Realtime Store - Flutter

The Realtime Store allows you to store, update, retrieve, and observe custom key-value data within a meeting — in real time. It acts as a shared data layer across all connected participants, ensuring synchronized states throughout the session.

This is particularly useful for collaborative or stateful meeting experiences such as:

• Pinned messages and flags
• Moderation data (e.g., blocked users)
• Collaborative notes or polls

setValue()

The setValue() method is used to store or update data in the RealtimeStore. If a key already exists, it will be overwritten with the new value. Passing null as the value deletes the key.

Key Notes

• Supports String values only.
• Each key can store up to 1 KB of data.
• A maximum of 100 keys are allowed per session.
• Deletion is performed by setting the value to null.
• Throws an error if:
  • The key is missing or empty.
  • The request fails.
  • The session exceeds the 100-key limit.

Parameters

• key (String)
  The unique key to store the data under.

• value (String?)
  The string value to be stored. Pass null to delete the key.

Example

import 'package:flutter/material.dart';
import 'package:videosdk/videosdk.dart';

class MeetingScreen extends StatefulWidget {
  //Existing configuration
}

class _MeetingScreenState extends State<MeetingScreen> {
  late Room _room;

  @override
  void initState() {
    _room = VideoSDK.createRoom(
      roomId: widget.meetingId,
      token: widget.token,
      displayName: "User1",
      micEnabled: true,
      camEnabled: true,
      defaultCameraIndex: 0,
      multiStream: true,
      mode: Mode.SEND_AND_RECV,
    );
    _room.join();
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: [
      ElevatedButton(
        String key = "BLOCK_CHAT";
        String value = "true";
        onPressed: () async {
            try {
              await _room.realtimeStore.setValue(key, value);
            } catch(e){
              print("Error:$e");
            }
        },
        child: const Text("Realtime Store Set Value"),
      ),
    ]);
  }
}

---

getValue()

The getValue() method retrieves the current value associated with a given key.

Key Notes

• Returns the current string value for the given key.
• Useful for fetching shared state when joining a meeting or reloading a view.
• Throws an error if the key is missing/empty or if the request fails.

Parameters

• key (String)
  The key whose value you want to retrieve.

Example

import 'package:flutter/material.dart';
import 'package:videosdk/videosdk.dart';

class MeetingScreen extends StatefulWidget {
  //Existing configuration
}

class _MeetingScreenState extends State<MeetingScreen> {
  late Room _room;

  @override
  void initState() {
    _room = VideoSDK.createRoom(
      roomId: widget.meetingId,
      token: widget.token,
      displayName: "User1",
      micEnabled: true,
      camEnabled: true,
      defaultCameraIndex: 0,
      multiStream: true,
      mode: Mode.SEND_AND_RECV,
    );
    _room.join();
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: [
       ElevatedButton(
        String key = "BLOCK_CHAT";
        String response= "";
        onPressed: () async {
          try { 
            response = await _room.realtimeStore.getValue(key);
          } catch(e){
            print("Error:$e");
          }
        },
        child: const Text("Realtime Store Get Value:$response"),
      ),
    ]);
  }
}

---

observe()

The observe() method subscribes to real-time updates for a given key. When the key’s value changes, a delegate method on your listener is automatically triggered for all connected participants.

Key Notes

• Returns an observerId which you can later use to stop observing.
• The callback receives the new value and information about who updated it.
• Ideal for syncing live data like timers, shared notes, or agendas.

Parameters

• key (String)
  The key to observe.

• callback (function) Function triggered on each update. Receives:

  • value (String?) → Updated value or null if deleted
  • updatedBy (Participant?) → Object of participant who made the update

Example

import 'package:flutter/material.dart';
import 'package:videosdk/videosdk.dart';

class MeetingScreen extends StatefulWidget {
  //Existing configuration
}

class _MeetingScreenState extends State<MeetingScreen> {
  late Room _room;

  @override
  void initState() {
    _room = VideoSDK.createRoom(
      roomId: widget.meetingId,
      token: widget.token,
      displayName: "User1",
      micEnabled: true,
      camEnabled: true,
      defaultCameraIndex: 0,
      multiStream: true,
      mode: Mode.SEND_AND_RECV,
    );
    _room.join();
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: [
       ElevatedButton(
        String key = "BLOCK_CHAT";
          onPressed: () async {
         try {
            observerId = await meeting.realtimeStore.observe(key,(value, updatedBy) {
              print("Updated by: ${updatedBy!.id}");
            },
        );
        } catch(e){
          print("Error:$e");
        }
       }
      child: const Text("Realtime Store Observe"),
      ),
    ]);
  } 
}

---

stopObserving()

Stops receiving updates for a specific key and listener combination.

Key Notes

• Should be called when the listener is no longer needed (e.g., component unmount).

Parameters

• observerId (String) The observer ID returned from observe().

Example

import 'package:flutter/material.dart';
import 'package:videosdk/videosdk.dart';

class MeetingScreen extends StatefulWidget {
  //Existing configuration
}

class _MeetingScreenState extends State<MeetingScreen> {
  late Room _room;

  @override
  void initState() {
    _room = VideoSDK.createRoom(
      roomId: widget.meetingId,
      token: widget.token,
      displayName: "User1",
      micEnabled: true,
      camEnabled: true,
      defaultCameraIndex: 0,
      multiStream: true,
      mode: Mode.SEND_AND_RECV,
    );
    _room.join();
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: [
       ElevatedButton(
         onPressed: () async {
          try{
          if (observerId != null) {
            await meeting.realtimeStore
                .stopObserving(observerId!);
            print(
                "Stopped observing with ID: $observerId");
            observerId = null; // Clear the observer ID
          } else {
            print("No active observer to stop");
          }
          } catch(e){
            print("Error:$e");
          }
          Navigator.pop(context);
        },        
      ),
    ]);
  }
}

---

Error Handling & Constraints

Property	Description
Error Handling	All errors will be handled in onError() callback.
Payload Size	Maximum 1 KB per key.
Supported Type	Only String values are supported. Use null to delete key.
Concurrency	The latest write overwrites previous values (last write wins)
Key Limit	A maximum of 100 keys are allowed in a single session.

API Reference

The API references for this page are provided below.

• setValue()
• getValue()
• observe()
• stopObserving()