Setting the file. One moment.
Subchapter 130.13
references/storage-mobile.mdMarkdown10 KBView on GitHub
Initialize Amplify with Auth and Storage plugins before using this feature:
Flutter — lib/main.dart:
await Amplify.addPlugins([AmplifyAuthCognito(), AmplifyStorageS3()]);
await Amplify.configure(amplifyConfig);Generate dart outputs:
npx ampx sandbox --outputs-format dart --outputs-out-dir lib
Swift (Apple platforms):
try Amplify.add(plugin: AWSCognitoAuthPlugin())
try Amplify.add(plugin: AWSS3StoragePlugin())
try Amplify.configure(with: .amplifyOutputs)Drag
amplify_outputs.jsoninto the Xcode project navigator so it is included in the app bundle.
Android:
Amplify.addPlugin(AWSCognitoAuthPlugin())
Amplify.addPlugin(AWSS3StoragePlugin())
Amplify.configure(AmplifyOutputs(R.raw.amplify_outputs), applicationContext)Place
amplify_outputs.jsoninapp/src/main/res/raw/. Enable core library desugaring for API level < 26.Backend required: Storage must be defined in
amplify/storage/resource.tsusingdefineStorage— see storage-backend.md.
Imports: amplify_flutter + amplify_storage_s3. All paths wrapped with StoragePath.fromString().
| Operation | Call |
|---|---|
| Upload file | Amplify.Storage.uploadFile(localFile: AWSFile.fromPath(path), path: const StoragePath.fromString('public/photo.jpg')) |
| Download file | Amplify.Storage.downloadFile(path: const StoragePath.fromString('public/photo.jpg'), localFile: localFile) |
| List | Amplify.Storage.list(path: const StoragePath.fromString('public/')) → .result.items |
| Presigned URL | Amplify.Storage.getUrl(path: const StoragePath.fromString('public/file.jpg')) |
| Remove | Amplify.Storage.remove(path: const StoragePath.fromString('public/file.jpg')) |
Security: Amplify Gen2 enables S3 server-side encryption (SSE-S3) by default. All transfers use HTTPS (TLS in transit). For sensitive data, configure SSE-KMS with a customer-managed key via CDK overrides.
Upload progress — use the onProgress callback parameter:
final op = Amplify.Storage.uploadFile(
localFile: AWSFile.fromPath('/path/to/file'),
path: const StoragePath.fromString('public/photos/photo.jpg'),
onProgress: (p) => print('fraction: ${p.fractionCompleted}'),
);
final result = await op.result;Use const with StoragePath.fromString() for compile-time constant paths.
Supported: iOS 13+, macOS 12+, tvOS 13+, watchOS 9+, visionOS 1+ (preview).
Uses Amplify.Storage with async/await. Import: Amplify.
| Operation | Call |
|---|---|
| Upload data | Amplify.Storage.uploadData(path: .fromString("public/file.txt"), data: data) → try await task.value |
| Upload file | Amplify.Storage.uploadFile(path: .fromString("public/file.txt"), local: fileUrl) → try await task.value |
| Download data | Amplify.Storage.downloadData(path: .fromString("public/file.txt")) → .value returns Data |
| Download file | Amplify.Storage.downloadFile(path: .fromString("public/path"), local: fileUrl) → try await task.value |
| List | try await Amplify.Storage.list(path: .fromString("public/")) → .items |
| Presigned URL | try await Amplify.Storage.getURL(path: .fromString("public/file.jpg")) |
| Remove | try await Amplify.Storage.remove(path: .fromString("public/file.jpg")) |
Download with progress tracking:
let downloadTask = Amplify.Storage.downloadData(
path: .fromString("public/example.jpg")
)
Task {
for await progress in await downloadTask.progress {
print("Progress: \(progress.fractionCompleted)")
}
}
let data = try await downloadTask.valueUpload with progress tracking:
let uploadTask = Amplify.Storage.uploadData(
path: .fromString("public/photo.jpg"),
data: imageData
)
Task {
for await progress in await uploadTask.progress {
print("Progress: \(progress)")
}
}
let result = try await uploadTask.valueUse SwiftUI’s PhotosPicker (from import PhotosUI) to obtain image data,
then pass to uploadData.
Android supports both callback-based and coroutine-based APIs.
Import: com.amplifyframework.core.Amplify, com.amplifyframework.storage.StoragePath.
Coroutine example (recommended):
private suspend fun uploadFile() {
val exampleFile = File(applicationContext.filesDir, "example")
exampleFile.writeText("Example file contents")
val upload = Amplify.Storage.uploadFile(
StoragePath.fromString("public/example"), exampleFile
)
try {
val result = upload.result()
Log.i("MyAmplifyApp", "Successfully uploaded: ${result.path}")
} catch (error: StorageException) {
Log.e("MyAmplifyApp", "Upload failed", error)
}
}private suspend fun downloadFile() {
val download = Amplify.Storage.downloadFile(
StoragePath.fromString("public/example"), localFile
)
try {
val result = download.result()
Log.i("MyAmplifyApp", "Successfully downloaded: ${result.file.name}")
} catch (error: StorageException) {
Log.e("MyAmplifyApp", "Download failed", error)
}
}| Operation (coroutine) | Call |
|---|---|
| Upload file | Amplify.Storage.uploadFile(StoragePath.fromString("public/photo.jpg"), file) → .result() |
| Upload stream | Amplify.Storage.uploadInputStream(StoragePath.fromString("public/example"), stream) → .result() |
| Download file | Amplify.Storage.downloadFile(StoragePath.fromString("public/photo.jpg"), localFile) → .result() |
| List | Amplify.Storage.list(StoragePath.fromString("public/")) → .items |
| Presigned URL | Amplify.Storage.getUrl(StoragePath.fromString("public/file.jpg")) → .url |
| Remove | Amplify.Storage.remove(StoragePath.fromString("public/file.jpg")) |
Callback alternative: all operations also accept onSuccess/onError lambdas — e.g.
Amplify.Storage.uploadFile(StoragePath.fromString("public/photo.jpg"), file, { result -> ... }, { error -> ... }).
For authenticated user paths, use protected/{entity_id}/ or private/{entity_id}/ — the {entity_id} resolves to the user’s Cognito identity ID at runtime.
INTERNET permission is declared in AndroidManifest.xml (usually present by default). If the app accesses the camera, add CAMERA; for gallery access, add READ_MEDIA_IMAGES (API 33+) or READ_EXTERNAL_STORAGE (older).NSCameraUsageDescription in Info.plist. If the app accesses the photo library, add NSPhotoLibraryUsageDescription.AndroidManifest.xml and Info.plist respectively.getURL (capital URL), not getUrl: Using the
wrong casing (lowercase l) causes compile errors. JS/web uses
getUrl (lowercase), but Swift uses getURL.AWSFile.fromPath(), Swift uses Data (for uploadData) or a file
URL (for uploadFile), Android uses File. Using the wrong type
causes compile errors — check the platform’s expected input.StoragePath.fromString(): Flutter and Android require
StoragePath.fromString('path') to wrap path strings. Passing a raw
string literal does not compile.onProgress in Flutter, for await progress in ...
in Swift, transferObserver or progress callback in Android) to show
upload progress to the user.