Adding the Flexible Sync Configuration

Las thing we need to do is to pass this information to a new view, OpenSyncedRealmView, that will open the connection with our App and go through all the states needed while logging in our app.

Create OpenSyncedRealmView

Create a new SwiftUI view, add an app property. We'll need to add that argument to the preview call.

OpenSyncedRealmView

import SwiftUI
import RealmSwift

struct OpenSyncedRealmView: View {
    @ObservedObject var app: RealmSwift.App

    var body: some View {
        Text("Hello, World!")
    }
}

struct OpenSyncedRealmView_Previews: PreviewProvider {
    static var previews: some View {
        OpenSyncedRealmView(app: RealmSwift.App(id: ""))
    }
}

Using our config

We'll use our config in place of the default environment \.realmConfiguration.

SyncContentView.swift

// Remove this
//            Text("Logged in \(user)")

OpenSyncedRealmView(app: app)
                .environment(\.realmConfiguration, config)

Final listing for SyncContentView

SyncContentView.swift

import SwiftUI
import RealmSwift

struct SyncContentView: View {
    // Observe the Realm app object in order to react to login state changes.
    @ObservedObject var app: RealmSwift.App

    var body: some View {
        if let user = app.currentUser {
            // If there is a user logged in

            // Create a `flexibleSyncConfiguration` with `initialSubscriptions`.
            // We'll inject this configuration as an environment value to use when opening the realm
            // in the next view, and the realm will open with these initial subscriptions.
            let config = user.flexibleSyncConfiguration(initialSubscriptions: { subs in
            // Check whether the subscription already exists. Adding it more
            // than once causes an error.
            if let foundSubscriptions = subs.first(named: "user_days") {
                    // Existing subscription found - do nothing
                    return
            } else {
                    // Add queries for any objects you want to use in the app
                    // Linked objects do not automatically get queried, so you
                    // must explicitly query for all linked objects you want to include
                    subs.append(QuerySubscription<Days>(name: "user_days", query: {
                    // Query for objects where the ownerId is equal to the app's current user's id
                    // This means the app's current user can read and write their own data
                    $0.ownerId == user.id
                    }))
                    subs.append(QuerySubscription<Day>())
                    subs.append(QuerySubscription<Habits>(name: "user_habits", query: {
                    // Query for objects where the ownerId is equal to the app's current user's id
                    // This means the app's current user can read and write their own data
                    $0.ownerId == user.id
                    }))
                    subs.append(QuerySubscription<Habit>())
            }
            })

            OpenSyncedRealmView(app: app)
                .environment(\.realmConfiguration, config)
        } else {
            // If there is no user logged in, show the login view.
            ProgressView()
                .task{
                    do {
                        let myUser = try await app.login(credentials: .anonymous)
                    } catch {
                        print("\(error)")
                    }
                }
        }
    }
}

Log

If you look at the logs you'll see messages like

2023-07-05 17:59:39.708589+0200 GoodHabitsRealmApp[71190:9845203] Sync: Connection[1]: Session[1]: client_reset_config = false, Realm exists = true, client reset = false
2023-07-05 17:59:39.928362+0200 GoodHabitsRealmApp[71190:9845203] Sync: Connected to endpoint 'redacted-ip:443' (from 'my-ip:60529')
2023-07-05 17:59:41.038822+0200 GoodHabitsRealmApp[71190:9845203] Sync: Connection[1]: Connected to app services with request id: "64ah936ca2df64d089058fe9"
2023-07-05 17:59:41.648668+0200 GoodHabitsRealmApp[71190:9845203] Sync: Connection[1]: Session[1]: Begin processing pending FLX bootstrap for query version 0. (changesets: 1, original total changeset size: 0)