Download files

The latest version of Amplify Storage supports specifying S3 objects as a paths.
We recommend using path instead of key to specify S3 objects.

Note: key parameter is deprecated and may be removed in next major version.

There are three ways of getting data that was previously uploaded:

Download data

You can download to in-memory buffer Data object with Amplify.Storage.downloadData:

With StoragePath

1let downloadTask = Amplify.Storage.downloadData(path: .fromString("public/example/path"))
2Task {
3    for await progress in await downloadTask.progress {
4        print("Progress: \(progress)")
5    }
6}
7let data = try await downloadTask.value
8print("Completed: \(data)")

1let downloadTask = Amplify.Storage.downloadData(path: .fromString("public/example/path"))
2let progressSink = downloadTask
3    .inProcessPublisher
4    .sink { progress in
5        print("Progress: \(progress)")
6    }
7
8let resultSink = downloadTask
9    .resultPublisher
10    .sink {
11        if case let .failure(storageError) = $0 {
12            print("Failed: \(storageError.errorDescription). \(storageError.recoverySuggestion)")
13        }
14    }
15    receiveValue: { data in
16        print("Completed: \(data)")
17    }

With Key (Deprecated)

1let downloadTask = Amplify.Storage.downloadData(key: "ExampleKey")
2Task {
3    for await progress in await downloadTask.progress {
4        print("Progress: \(progress)")
5    }
6}
7let data = try await downloadTask.value
8print("Completed: \(data)")

1let downloadTask = Amplify.Storage.downloadData(key: "ExampleKey")
2let progressSink = downloadTask
3    .inProcessPublisher
4    .sink { progress in
5        print("Progress: \(progress)")
6    }
7
8let resultSink = downloadTask
9    .resultPublisher
10    .sink {
11        if case let .failure(storageError) = $0 {
12            print("Failed: \(storageError.errorDescription). \(storageError.recoverySuggestion)")
13        }
14    }
15    receiveValue: { data in
16        print("Completed: \(data)")
17    }

Download to file

You can download to a file URL with Amplify.Storage.downloadFile:

With StoragePath

1let downloadToFileName = FileManager.default.urls(
2    for: .documentDirectory,
3    in: .userDomainMask
4)[0].appendingPathComponent("myFile.txt")
5
6let downloadTask = Amplify.Storage.downloadFile(
7    path: .fromString("public/example/path"),
8    local: downloadToFileName,
9    options: nil
10)
11Task {
12    for await progress in await downloadTask.progress {
13        print("Progress: \(progress)")
14    }
15}
16try await downloadTask.value
17print("Completed")

1let downloadToFileName = FileManager.default.urls(
2    for: .documentDirectory,
3    in: .userDomainMask
4)[0].appendingPathComponent("myFile.txt")
5
6let downloadTask = Amplify.Storage.downloadFile(
7    path: .fromString("public/example/path"),
8    local: downloadToFileName,
9    options: nil
10)
11let progressSink = downloadTask
12    .inProcessPublisher
13    .sink { progress in
14        print("Progress: \(progress)")
15    }
16
17let resultSink = downloadTask
18    .resultPublisher
19    .sink {
20        if case let .failure(storageError) = $0 {
21            print("Failed: \(storageError.errorDescription). \(storageError.recoverySuggestion)")
22        }
23    }
24    receiveValue: {
25        print("Completed")
26    }

With Key (Deprecated)

1let downloadToFileName = FileManager.default.urls(
2    for: .documentDirectory,
3    in: .userDomainMask
4)[0].appendingPathComponent("myFile.txt")
5
6let downloadTask = Amplify.Storage.downloadFile(
7    key: "myKey",
8    local: downloadToFileName,
9    options: nil
10)
11Task {
12    for await progress in await downloadTask.progress {
13        print("Progress: \(progress)")
14    }
15}
16try await downloadTask.value
17print("Completed")

1let downloadToFileName = FileManager.default.urls(
2    for: .documentDirectory,
3    in: .userDomainMask
4)[0].appendingPathComponent("myFile.txt")
5
6let downloadTask = Amplify.Storage.downloadFile(
7    key: "myKey",
8    local: downloadToFileName,
9    options: nil
10)
11let progressSink = downloadTask
12    .inProcessPublisher
13    .sink { progress in
14        print("Progress: \(progress)")
15    }
16
17let resultSink = downloadTask
18    .resultPublisher
19    .sink {
20        if case let .failure(storageError) = $0 {
21            print("Failed: \(storageError.errorDescription). \(storageError.recoverySuggestion)")
22        }
23    }
24    receiveValue: {
25        print("Completed")
26    }

Generate a download URL

You can also retrieve a URL for the object in storage:

1let url = try await Amplify.Storage.getURL(path: .fromString("public/example/path"))
2print("Completed: \(url)")

1let url = try await Amplify.Storage.getURL(key: "ExampleKey")
2print("Completed: \(url)")

When creating a downloadable URL, you can choose to check if the file exists by setting validateObjectExistence to true in AWSStorageGetURLOptions. If the file is inaccessible or does not exist, a StorageError is thrown. This allows you to check if an object exists during generating the presigned URL, which you can then use to download that object.

1let url = try await Amplify.Storage.getURL(
2    path: .fromString("public/example/path"),
3    options: .init(
4        pluginOptions: AWSStorageGetURLOptions(
5            validateObjectExistence: true
6        )
7    )
8)

1let url = try await Amplify.Storage.getURL(
2    key: "ExampleKey",
3    options: .init(
4        pluginOptions: AWSStorageGetURLOptions(
5            validateObjectExistence: true
6        )
7    )
8)

Cancel, Pause, Resume

Calls to downloadData or downloadFile return a reference to the task that is actually performing the download.

To cancel the download (for example, in response to the user pressing a Cancel button), you simply call cancel() on the download task.

1func cancelDownload() {
2    downloadTask.cancel()
3}

You can also pause and then resume the task.

1downloadTask.pause()
2downloadTask.resume()

Download tasks are run using URLSessionTask instances internally. You can learn more about them in Apple's official documentation.

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