Realtime

Realtime allows you to listen to any events on the server-side in realtime using the subscribe method.

Instead of requesting new data via HTTP, the subscription will receive new data every time it changes, any connected client receives that update within milliseconds via a WebSocket connection.

This lets you build an interactive and responsive user experience by providing information from all of Appwrite's services in realtime. The example below shows subscribing to realtime events for file uploads.

• Web

  const sdk = new Appwrite();
  
  sdk
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1') // Your API Endpoint
      .setProject('5df5acd0d48c2') // Your project ID
  ;
  
  // Subscribe to files channel
  sdk.subscribe('files', response => {
      if(response.event === 'storage.files.create') {
          // Log when a new file is uploaded
          console.log(response.payload);
      }
  });

• Flutter

  final client = Client();
  
  client
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1') // Your Appwrite Endpoint
      .setProject('5e8cf4f46b5e8') // Your project ID
  ;
  
  final realtime = Realtime(client);
  
  // Subscribe to files channel
  final subscription = realtime.subscribe(['files']);
  
  subscription.stream.listen((response) {
      if(response.event == 'storage.files.create') {
      // Log when a new file is uploaded
      print(response.payload);
      }
  });

• Android

  val client = Client(context)
  
  client
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1") // Your API Endpoint
      .setProject("5df5acd0d48c2") // Your project ID
  
  val realtime = Realtime(client)
  
  // Subscribe to files channel
  realtime.subscribe("files", callback = { response ->
      if(response.event === "storage.files.create") {
          // Log when a new file is uploaded
          print(response.payload.toString());
      }
  })

• Apple

  let client = Client()
  
  client
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1") // Your API Endpoint
      .setProject("5df5acd0d48c2") // Your project ID
  
  let realtime = Realtime(client: client)
  
  // Subscribe to files channel
  let subscription = realtime.subscribe(channels: ["files"]) { message in
      if(message.event == "storage.files.create") {
          // Log when a new file is uploaded
          print(String(describing: message.payload))
      }
  }

To subscribe to updates from different resources, you need to specify one or more channels. The channels offer a wide and powerful selection that will allow you to listen to all possible resources. This allows you to receive updates not only from the database, but from all the services that Appwrite offers.

If you listen to all documents from a collection by subscribing to the collections.[ID].documents channel, you can use the event attribute in the callback to distinguish whether a new document was created or an existing one was updated.

All possible events can be found here.

Examples

The examples below will show you how you can use Realtime in various ways.

Subscribe to a Channel

In this example we are subscribing to all updates related to our account by using the account channel. This will be triggered by any update related to the authenticated user, like updating the user's name or e-mail address.

• Web

  const sdk = new Appwrite();
  
  sdk.subscribe('account', response => {
      // Callback will be executed on all account events.
      console.log(response);
  });

• Flutter

  final client = Client();
  final realtime = Realtime(client);
  final subscription = realtime.subscribe(['account']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on all account events.
      print(response);
  })

• Android

  val client = Client(context)
  val realtime = Realtime(client)
  
  realtime.subscribe("account", callback = { param ->
      // Callback will be executed on all account events.
      print(param.toString())
  })

• Apple

  let client = Client()
  let realtime = Realtime(client)
  
  realtime.subscribe(channel: "account", callback: { param in
      // Callback will be executed on all account events.
      print(String(describing: param))
  })

Subscribe to Multiple Channels

You can also listen to multiple channels at once by passing an array of channels. This will trigger the callback for any events for all channels passed.

In this example we are listening to the document A and all files by subscribing to the collections.A.documents.A and files channels.

• Web

  const sdk = new Appwrite();
  
  sdk.subscribe(['collections.A.documents.A', 'files'], response => {
      // Callback will be executed on changes for documents A and all files.
      console.log(response);
  });

• Flutter

  final client = Client();
  final realtime = Realtime(client);
  final subscription = realtime.subscribe(['collections.A.documents.A', 'files']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on changes for documents A and all files.
      print(response);
  })

• Android

  val client = Client(context)
  val realtime = Realtime(client)
  
  realtime.subscribe("collections.A.documents.A", "files", callback = { param ->
      // Callback will be executed on changes for documents A and all files.
      print(param.toString())
  })

• Apple

  let client = Client()
  let realtime = Realtime(client)
  
  realtime.subscribe(channels: ["collections.A.documents.A", "files"], callback: { param in
      // Callback will be executed on changes for documents A and all files.
      print(String(describing: param))
  })

Unsubscribe

If you no longer want to receive updates from a subscription, you can unsubscribe so that your callbacks are no longer called.

• Web

  const sdk = new Appwrite();
  
  const unsubscribe = sdk.subscribe('files', response => {
      // Callback will be executed on changes for all files.
      console.log(response);
  });
  
  // Closes the subscription.
  unsubscribe();

• Flutter

  final client = Client();
  final realtime = Realtime(client);
  final subscription = realtime.subscribe(['files']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on changes for all files.
      print(response);
  })
  
  // Closes the subscription.
  subscription.close();

• Android

  val client = Client(context)
  val realtime = Realtime(client)
  
  val subscription = realtime.subscribe("files", callback = { param ->
      // Callback will be executed on changes for all files.
      print(param.toString())
  })
  
  // Closes the subscription.
  subscription.close()

• Apple

  let client = Client()
  let realtime = Realtime(client)
  
  let subscription = realtime.subscribe(channel: "files", callback: { param in
      // Callback will be executed on changes for all files.
      print(param.toString())
  })
  
  // Closes the subscription.
  subscription.close()

Payload

The payload from the subscription will contain following properties:

If you subscribe to the documents channel and a document the user is allowed to read is updated, you will receive an object containing information about the event and the updated document.

The response will look like this:

{
    "event": "database.documents.update",
    "channels": [
        "documents",
        "documents.[DOCUMENT_ID]",
        "collections.[COLLECTION_ID].documents"
    ],
    "timestamp": 1629719169,
    "payload": {
        "$id": "[DOCUMENT_ID]",
        "$collection": "[COLLECTION_ID]",
        "$permissions": [],
        "attribute1": "lorem",
        "attribute2": 2030
    }
}

Channels

A list of all channels available you can subscribe to:

Custom Endpoint

The SDK will guess the endpoint of the Realtime API when setting the endpoint of your Appwrite instance. If you are running Appwrite with a custom proxy and changed the route of the Realtime API, you can call the setEndpointRealtime method on the Client SDK and set your new endpoint value.

By default the endpoint is wss://[HOSTNAME_OR_IP]/v1/realtime.

• Web

  const sdk = new Appwrite();
  
  sdk.setEndpointRealtime('[HOSTNAME_OR_IP]');

• Flutter

  final client = Client();
  client.setEndpointRealtime('[HOSTNAME_OR_IP]');

• Android

  val client = Client(context)
  client.setEndpointRealtime("[HOSTNAME_OR_IP]")

• Apple

  let client = Client()
  client.setEndpointRealtime("[HOSTNAME_OR_IP]")

Known Limitations

Authentication with Existing Subscription

If you authenticate a user and have an already existing subscription, the subscription will not receive updates for the newly authenticated user. You would need to re-create the subscription so that it will work with the new user.

Rapid Subscriptions Changes

The SDK creates a single WebSocket connection for all subscribed channels. Each time a channel is added or unsubscribed - the SDK currently creates a completely new connection and terminates the old one. Therefore, subscriptions to channels should always be done in conjunction with state management so as not to be unnecessarily built up several times by multiple components' life cycles.

Nested Documents

Nested Documents will not trigger events related to their parent documents. Meaning, updates to a child document - will not trigger an event for the parent document. But it will trigger an event for the child document itself.

Server-Side?

We currently are not offering access to realtime with Server SDKs and an API key.