fix(datastore): full sync when sync predicate changes

aws-amplify · Feb 8, 2023 · ab127f7 · ab127f7
1 parent 74de7b9
commit ab127f7
Show file tree

Hide file tree

Showing 2 changed files with 33 additions and 3 deletions.
diff --git a/AmplifyPlugins/Core/AWSPluginsCore/Sync/ModelSync/ModelSyncMetadata.swift b/AmplifyPlugins/Core/AWSPluginsCore/Sync/ModelSync/ModelSyncMetadata.swift
@@ -13,10 +13,15 @@ public struct ModelSyncMetadata: Model {
 
     /// The timestamp (in Unix seconds) at which the last sync was started, as reported by the service
     public var lastSync: Int?
+
+    /// The sync predicate for this model, extracted out from the sync expression.
+    public var syncPredicate: String?
 
     public init(id: String,
-                lastSync: Int?) {
+                lastSync: Int?,
+                syncPredicate: String? = nil) {
         self.id = id
         self.lastSync = lastSync
+        self.syncPredicate = syncPredicate
     }
 }
diff --git a/...yPlugins/DataStore/Sources/AWSDataStorePlugin/Sync/InitialSync/InitialSyncOperation.swift b/...yPlugins/DataStore/Sources/AWSDataStorePlugin/Sync/InitialSync/InitialSyncOperation.swift
@@ -30,6 +30,10 @@ final class InitialSyncOperation: AsynchronousOperation {
         return dataStoreConfiguration.syncPageSize
     }
 
+    private var lastSyncPredicate: String?
+
+    private var currentSyncPredicate: String?
+
     private let initialSyncOperationTopic: PassthroughSubject<InitialSyncOperationEvent, DataStoreError>
     var publisher: AnyPublisher<InitialSyncOperationEvent, DataStoreError> {
         return initialSyncOperationTopic.eraseToAnyPublisher()
@@ -50,6 +54,8 @@ final class InitialSyncOperation: AsynchronousOperation {
 
         self.recordsReceived = 0
         self.initialSyncOperationTopic = PassthroughSubject<InitialSyncOperationEvent, DataStoreError>()
+        self.lastSyncPredicate = nil
+        self.currentSyncPredicate = nil
     }
 
     override func main() {
@@ -74,6 +80,7 @@ final class InitialSyncOperation: AsynchronousOperation {
         }
 
         let lastSyncMetadata = getLastSyncMetadata()
+        self.lastSyncPredicate = lastSyncMetadata?.syncPredicate
         guard let lastSync = lastSyncMetadata?.lastSync else {
             return nil
         }
@@ -125,7 +132,14 @@ final class InitialSyncOperation: AsynchronousOperation {
             $0.modelSchema.name == modelSchema.name
         }
         let queryPredicate = syncExpression?.modelPredicate()
-
+        // TODO: what is the correct way to store the predicate?
+        self.currentSyncPredicate = String(describing: queryPredicate)
+
+        var lastSyncTime = lastSyncTime
+        // Update `lastSyncTime` to perform a full sync if there is a change in sync predicate
+        if InitialSyncOperation.isDifferent(lastSyncPredicate, currentSyncPredicate) {
+            lastSyncTime = nil
+        }
         let completionListener: GraphQLOperation<SyncQueryResult>.ResultListener = { result in
             switch result {
             case .failure(let apiError):
@@ -154,6 +168,15 @@ final class InitialSyncOperation: AsynchronousOperation {
             api.query(request: nextRequest, listener: wrappedCompletionListener)
         }.main()
     }
+
+    private static func isDifferent(_ lastSyncPredicate: String?, _ currentSyncPredicate: String?) -> Bool {
+        guard let lastSyncPredicate = lastSyncPredicate,
+                let currentSyncPredicate = currentSyncPredicate else {
+            return false
+        }
+
+        return lastSyncPredicate != currentSyncPredicate
+    }
 
     /// Disposes of the query results: Stops if error, reconciles results if success, and kick off a new query if there
     /// is a next token
@@ -206,7 +229,9 @@ final class InitialSyncOperation: AsynchronousOperation {
             return
         }
 
-        let syncMetadata = ModelSyncMetadata(id: modelSchema.name, lastSync: lastSyncTime)
+        let syncMetadata = ModelSyncMetadata(id: modelSchema.name,
+                                             lastSync: lastSyncTime,
+                                             syncPredicate: currentSyncPredicate)
         storageAdapter.save(syncMetadata, condition: nil, eagerLoad: true) { result in
             switch result {
             case .failure(let dataStoreError):