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Connect to an Atlas App Services Backend - Swift SDK

On this page

  • Access the App Client
  • Configuration
  • Sync Connection Sharing
  • Sync Timeout Options
  • Connect to a Specific Server
  • Connect to a Different Server During Runtime
  • Supported Operating Systems

The App client is the interface to the App Services backend. It provides access to the authentication functionality, functions, querying a MongoDB Atlas data source, and Device Sync.

Note

Apple Privacy Manifest

The SDK's Apple privacy manifest does not cover connecting to Atlas, or any usage of data through the App client. If your app connects to App Services, and you intend to distribute it through the Apple App Store, you may need to provide your own disclosures in your app's Apple privacy manifest.

For more information, refer to Apple Privacy Manifest.

Pass the App ID for your App, which you can find in the App Services UI.

let app = App(id: YOUR_APP_SERVICES_APP_ID) // replace YOUR_APP_SERVICES_APP_ID with your App ID

You can pass a configuration object to App:

let configuration = AppConfiguration(
baseURL: "https://services.cloud.mongodb.com", // You can customize base URL
transport: nil, // Custom RLMNetworkTransportProtocol
defaultRequestTimeoutMS: 30000
)
let app = App(id: "my-app-services-app-id", configuration: configuration)

You can create multiple App client instances to connect to multiple Apps. All App client instances that share the same App ID use the same underlying connection.

Important

Changing an App Config After Initializing the App

Starting with Swift SDK version 10.46.0, you can change a baseURL in the App config and the App client uses the new baseURL. In Swift SDK versions 10.45.3 and earlier, when you initialize the App client, the configuration is cached internally. Attempting to close an App and then re-open it with a changed configuration within the same process has no effect. The client continues to use the cached configuration.

New in version 10.41.0.

You can set the enableSessionMultiplexing bool on the AppConfiguration to specify whether the Realm Swift SDK should open a connection to the server for each synced realm, or share a connection to the server for all synced realms.

If you do not specify a value for this bool, Realm defaults to sharing a single connection per App Services user for all synced realms.

let configuration = AppConfiguration(enableSessionMultiplexing: false)
let app = App(id: YOUR_APP_SERVICES_APP_ID, configuration: configuration)

New in version 10.41.0.

You can set various sync timeout options on the AppConfiguration. The syncTimeouts property can accept a SyncTimeoutOptions object to override default values for these settings.

For a complete list of the available timeout settings and their definitions, refer to RLMSyncTimeoutOptions.

let syncTimeoutOptions = SyncTimeoutOptions(
connectTimeout: 30000,
connectionLingerTime: 5000,
pingKeepalivePeriod: 10000,
pongKeepaliveTimeout: 10000,
fastReconnectLimit: 30000
)
let configuration = AppConfiguration(syncTimeouts: syncTimeoutOptions)
let app = App(id: YOUR_APP_SERVICES_APP_ID, configuration: configuration)

By default, Atlas Device SDK connects to Atlas using the global baseURL of https://services.cloud.mongodb.com. In some cases, you may want to connect to a different server:

  • Your App Services App uses local deployment, and you want to connect directly to a local baseURL in your region.

  • You want to connect to an Edge Server instance.

You can specify a baseURL in the AppConfiguration:

// Specify a baseURL to connect to a server other than the default.
// In this case, an Edge Server instance running on the device.
let configuration = AppConfiguration(baseURL: "http://localhost:80")
let edgeApp = App(id: EDGE_SERVER_APP_ID, configuration: configuration)

New in version 10.50.0.

In some cases, you might want to change the baseURL while the app is running. For example, you might want to roam between Edge Servers, or move from an App Services connection to an Edge Server connection. To change the baseURL during runtime, call the app.updateBaseUrl(to: ) method:

// Specify a baseURL to connect to a server other than the default.
// In this case, an Edge Server instance running on the device.
let configuration = AppConfiguration(baseURL: "http://localhost:80")
let edgeApp = App(id: EDGE_SERVER_APP_ID, configuration: configuration)
// You can check the `baseURL` of an app to define app logic.
if edgeApp.baseURL == "http://localhost:80" {
print("Client app is currently connected to a local Edge Server instance")
}
// ... log in a user and use the app...
// ... some time later...
try await edgeApp.updateBaseUrl(to: "https://services.cloud.mongodb.com")

This API is experimental, so you must use the experimental import in the file where you want to use this API:

@_spi(RealmSwiftExperimental) import RealmSwift

If you want to change the baseURL after you have logged in a user and have opened a synced database, the app must perform a client reset. Perform these steps in your code:

  1. Pause the Sync session.

  2. Update the baseURL by calling the app.updateBaseUrl(to: ) method.

  3. Authenticate and log the user in again with the new baseURL.

  4. Open a synced database pulling data from the new server.

Both the server and the client must be online for the user to authenticate and connect to the new server. If the server is not online or the client does not have a network connection, the user cannot authenticate and open the database.

The Realm Swift SDK supports connecting to an Atlas App Services App for a range of Apple operating systems depending on the Xcode version and Realm Swift SDK version. Connecting to an App Services App enables:

  • Authentication and User Management

  • Calling an Atlas Function

  • Querying a MongoDB Atlas Data Source

  • Device Sync

For current information about supported operating systems, refer to OS Support.

At this time, the Realm Swift SDK does not support connecting to an App Services App from watchOS.

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