Enable passing custom URL sessions

CHANGELOG.md

@@ -9,6 +9,7 @@
 * Fix `SyncStatus.asFlow()` emitting the same object, causing SwiftUI to miss updates.
 * Add the `ObservableSyncStatus` utility, which can be used to track Sync Status updates through an `@Observable` class.
 * Clear `SyncStatus.uploadError` after a successful upload.
+* Allow passing a custom `URLSession` in `SyncClientConfiguration`.
 
 ## 1.14.4
 

Demos/PowerSyncExample/PowerSyncExample/PowerSync/SystemManager.swift

@@ -73,6 +73,12 @@ final class SystemManager {
 
     func connect() async {
         do {
+            // Passing a custom URL session is not required, but it can be used to intercept HTTP requests
+            // or to configure additional headers like shown here.
+            let config = URLSessionConfiguration.ephemeral
+            config.httpAdditionalHeaders = ["x-my-custom-header": "example"]
+            let session = URLSession(configuration: config)
+
             try await db.connect(
                 connector: connector,
                 options: ConnectOptions(
@@ -81,7 +87,8 @@ final class SystemManager {
                             requestLevel: .headers
                         ) { message in
                             self.db.logger.debug(message, tag: "SyncRequest")
-                        }
+                        },
+                        urlSession: session
                     )
                 )
             )

Sources/PowerSync/Implementation/PowerSyncDatabaseImpl.swift

@@ -6,7 +6,7 @@ final class PowerSyncDatabaseImpl: PowerSyncDatabaseProtocol {
     let group: ActiveDatabaseGroup
     let syncStatus = SwiftSyncStatus()
     private let dbFilename: String?
-    private let httpClient: HttpClient
+    private let customHttpClient: HttpClient?
     private let initializer = DatabaseInitializationAction()
     let pool: any SQLiteConnectionPoolProtocol
     let schema: AsyncMutex<Schema>
@@ -17,13 +17,13 @@ final class PowerSyncDatabaseImpl: PowerSyncDatabaseProtocol {
         activeInstanceStore: DatabaseGroupCollection = .shared,
         logger: any LoggerProtocol,
         pool: any SQLiteConnectionPoolProtocol,
-        httpClient: HttpClient,
+        customHttpClient: HttpClient?,
         schema: Schema
     ) {
         self.dbFilename = dbFilename
         self.logger = logger
         self.schema = AsyncMutex(schema)
-        self.httpClient = httpClient
+        self.customHttpClient = customHttpClient
         self.pool = pool
         self.group = activeInstanceStore.referenceGroup(identifier: identifier, logger: logger)
     }
@@ -133,7 +133,7 @@ final class PowerSyncDatabaseImpl: PowerSyncDatabaseProtocol {
 
     func connect(connector: any PowerSyncBackendConnectorProtocol, options: ConnectOptions?) async throws {
         try await initialize()
-        await group.syncCoordinator.connect(db: self, connector: connector, options: options ?? ConnectOptions(), client: httpClient)
+        await group.syncCoordinator.connect(db: self, connector: connector, options: options ?? ConnectOptions(), client: customHttpClient)
     }
 
     func disconnectAndClear(clearLocal: Bool, soft: Bool) async throws {

Sources/PowerSync/Implementation/sync/HttpClient.swift

@@ -79,8 +79,6 @@ struct PlatformHttpClient: HttpClient {
         let (data, response) = try await session.data(for: request)
         return (response as! HTTPURLResponse, data)
     }
-
-    static let shared = PlatformHttpClient(session: .shared)
 }
 
 /// A wrapper around a ``HttpClient`` emitting log events for responses and sync lines.

Sources/PowerSync/Implementation/sync/SyncCoordinator.swift

@@ -3,12 +3,17 @@ actor SyncCoordinator {
     nonisolated let streams = StreamTracker()
     private var activeSync: Task<Void, any Error>?
 
-    func connect(db: PowerSyncDatabaseImpl, connector: PowerSyncBackendConnectorProtocol, options: ConnectOptions, client: HttpClient) async {
+    func connect(db: PowerSyncDatabaseImpl, connector: PowerSyncBackendConnectorProtocol, options: ConnectOptions, client: HttpClient?) async {
         if let task = activeSync {
             await self.finishSyncTask(task: task)
         }
+
+        func defaultHttpClient() -> HttpClient {
+            let session = options.clientConfiguration?.urlSession ?? .shared
+            return PlatformHttpClient(session: session)
+        }
 
-        var client = client
+        var client = client ?? defaultHttpClient()
         if let logger = options.clientConfiguration?.requestLogger {
             client = LoggingClient(inner: client, logger: logger)
         }

Sources/PowerSync/PowerSyncDatabase.swift

@@ -36,7 +36,7 @@ public func PowerSyncDatabase(
         activeInstanceStore: group,
         logger: logger,
         pool: pool,
-        httpClient: PlatformHttpClient.shared,
+        customHttpClient: nil,
         schema: schema
     )
 }
@@ -66,7 +66,7 @@ public func OpenedPowerSyncDatabase(
         identifier: identifier,
         logger: logger,
         pool: pool,
-        httpClient: PlatformHttpClient.shared,
+        customHttpClient: nil,
         schema: schema
     )
 }

Sources/PowerSync/Protocol/PowerSyncDatabaseProtocol.swift

@@ -13,10 +13,21 @@ public struct SyncClientConfiguration: Sendable {
     /// - SeeAlso: `SyncRequestLoggerConfiguration` for configuration options
     public let requestLogger: SyncRequestLoggerConfiguration?
 
+    /// The URL session to use when connecting to the PowerSync service.
+    /// 
+    /// Customizing this may be convenient to add additional headers or to otherwise alter requests
+    /// sent by the PowerSync Swift SDK.
+    public var urlSession: URLSession
+
     /// Creates a new sync client configuration.
     /// - Parameter requestLogger: Optional network logger configuration
-    public init(requestLogger: SyncRequestLoggerConfiguration? = nil) {
+    /// - Parameter urlSession: Optional custom URL session to use for network requests.
+    public init(
+        requestLogger: SyncRequestLoggerConfiguration? = nil,
+        urlSession: URLSession = .shared,
+    ) {
         self.requestLogger = requestLogger
+        self.urlSession = urlSession
     }
 }
 
@@ -101,7 +112,7 @@ public struct ConnectOptions: Sendable {
         params: JsonParam = [:],
         clientConfiguration: SyncClientConfiguration? = nil,
         appMetadata: [String: String] = [:],
-        includeDefaultStreams: Bool = true
+        includeDefaultStreams: Bool = true,
     ) {
         self.crudThrottle = crudThrottle
         self.retryDelay = retryDelay

Tests/PowerSyncTests/Kotlin/ActiveInstanceStoreTests.swift

@@ -9,10 +9,10 @@ struct MultipleInstanceTest {
         let logger = DefaultLogger(minSeverity: .warning, writers: [logWriter])
         let schema = Schema()
 
-        let a = PowerSyncDatabaseImpl(identifier: "id", logger: logger, pool: pool, httpClient: PlatformHttpClient.shared, schema: schema)
+        let a = PowerSyncDatabaseImpl(identifier: "id", logger: logger, pool: pool, customHttpClient: nil, schema: schema)
         try #require(logWriter.getLogs().isEmpty)
 
-        let b = PowerSyncDatabaseImpl(identifier: "id", logger: logger, pool: pool, httpClient: PlatformHttpClient.shared, schema: schema)
+        let b = PowerSyncDatabaseImpl(identifier: "id", logger: logger, pool: pool, customHttpClient: nil, schema: schema)
         let _ = try #require(logWriter.getLogs().first { $0.contains("Multiple PowerSync instances for the same database have been detected.") })
 
         // Ensure databases are kept around until the end of the test (if a gets closed before, we would't see the warning).
@@ -27,10 +27,10 @@ struct MultipleInstanceTest {
         let schema = Schema()
 
         do {
-            let _ = PowerSyncDatabaseImpl(identifier: "id2", logger: logger, pool: pool, httpClient: PlatformHttpClient.shared, schema: schema)
+            let _ = PowerSyncDatabaseImpl(identifier: "id2", logger: logger, pool: pool, customHttpClient: nil, schema: schema)
         }
 
-        let b = PowerSyncDatabaseImpl(identifier: "id2", logger: logger, pool: pool, httpClient: PlatformHttpClient.shared, schema: schema)
+        let b = PowerSyncDatabaseImpl(identifier: "id2", logger: logger, pool: pool, customHttpClient: nil, schema: schema)
         try #require(logWriter.getLogs().isEmpty)
         let _ = consume b
     }

Tests/PowerSyncTests/Kotlin/SqlCursorTests.swift

@@ -70,7 +70,7 @@ final class SqlCursorTests: XCTestCase {
             activeInstanceStore: DatabaseGroupCollection(),
             logger: DefaultLogger(),
             pool: AsyncConnectionPool(location: .inMemory, logger: DefaultLogger()),
-            httpClient: PlatformHttpClient.shared,
+            customHttpClient: nil,
             schema: schema,
         )
         try await database.disconnectAndClear()

Tests/PowerSyncTests/SyncTests.swift

@@ -740,7 +740,7 @@ class InMemorySyncIntegrationTests {
     }
 
     @Test func subscriptionsUpdateWhileOffline() async throws {
-        let db = openDatabase(PlatformHttpClient.shared)
+        let db = openDatabase(PlatformHttpClient(session: .shared))
         // Make sure the database is initialized
         try await db.readLock { _ in }
         var statusUpdates = db.currentStatus.asFlow().makeAsyncIterator()
@@ -823,7 +823,7 @@ private func openDatabase(_ client: any HttpClient, schema: Schema = defaultSche
         activeInstanceStore: DatabaseGroupCollection(),
         logger: logger,
         pool: AsyncConnectionPool(location: .inMemory, logger: DefaultLogger()),
-        httpClient: client,
+        customHttpClient: client,
         schema: schema,
     )
 }