }
                 ]
              }
          ]
      },
      snapshot: {
          userStateList: []
      },
      timestamp: 1710487149497
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through didReceivePresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = true
presenceOptions.includeUserId = true

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers(channelName: "your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")
        let userCount = response?.totalOccupancy ?? 0
        let userStates = response?.userStateList ?? []

        // You can process userCount and userStates here
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRmPresenceOptions* presence_opt = [[AgoraRtmPresenceOptions alloc] init];
presence_opt.includeState = true;
presence_opt.includeUserId = true;
[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
        NSArray<AgoraRtmUserState *> * user_states = response.userStateList;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the response.nextPage field contains a bookmark for the next page. After each query, check response.nextPage to determine if there is more data. To retrieve the next page, set the page field in AgoraRtmPresenceOptions to the value of response.nextPage. Repeat this process until response.nextPage is empty.

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = true
presenceOptions.includeUserId = true
presenceOptions.page = "your_Next_Page_Bookmark"

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers("your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")

        let userCount = response?.totalOccupancy ?? 0
        let nextPage = response?.nextPage ?? ""
        let userStates = response?.userStateList ?? []

        // You can process userCount, nextPage, and userStates here
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRtmPresenceOptions* presence_opt = [[AgoraRtmPresence alloc] init];
presence_opt.includeState = true;
presence_opt.includeUserId = true;
presence_opt.page = @"your_Next_Page_Bookmark";

[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
        NSString* next_page = response.nextPage;
        NSArray<AgoraRtmUserState *> * user_states = response.userStateList;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includeState and includeUserId in AgoraRtmPresenceOptions to false.

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = false
presenceOptions.includeUserId = false

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers(channelName: "your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")

        let userCount = response?.totalOccupancy ?? 0
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRtmPresenceOptions* presence_opt = [[AgoraRtmPresence alloc] init];
presence_opt.includeState = false;
presence_opt.includeUserId = false;

[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

rtm.getPresence()?.getUserChannels("userId") { response, errorInfo in
    if errorInfo == nil {
        print("getUserChannels success!!")

        let channelCount = response?.totalChannel ?? 0
        let channels = response?.channels ?? []

    } else {
        print("getUserChannels failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

[[rtm getPresence] getUserChannels:@"userId" completion:^(AgoraRtmGetUserChannelsResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getUserChannels success!!");
        int channel_count = response.totalChannel;
        NSArray<AgoraRtmChannelInfo *> * channels = response.channels;
    } else {
        NSLog(@"getUserChannels failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Signaling does not permanently save the status data. When a user unsubscribes from a channel, times out, or exits a channel, the data is deleted. To save user data permanently, refer to Store user metadata.

When a user's temporary status changes, Signaling triggers the remote state changed event notification in real-time. Users who enable presence in features when subscribing to a channel, receive the event notification.

Set status

let states: [String: String] = ["key1": "value1", "key2": "value2"]

rtm.getPresence()?.setState(channelName: "your_channel", channelType: .message, items: states) { response, errorInfo in
    if errorInfo == nil {
        print("setState success!!")
    } else {
        print("setState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

NSDictionary *states = @{@"key1": @"value1", @"key2": @"value2"};

[[rtm getPresence] setState:@"your_channel" channelType:AgoraRtmChannelTypeMessage items:states completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"setState success!!");
    } else {
        NSLog(@"setState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key-value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

rtm.getPresence()?.getState(channelName: "Chat_room", channelType: .message, userId: "userid") { response, errorInfo in
    if errorInfo == nil {
        print("getState success!!")

        if let state = response?.state {
            // process state
        }
    } else {
        print("getState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

If the queried user is not present in the specified channel, a presenceUserNotExist error message is returned by the SDK.

[[rtm getPresence] getState:@"Chat_room" channelType:AgoraRtmChannelTypeMessage userId:@"userid" completion:^(AgoraRtmPresenceGetStateResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getState success!!");
        AgoraRtmUserState* state = response.state;
    } else {
        NSLog(@"getState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

Use the getState method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, a AgoraRtmErrorPresenceUserNotExist error message is returned by the SDK.

Delete status

let keys: [String] = ["key1", "key2"]

rtm.getPresence()?.removeState("your_channel", channelType: .message, keys: keys) { response, errorInfo in
    if errorInfo == nil {
        print("removeState success!!")
    } else {
        print("removeState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

Both the setState and removeState methods trigger remoteStateChanged event notifications. Users who join the channel with presence enabled in features receive event notifications containing full data of the user's temporary status.

NSArray<NSString*>* keys = @[@"key1", @"key2"];
[[rtm getPresence] removeState:@"your_channel" channelType:AgoraRtmChannelTypeMessage keys:keys completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"removeState success!!");
    } else {
        NSLog(@"removeState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

Both the setState and removeState methods trigger AgoraRtmPresenceEventTypeRemoteStateChanged event notifications. Users who subscribe to the channel with presence enabled in features receive event notifications containing full data of the user's temporary status.

Receive presence event notifications

A presence event notification returns the AgoraRtmPresenceEvent data structure, which includes the AgoraRtmPresenceEventType parameter.

To receive presence event notifications, implement an event listener. See event listeners for details. In addition, include presence in the features parameter when subscribing to or joining a channel.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Set the Max number of instant event value in Agora Console to specify the condition for switching between the two modes. The scheduled notification mode helps prevent event noise that results from a large number of online users in the channel. See Presence configuration for details.

Real-time notification mode

Swift

remoteJoinChannel
remoteLeaveChannel
remoteConnectionTimeout
remoteStateChanged

{
    type: .remoteJoinChannel;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    states: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .remoteLeaveChannel;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    stateChanged: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .remoteConnectionTimeout;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    stateChanged: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .snapshot;
    channelType: .message;
    channelName: "test_channel";
    publisher: "";
    stateChanged: [];
    interval: [];
    snapshot: [
        { userId: "user_a", states: {}},
        { userId: "user_b", states: { key_1: "value_1" }},
        { userId: "yourSelf", states: {}},
    ];
    timestamp: 1710487149497;
}

{
    eventType: .remoteStateChanged;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    states: {
        "key_1": "value_1",
    };
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

Objective-C

AgoraRtmPresenceEventTypeRemoteJoinChannel
AgoraRtmPresenceEventTypeRemoteLeaveChannel
AgoraRtmPresenceEventTypeRemoteConnectionTimeout
AgoraRtmPresenceEventTypeRemoteStateChanged

{
      type: AgoraRtmPresenceEventTypeRemoteJoinChannel;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteLeaveChannel;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteConnectionTimeout;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeSnapshot;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "";
      stateChanged: [];
      interval: [];
      snapshot: [
          { userId: "user_a", states: {}},
          { userId: "user_b", states: { key_1: "value_1" }},
          { userId: "yourSelf", states: {}},
      ];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteStateChanged;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: {
          "key_1": "value_1",
      };
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

Scheduled notification mode

When the number of online users in a channel exceeds the Max number of instant event value, the channel switches to the scheduled notification mode. In this mode, remoteJoinChannel, remoteLeaveChannel, remoteConnectionTimeout, and remoteStateChanged events are replaced by interval events and sent to all users in the channel at specific time intervals. Users receive the following notification:

{
      "type": "AgoraRtmPresenceEventTypeInterval",
      "channelType": "AgoraRtmChannelTypeMessages",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "True" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      }
}

When the number of online users in the channel exceeds the Max number of instant event value, the channel switches to the scheduled notification mode. In this mode, AgoraRtmPresenceEventTypeRemoteJoinChannel, AgoraRtmPresenceEventTypeRemoteLeaveChannel, AgoraRtmPresenceEventTypeRemoteConnectionTimeout, and AgoraRtmPresenceEventTypeRemoteStateChanged events are replaced by AgoraRtmPresenceEventTypeInterval events and sent to all users in the channel at specific time intervals. Users receive the following notification:

{
      "type": "AgoraRtmPresenceEventTypeInterval",
      "channelType": "AgoraRtmChannelTypeMessages",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "True" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      }
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through didReceivePresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = true
presenceOptions.includeUserId = true

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers(channelName: "your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")
        let userCount = response?.totalOccupancy ?? 0
        let userStates = response?.userStateList ?? []

        // You can process userCount and userStates here
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRmPresenceOptions* presence_opt = [[AgoraRtmPresenceOptions alloc] init];
presence_opt.includeState = true;
presence_opt.includeUserId = true;
[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
        NSArray<AgoraRtmUserState *> * user_states = response.userStateList;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = true
presenceOptions.includeUserId = true
presenceOptions.page = "your_Next_Page_Bookmark"

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers("your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")

        let userCount = response?.totalOccupancy ?? 0
        let nextPage = response?.nextPage ?? ""
        let userStates = response?.userStateList ?? []

        // You can process userCount, nextPage, and userStates here
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRtmPresenceOptions* presence_opt = [[AgoraRtmPresence alloc] init];
presence_opt.includeState = true;
presence_opt.includeUserId = true;
presence_opt.page = @"your_Next_Page_Bookmark";

[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
        NSString* next_page = response.nextPage;
        NSArray<AgoraRtmUserState *> * user_states = response.userStateList;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includeState and includeUserId in AgoraRtmPresenceOptions to false.

let presenceOptions = AgoraRtmPresenceOptions()
presenceOptions.includeState = false
presenceOptions.includeUserId = false

// Retrieve the user state of the current channel
rtm.getPresence()?.getOnlineUsers(channelName: "your_channel", channelType: .message, options: presenceOptions) { response, errorInfo in
    if errorInfo == nil {
        print("getOnlineUsers success!!")

        let userCount = response?.totalOccupancy ?? 0
    } else {
        print("getOnlineUsers failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

AgoraRtmPresenceOptions* presence_opt = [[AgoraRtmPresence alloc] init];
presence_opt.includeState = false;
presence_opt.includeUserId = false;

[[rtm getPresence] getOnlineUsers:@"your_channel" channelType:AgoraRtmChannelTypeMessage options:presence_opt completion:^(AgoraRtmgetOnlineUsersResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getOnlineUsers success!!");
        int user_count = response.totalOccupancy;
    } else {
        NSLog(@"getOnlineUsers failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

rtm.getPresence()?.getUserChannels("userId") { response, errorInfo in
    if errorInfo == nil {
        print("getUserChannels success!!")

        let channelCount = response?.totalChannel ?? 0
        let channels = response?.channels ?? []

    } else {
        print("getUserChannels failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

[[rtm getPresence] getUserChannels:@"userId" completion:^(AgoraRtmGetUserChannelsResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getUserChannels success!!");
        int channel_count = response.totalChannel;
        NSArray<AgoraRtmChannelInfo *> * channels = response.channels;
    } else {
        NSLog(@"getUserChannels failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Set status

let states: [String: String] = ["key1": "value1", "key2": "value2"]

rtm.getPresence()?.setState(channelName: "your_channel", channelType: .message, items: states) { response, errorInfo in
    if errorInfo == nil {
        print("setState success!!")
    } else {
        print("setState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

NSDictionary *states = @{@"key1": @"value1", @"key2": @"value2"};

[[rtm getPresence] setState:@"your_channel" channelType:AgoraRtmChannelTypeMessage items:states completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"setState success!!");
    } else {
        NSLog(@"setState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key-value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

rtm.getPresence()?.getState(channelName: "Chat_room", channelType: .message, userId: "userid") { response, errorInfo in
    if errorInfo == nil {
        print("getState success!!")

        if let state = response?.state {
            // process state
        }
    } else {
        print("getState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

If the queried user is not present in the specified channel, a presenceUserNotExist error message is returned by the SDK.

[[rtm getPresence] getState:@"Chat_room" channelType:AgoraRtmChannelTypeMessage userId:@"userid" completion:^(AgoraRtmPresenceGetStateResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"getState success!!");
        AgoraRtmUserState* state = response.state;
    } else {
        NSLog(@"getState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

Delete status

let keys: [String] = ["key1", "key2"]

rtm.getPresence()?.removeState("your_channel", channelType: .message, keys: keys) { response, errorInfo in
    if errorInfo == nil {
        print("removeState success!!")
    } else {
        print("removeState failed, errorCode \\(errorInfo!.errorCode), reason \\(errorInfo!.reason)")
    }
}

NSArray<NSString*>* keys = @[@"key1", @"key2"];
[[rtm getPresence] removeState:@"your_channel" channelType:AgoraRtmChannelTypeMessage keys:keys completion:^(AgoraRtmCommonResponse * _Nullable response, AgoraRtmErrorInfo * _Nullable errorInfo) {
    if (errorInfo == nil) {
        NSLog(@"removeState success!!");
    } else {
        NSLog(@"removeState failed, errorCode %d, reason %@", errorInfo.errorCode, errorInfo.reason);
    }
}];

Receive presence event notifications

A presence event notification returns the AgoraRtmPresenceEvent data structure, which includes the AgoraRtmPresenceEventType parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

Swift

remoteJoinChannel
remoteLeaveChannel
remoteConnectionTimeout
remoteStateChanged

{
    type: .remoteJoinChannel;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    states: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .remoteLeaveChannel;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    stateChanged: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .remoteConnectionTimeout;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    stateChanged: [];
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

{
    eventType: .snapshot;
    channelType: .message;
    channelName: "test_channel";
    publisher: "";
    stateChanged: [];
    interval: [];
    snapshot: [
        { userId: "user_a", states: {}},
        { userId: "user_b", states: { key_1: "value_1" }},
        { userId: "yourSelf", states: {}},
    ];
    timestamp: 1710487149497;
}

{
    eventType: .remoteStateChanged;
    channelType: .message;
    channelName: "test_channel";
    publisher: "publisher_name";
    states: {
        "key_1": "value_1",
    };
    interval: [];
    snapshot: [];
    timestamp: 1710487149497;
}

Objective-C

AgoraRtmPresenceEventTypeRemoteJoinChannel
AgoraRtmPresenceEventTypeRemoteLeaveChannel
AgoraRtmPresenceEventTypeRemoteConnectionTimeout
AgoraRtmPresenceEventTypeRemoteStateChanged

{
      type: AgoraRtmPresenceEventTypeRemoteJoinChannel;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteLeaveChannel;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteConnectionTimeout;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeSnapshot;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "";
      stateChanged: [];
      interval: [];
      snapshot: [
          { userId: "user_a", states: {}},
          { userId: "user_b", states: { key_1: "value_1" }},
          { userId: "yourSelf", states: {}},
      ];
      timestamp: 1710487149497;
}

{
      eventType: AgoraRtmPresenceEventTypeRemoteStateChanged;
      channelType: AgoraRtmChannelTypeMessage;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: {
          "key_1": "value_1",
      };
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

Scheduled notification mode

{
      "type": "AgoraRtmPresenceEventTypeInterval",
      "channelType": "AgoraRtmChannelTypeMessages",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "True" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      }
}

{
      "type": "AgoraRtmPresenceEventTypeInterval",
      "channelType": "AgoraRtmChannelTypeMessages",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "True" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      }
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through presence event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

final channelName = 'chat_room';
try {
    var (status,response) = await rtmClient.getPresence.getOnlineUsers(
        channelName,
        RtmChannelType.message,
        includeUserId:true,
        includeState:true );
    if (status == true){
        print('${status.operation} failed, errorCode: ${status.errorCode}, due to ${status.reason}');
    } else {
        // If a nextPage exists, the next time getOnlineUsers is called, the value of nextPage should be filled in the page field
        var nextPage = response.nextPage;
        var count = response.count;
        var userStateList = response.userStateList;
        userStateList.forEach((userState) {
            print(`${userState.userId} has states: ${userState.states}`);
        });
    }
} catch (e) {
    print('something went wrong: $e');
}

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the nextPage field in the returned response contains a bookmark for the next page. After each query, check if response.getNextPage is empty to determine if there is more data. To retrieve the next page, set the page parameter in getOnlineUsers to the value of response.getNextPage. Repeat this process until response.getNextPage is null. Refer to the following code:

final channelName = 'chat_room';
try {
    var (status,response) = await rtmClient.getPresence.getOnlineUsers(
        channelName,
        RtmChannelType.message,
        includeUserId: true,
        includeState: true
        page: 'your_Next_Page_Bookmark'); // Next page bookmark from the previous call
    if (status == true){
        print('${status.operation} failed, errorCode: ${status.errorCode}, due to ${status.reason}');
    } else {
        // If a nextPage exists, the next time getOnlineUsers is called, the value of nextPage should be filled in the page field
        var nextPage = response.nextPage;
        var count = response.count;
        var userStateList = response.userStateList;
        userStateList.forEach((userState) {
            print(`${userState.userId} has states: ${userState.states}`);
        });
    }
} catch (e) {
    print('something went wrong: $e');
}

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary statuses. To get the total channel occupancy, set includeState and includeUserId in getOnlineUsers to false.

final channelName = 'chat_room';
try {
    var (status,response) = await rtmClient.getPresence.getOnlineUsers(
        channelName,
        RtmChannelType.message,
        includeUserId: false,
        includeState: false);

    if (status == true){
        print('${status.operation} failed, errorCode: ${status.errorCode}, due to ${status.reason}');
    } else {
        var nextPage = response.nextPage;
        var count = response.count;
        print('There are $count occupants in $channelName channel');
    }
} catch (e) {
    print('something went wrong: $e');
}

In this case, only the count property in the response is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

try {
    var (status,response) = await rtmClient.getPresence.getUserChannels("Tony");
    if (status == true){
        print('${status.operation} failed, errorCode: ${status.errorCode}, due to ${status.reason}');
    } else {
        var channels = response.channels;
        var count = response.count;
        channels.forEach((channelInfo) {
            print('${channelInfo.channelName}:${channelInfo.channelType}')
        });
    }
} catch (e) {
    print('something went wrong: $e');
}

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

When a user's temporary status changes, Signaling triggers a remoteStateChanged event notification in real time. Users who set withPresence = true when joining the channel, receive the event notification.

Set status

var states = {
    'Mode': 'Happy',
    'Mic': 'False',
};
final channelName = 'chat_room';
try {
    var (status,response) = await rtmClient.getPresence.setState(
        channelName,
        RtmChannelType.message,
        states);
    if (status == true){
        print('${status.operation} failed,errorCode: ${status.errorCode},due to ${status.reason}');
    } else {
        print('set states success!');
    }
} catch (e) {
    print('something went wrong: $e');
}

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key/value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

final channelName = 'chat_room';
try {
    var (status,response) = await rtmClient.getPresence.getState(
        channelName,
        RtmChannelType.message,
        'Tony');
    if (status == true){
        print('${status.operation} failed,errorCode: ${status.errorCode},due to ${status.reason}');
    } else {
        var userState = response.state;
        print('States for ${userState.userId}: ${userState.states}');
    }
} catch (e) {
    print('something went wrong: $e');
}

If the queried user is not present in the specified channel, a presenceUserNotExist error message is returned by the SDK.

Delete status

final channelName = 'chat_room';
final states = ['Mode','Mic'];
try {
    var (status,response) = await rtmClient.getPresence.removeState(
        channelName,
        RtmChannelType.message,
        states: states);
    if (status == true){
        print('${status.operation} failed,errorCode: ${status.errorCode},due to ${status.reason}');
    } else {
        var userState = response.state;
        print('remove states success!');
    }
} catch (e) {
    print('something went wrong: $e');
}

Both the setState and removeState methods trigger remoteStateChanged event notifications. Users who join the channel with withPresence set to true receive event notifications containing full data of the user's temporary status.

Receive presence event notifications

A presence event notification returns the PresenceEvent data structure, which includes the RtmPresenceEventType parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

If the number of instant notifications in the channel is less than the Max number of instant event value, presence event notifications operate in real-time notification mode. In this mode, remoteJoinChannel, remoteLeaveChannel, remoteTimeout, and remoteStateChanged notifications are sent to the client in real-time.

{
    type: RtmPresenceEventType.remoteJoinChannel,
    channelType: RtmChannelType.message,
    channelName: 'chat_room',
    publisher: 'Tony',
    stateItems: [],
    interval: [],
    snapshot: [],
    timestamp: 1710487149497,
}

{
    type: RtmPresenceEventType.remoteLeaveChannel,
    channelType: RtmChannelType.message,
    channelName: 'chat_room',
    publisher: 'Tony',
    stateItems: [],
    interval: [],
    snapshot: [],
    timestamp: 1710487149497,
}

{
    type: RtmPresenceEventType.remoteTimeout,
    channelType: RtmChannelType.message,
    channelName: 'chat_room',
    publisher: 'Tony',
    stateItems: [],
    interval: [],
    snapshot: [],
    timestamp: 1710487149497,
}

{
    type: RtmPresenceEventType.snapshot,
    channelType: RtmChannelType.message,
    channelName: 'chat_room',
    publisher: 'Tony',
    stateItems: [],
    interval: [],
    snapshot: {[
        { userId: "user_a", states: []},
        { userId: "user_b", states: [{ key: 'mic', value : 'on'}]},
        { userId: "yourSelf", states: [{}]},
    ]},
    timestamp: 1710487149497
}

{
    type: RtmPresenceEventType.remoteStateChanged,
    channelType: RtmChannelType.message,
    channelName: 'chat_room',
    publisher: 'Tony',
    stateItems: [{ key: 'mic', value : 'on'},{ key: 'mode', value : 'happy'}],
    interval: [],
    snapshot: [],
    timestamp: 1710487149497
}

Scheduled notification mode

When the number of online users in the channel exceeds the Max number of instant event value, the channel switches to the scheduled notification mode. In this mode, remoteJoinChannel, remoteLeaveChannel, remoteTimeout, and remoteStateChanged events are replaced by interval events and sent to all users in the channel at specific time intervals. Users receive the following notification:

{
    type : RtmPresenceEventType.interval,
    channelTye : RtmChannelType.message,,
    channelName : 'chat_room',
    publisher : 'Tony',
    interval : {
        joinUserList : {users:['Tony','Lily']},
        leaveUserList :{users:['Jason']},
        timeoutUserList : {users:['Wang']},
        userStateList : [
            {
                userId : 'Harvard',
                states :  [{ key: 'mic', value : 'on'},{ key: 'mode', value : 'happy'}],
            },
            {
                userId : 'Harvard',
                states :  [{ key: 'mic', value : 'off'},{ key: 'mode', value : 'sad'}],
            }
        ]
    }
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through onPresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

PresenceOptions options;
options.includeState = true;
options.includeUserId =true;

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

After you call this method, the SDK triggers the onGetOnlineUsersResult callback to return the call result.

class RtmEventHandler : public IRtmEventHandler {
    void onGetOnlineUsersResult(const uint64_t requestId, const UserState *userStateList, const size_t count, const char *nextPage, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("getOnlineUsers failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("getOnlineUsers success\n");
            for (int i = 0 ;i < count; i++) {
                printf("user: %s\n", userStateList[i].userId);
                for (int j = 0 ; j < userStateList[i].statesCount; j++) {
                    printf("key: %s value: %s\n", userStateList[i].states[j].key, userStateList[i].states[j].value);
                }
            }
        }
    }
};

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the nextPage field in the returned result contains a bookmark for the next page. After each query, check if nextPage is not empty to determine if there is more data. To retrieve the next page, set the page field in PresenceOptions to the value of nextPage. Repeat this process until nextPage is null. Refer to the following code:

PresenceOptions options;
options.includeState = true;
options.includeUserId =true;
options.page = "your_Next_Page_Bookmark";

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includeState and includeUserId in PresenceOptions to false.

PresenceOptions options;
options.includeState = false;
options.includeUserId =false;

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

uint64_t requestId;
rtmClient->getPresence()->getUserChannels("tony", requestId);

After you call this method, the SDK triggers the onGetUserChannelsResult callback to return the call result.

class RtmEventHandler : public IRtmEventHandler {
    void onGetUserChannelsResult(const uint64_t requestId, const ChannelInfo *channels, const size_t count, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("getUserChannels failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("getUserChannels success\n");
            for (int i = 0; i < count; i++) {
                printf("channel: %s channel type: %d\n", channels[i].channelName, channels[i].channelType);
            }
        }
    }
};

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

When a user's temporary status changes, Signaling triggers an RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED event notification in real-time. Users who set withPresence = true when joining the channel, receive the event notification.

Set status

std::vector<StateItem> items;
StateItem item;
item.key = "Mode";
item.value = "Happy";
items.emplace_back(item);

uint64_t requestId;
rtm_client->getPresence()->setState("channelName", RTM_CHANNEL_TYPE_MESSAGE, items.data(), items.size(), requestId);

After you call this method, the SDK triggers the onPresenceSetStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
    void onPresenceSetStateResult(const uint64_t requestId, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("SetState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("SetState success\n");
        }
    }
};

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key/value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

uint64_t requestId;
rtm_client->getPresence()->getState("channelName", RTM_CHANNEL_TYPE_MESSAGE, "tony", requestId);

After you call this method, the SDK triggers the onPresenceGetStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
    void onPresenceGetStateResult(const uint64_t requestId, const UserState &state, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("GetState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("GetState user id: %s success\n", state.userId);
            for (int i = 0; i < state.statesCount; i++) {
                printf("key: %s, value: %s\n", state.states[i].key, state.states[i].value);
            }
        }
    }
};

Use the getState method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, an error message is returned by the SDK.

Delete status

std::vector<const char*> keys;
keys.push_back("Mode");
keys.push_back("Mic");

uint64_t requestId;
rtmClient->getPresence()->removeState("channelName", RTM_CHANNEL_TYPE_MESSAGE, keys.data(), keys.size(), requestId);

After you call this method, the SDK triggers the onPresenceRemoveStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
void onPresenceRemoveStateResult(const uint64_t requestId, RTM_ERROR_CODE errorCode) override {
    if (errorCode != RTM_ERROR_OK) {
        printf("RemoveState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
    } else {
        printf("RemoveState success\n");
    }
}
};

Both the setState and removeState methods trigger RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED event notifications. Users who join the channel with withPresence set to true receive event notifications containing full data of the user's temporary status.

Receive presence event notifications

A presence event notification returns the PresenceEvent data structure, which includes the RTM_PRESENCE_EVENT_TYPE. parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

If the number of instant notifications in the channel is less than the Max number of instant event value, presence event notifications operate in real-time notification mode. In this mode, RTM_PRESENCE_EVENT_TYPE_REMOTE_JOIN_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_LEAVE_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_TIMEOUT, and RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED notifications are sent to the client in real-time.

{
      type: RTM_PRESENCE_EVENT_TYPE_REMOTE_JOIN_CHANNEL;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_LEAVE_CHANNEL;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_TIMEOUT;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_SNAPSHOT;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "";
      stateChanged: [];
      interval: [];
      snapshot: [
          { userId: "user_a", states: {}},
          { userId: "user_b", states: { key_1: "value_1" }},
          { userId: "yourSelf", states: {}},
      ];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: {
          "key_1": "value_1",
      };
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

Scheduled notification mode

When the number of online users in the channel exceeds the Max number of instant event value, the channel switches to the scheduled notification mode. In this mode, RTM_PRESENCE_EVENT_TYPE_REMOTE_JOIN_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_LEAVE_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_TIMEOUT, and RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED events are replaced by RTM_PRESENCE_EVENT_TYPE_INTERVAL events and sent to all users in the channel at specific time intervals. Users receive the following notification:

{
      "type": "RTM_PRESENCE_EVENT_TYPE_INTERVAL",
      "channelType": "RTM_CHANNEL_TYPE_MESSAGE",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      },
      "snapshot": {
          "userStateList": []
      },
      "timestamp": 1710487149497
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

After obtaining the initial online users list, update it in real time through onPresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

PresenceOptions options;
options.includeState = true;
options.includeUserId =true;

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

After you call this method, the SDK triggers the onGetOnlineUsersResult callback to return the call result.

class RtmEventHandler : public IRtmEventHandler {
    void onGetOnlineUsersResult(const uint64_t requestId, const UserState *userStateList, const size_t count, const char *nextPage, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("getOnlineUsers failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("getOnlineUsers success\n");
            for (int i = 0 ;i < count; i++) {
                printf("user: %s\n", userStateList[i].userId);
                for (int j = 0 ; j < userStateList[i].statesCount; j++) {
                    printf("key: %s value: %s\n", userStateList[i].states[j].key, userStateList[i].states[j].value);
                }
            }
        }
    }
};

The getOnlineUsers method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the nextPage field in the returned result contains a bookmark for the next page. After each query, check if nextPage is not empty to determine if there is more data. To retrieve the next page, set the page field in PresenceOptions to the value of nextPage. Repeat this process until nextPage is null. Refer to the following code:

PresenceOptions options;
options.includeState = true;
options.includeUserId =true;
options.page = "your_Next_Page_Bookmark";

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set includeState and includeUserId in PresenceOptions to false.

PresenceOptions options;
options.includeState = false;
options.includeUserId =false;

uint64_t requestId;
rtmClient->getPresence()->getOnlineUsers("channelName", RTM_CHANNEL_TYPE_MESSAGE, options, requestId);

In this case, only the totalOccupancy property in the result is valid while all other fields are empty.

You cannot set includeState to true and includeUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

uint64_t requestId;
rtmClient->getPresence()->getUserChannels("tony", requestId);

After you call this method, the SDK triggers the onGetUserChannelsResult callback to return the call result.

class RtmEventHandler : public IRtmEventHandler {
    void onGetUserChannelsResult(const uint64_t requestId, const ChannelInfo *channels, const size_t count, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("getUserChannels failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("getUserChannels success\n");
            for (int i = 0; i < count; i++) {
                printf("channel: %s channel type: %d\n", channels[i].channelName, channels[i].channelType);
            }
        }
    }
};

The getUserChannels method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Set status

std::vector<StateItem> items;
StateItem item;
item.key = "Mode";
item.value = "Happy";
items.emplace_back(item);

uint64_t requestId;
rtm_client->getPresence()->setState("channelName", RTM_CHANNEL_TYPE_MESSAGE, items.data(), items.size(), requestId);

After you call this method, the SDK triggers the onPresenceSetStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
    void onPresenceSetStateResult(const uint64_t requestId, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("SetState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("SetState success\n");
        }
    }
};

When using setState to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key/value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the getState method:

uint64_t requestId;
rtm_client->getPresence()->getState("channelName", RTM_CHANNEL_TYPE_MESSAGE, "tony", requestId);

After you call this method, the SDK triggers the onPresenceGetStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
    void onPresenceGetStateResult(const uint64_t requestId, const UserState &state, RTM_ERROR_CODE errorCode) override {
        if (errorCode != RTM_ERROR_OK) {
            printf("GetState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
        } else {
            printf("GetState user id: %s success\n", state.userId);
            for (int i = 0; i < state.statesCount; i++) {
                printf("key: %s, value: %s\n", state.states[i].key, state.states[i].value);
            }
        }
    }
};

Use the getState method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, an error message is returned by the SDK.

Delete status

std::vector<const char*> keys;
keys.push_back("Mode");
keys.push_back("Mic");

uint64_t requestId;
rtmClient->getPresence()->removeState("channelName", RTM_CHANNEL_TYPE_MESSAGE, keys.data(), keys.size(), requestId);

After you call this method, the SDK triggers the onPresenceRemoveStateResult callback to return the API call result.

class RtmEventHandler : public IRtmEventHandler {
void onPresenceRemoveStateResult(const uint64_t requestId, RTM_ERROR_CODE errorCode) override {
    if (errorCode != RTM_ERROR_OK) {
        printf("RemoveState failed error is %d reason is %s\n", errorCode, getErrorReason(errorCode));
    } else {
        printf("RemoveState success\n");
    }
}
};

Receive presence event notifications

A presence event notification returns the PresenceEvent data structure, which includes the RTM_PRESENCE_EVENT_TYPE. parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

If the number of instant notifications in the channel is less than the Max number of instant event value, presence event notifications operate in real-time notification mode. In this mode, RTM_PRESENCE_EVENT_TYPE_REMOTE_JOIN_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_LEAVE_CHANNEL, RTM_PRESENCE_EVENT_TYPE_REMOTE_TIMEOUT, and RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED notifications are sent to the client in real-time.

{
      type: RTM_PRESENCE_EVENT_TYPE_REMOTE_JOIN_CHANNEL;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_LEAVE_CHANNEL;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_TIMEOUT;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      stateChanged: [];
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_SNAPSHOT;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "";
      stateChanged: [];
      interval: [];
      snapshot: [
          { userId: "user_a", states: {}},
          { userId: "user_b", states: { key_1: "value_1" }},
          { userId: "yourSelf", states: {}},
      ];
      timestamp: 1710487149497;
}

{
      eventType: RTM_PRESENCE_EVENT_TYPE_REMOTE_STATE_CHANGED;
      channelType: RTM_CHANNEL_TYPE_MESSAGE;
      channelName: "test_channel";
      publisher: "publisher_name";
      states: {
          "key_1": "value_1",
      };
      interval: [];
      snapshot: [];
      timestamp: 1710487149497;
}

Scheduled notification mode

{
      "type": "RTM_PRESENCE_EVENT_TYPE_INTERVAL",
      "channelType": "RTM_CHANNEL_TYPE_MESSAGE",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "remote_join": ["Tony", "Lily"],
          "remote_leave": ["Jason"],
          "remote_timeout": ["Wendy"],
          "remote_state_change": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      },
      "snapshot": {
          "userStateList": []
      },
      "timestamp": 1710487149497
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

Get a list of users currently in a channel and their temporary status data.
Get a list of channels a specified user has joined or is subscribed to.
Get, set, or remove user statuses.
Receive real-time event notifications when users join or leave specified channels.
Receive user status change event notifications in real time.

Understand the tech

Presence workflow

Prerequisites

Ensure that you have integrated the Signaling SDK in your project, and implemented the framework functionality from the SDK quickstart page.

Presence features require Signaling SDK version 2.2.0 or later.

Implement presence features

Using presence, you can implement the following features:

Get channel users

To obtain a list of online users in a channel, call GetOnlineUsersAsync. Depending on your parameter settings, this method returns a list of online user IDs in a channel and their temporary status data, or just the number of online users in the channel. You do not need to join a channel to call this method. This method is applicable to both message channels and stream channels. Use the channelType parameter to specify the channel type.

After obtaining the initial online users list, update it in real time through OnPresenceEvent event notifications.

Refer to the following sample code to query the list of online users in a channel and their current status:

var channelType = RTM_CHANNEL_TYPE.MESSAGE;
var options = new PresenceOptions();
options.withState = true;
options.withUserId = true;

var (status,response) = await rtmClient.GetPresence().GetOnlineUsersAsync("Chat_room", channelType, options);
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation));
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));

}
else
{
    Debug.Log(string.Format("You have got {0} users information ", response.TotalOccupancy));
    foreach (UserState user in response.UserStateList)
    {
        Debug.Log("The User ID is:" + user.userId);
        var userstate = user.states;
        foreach(StateItem stateItem in userstate)
        {
            Debug.Log(string.Format("Key: {0}, Value: {1}", stateItem.key,stateItem.value));
        }

    }

    if (response.NextPage != null)
    {
        Debug.Log("you have the next page information waiting for reading!");
    }
}

The GetOnlineUsersAsync method retrieves one page of data at a time. Each page contains up to 100 online users. If the channel has more than 100 users, the NextPage field in the returned response contains a bookmark for the next page. After each query, check if response.NextPage is empty to determine if there is more data. To retrieve the next page, set the page field in PresenceOptions to the value of response.NextPage. Repeat this process until response.NextPage is null. Refer to the following code:

var options = new PresenceOptions();
options.withState = true;
options.withUserId = true;
options.page = "Next_Page_Bookmark";

var (status,response) = await rtmClient.GetPresence().GetOnlineUsersAsync("Chat_room", RTM_CHANNEL_TYPE.MESSAGE, options);
// ...

When there is a large number of users in a channel, you may only care about the total number of online users, and not their identities or temporary status. To get the total channel occupancy, set withState and withUserId in PresenceOptions to false.

var options = new PresenceOptions();
options.withState = false;
options.withUserId = false;
var (status,response) = await rtmClient.GetPresence().GetOnlineUsersAsync("Chat_room", RTM_CHANNEL_TYPE.MESSAGE, options);
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation)    );
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));
}
else
{
    Debug.Log(string.Format("{0} users online ", response.TotalOccupancy));
}

In this case, only the TotalOccupancy property in the response is valid while all other fields are empty.

You cannot set withState to true and withUserId to false at the same time. To get the temporary status of users, you must also retrieve their user IDs.

Get user channels

The GetUserChannelsAsync method enables you to query which channels a user is currently in. This includes the message channels a user has subscribed to and the stream channels they have joined. This method is particularly useful for tracking user paths. Refer to the following sample code:

var (status,response) = await rtmClient.GetPresence().GetUserChannelsAsync("Tony");
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation));
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));
}
else
{
    Debug.Log(string.Format("User Tony is now in {0} channels ", response.Channels.Length));
    if (response.Channels.Length > 0)
    {
        foreach (ChannelInfo channel in response.Channels)
        {
            Debug.Log(string.Format("Channel Name: {0}, Channel Type:{1}", channel.channelName, channel.channelType));
        }
    }
}

The GetUserChannelsAsync method returns complete query results about the channels and their types that the queried user is in, without pagination.

User status management

Set status

Using presence, you can set the temporary user status for the local user. When you set the status before subscribing to or joining a channel, the data is cached on the client and does not take effect immediately. The status is updated and corresponding event notifications are triggered when you subscribe to or join a channel. The SetStateAsync method applies to both message and stream channels; use the channelType parameter to specify the channel type.

StateItem[] myStates = new StateItem[]
{
    new StateItem("Mode","Happy"),
    new StateItem("Mic","False"),
    new StateItem("Score","100"),
};
var (status,response) = await rtmClient.GetPresence().SetStateAsync("Chat_room", RTM_CHANNEL_TYPE.MESSAGE, myStates);
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation));
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));
}
else
{
    Debug.Log("Set State Success!");
}

When using SetStateAsync to set temporary user status, if the specified key already exists, its value is overwritten by the new value. If the specified key does not exist, a new key/value pair is added.

Get status

To obtain the temporary user status set by a user in a specified channel, use the GetStateAsync method:

var (status,response) = await rtmClient.GetPresence().GetStateAsync("Chat_room", RTM_CHANNEL_TYPE.MESSAGE, "Tony");
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation));
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));
}
else
{
    var userState = response.State;
    Debug.Log(string.Format("User:{0}, have stateCount:{1} states",userState.userId, userState.statesCount));
    foreach(StateItem stateItem in userstate.states)
    {
        Debug.Log(string.Format("State Key: {0}, State Value:{1}", stateItem.key,stateItem.value));
    }
}

Use the GetStateAsync method to obtain the temporary status of other online users in the channel. If the queried user is not present in the specified channel, an error message is returned by the SDK.

Delete status

Each user can set up to 32 key/value pairs in a channel. To remove items that are no longer needed, call RemoveStateAsync with a list of keys. The RemoveStateAsync method only deletes temporary user status data for the local user.

string[] keys = new string[] { "mode","Score" };
var (status,response) = await rtmClient.GetPresence().RemoveStateAsync("Chat_room", RTM_CHANNEL_TYPE.MESSAGE, keys);
if (status.Error)
{
    Debug.Log(string.Format("{0} is failed!}", status.Operation));
    Debug.Log(string.Format("Error code : {0}", status.ErrorCode));
    Debug.Log(string.Format("Due to: {0}", status.Reason));
}
else
{
    Debug.Log("Remove State Success!");
}

Both the SetStateAsync and RemoveStateAsync methods trigger REMOTE_STATE_CHANGED event notifications. Users who join the channel with withPresence set to true receive event notifications containing full data of the user's temporary status.

Receive presence event notifications

A presence event notification returns the PresenceEvent data structure, which includes the RTM_PRESENCE_EVENT_TYPE parameter.

Event notification modes

The presence event notification mode determines how subscribed users receive event notifications. There are two notification modes:

Announce: Real-time notification mode
Interval: Scheduled notification mode

Real-time notification mode

{
      "type" : RTM_PRESENCE_EVENT_TYPE.REMOTE_JOIN,
      "channelTye" : RTM_CHANNEL_TYPE.MESSAGE,
      "channelName" : "Chat_room",
      "publisher" : "Tony",
}

{
      "type" : RTM_PRESENCE_EVENT_TYPE.REMOTE_LEAVE,
      "channelTye" : RTM_CHANNEL_TYPE.MESSAGE,
      "channelName" : "Chat_room",
      "publisher" : "Tony",
}

{
      "type" : RTM_PRESENCE_EVENT_TYPE.REMOTE_TIMEOUT,
      "channelTye" : RTM_CHANNEL_TYPE.MESSAGE,
      "channelName" : "Chat_room",
      "publisher" : "Tony",
}

{
      "type" : RTM_PRESENCE_EVENT_TYPE.REMOTE_STATE_CHANGED,
      "channelTye" : RTM_CHANNEL_TYPE.MESSAGE,
      "channelName" : "Chat_room",
      "publisher" : "Tony",
      "stateItems" : [{"Mic":"False"},{"Position":" Washington"}],
      "stateItemCount" : 2
}

Scheduled notification mode

{
      "type": "RTM_PRESENCE_EVENT_TYPE.INTERVAL",
      "channelType": "RTM_CHANNEL_TYPE.MESSAGE",
      "channelName": "Chat_room",
      "publisher": "Tony",
      "interval": {
          "joinUserList": ["Tony", "Lily"],
          "leaveUserList": ["Jason"],
          "timeoutUserList": ["Wendy"],
          "userStateList": [
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              },
              {
                  "userId": "Harvard",
                  "states": [
                      { "Mic": "False" },
                      { "Position": "Washington" }
                  ]
              }
          ]
      }
}

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

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