Amazon S3 examples using SDK for Swift

The following code examples show you how to perform actions and implement common scenarios by using the AWS SDK for Swift with Amazon S3.

Basics are code examples that show you how to perform the essential operations within a service.

Actions are code excerpts from larger programs and must be run in context. While actions show you how to call individual service functions, you can see actions in context in their related scenarios.

Each example includes a link to the complete source code, where you can find instructions on how to set up and run the code in context.

Basics

Learn the basics

The following code example shows how to:

• Create a bucket and upload a file to it.

• Download an object from a bucket.

• Copy an object to a subfolder in a bucket.

• List the objects in a bucket.

• Delete the bucket objects and the bucket.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

A Swift class that handles calls to the SDK for Swift.

import Foundation
import AWSS3
import ClientRuntime
import AWSClientRuntime
import Smithy

/// A class containing all the code that interacts with the AWS SDK for Swift.
public class ServiceHandler {
    let client: S3Client
    
    /// Initialize and return a new ``ServiceHandler`` object, which is used to drive the AWS calls
    /// used for the example.
    ///
    /// - Returns: A new ``ServiceHandler`` object, ready to be called to
    ///            execute AWS operations.
    public init() async {
        do {
            client = try S3Client(region: "us-east-2")
        } catch {
            print("ERROR: ", dump(error, name: "Initializing S3 client"))
            exit(1)
        }
    }

    /// Create a new user given the specified name.
    ///
    /// - Parameters:
    ///   - name: Name of the bucket to create.
    /// Throws an exception if an error occurs.
    public func createBucket(name: String) async throws {
        let config = S3ClientTypes.CreateBucketConfiguration(
            locationConstraint: .usEast2
        )
        let input = CreateBucketInput(
            bucket: name,
            createBucketConfiguration: config
        )
        _ = try await client.createBucket(input: input)
    }

    /// Delete a bucket.
    /// - Parameter name: Name of the bucket to delete.
    public func deleteBucket(name: String) async throws {
        let input = DeleteBucketInput(
            bucket: name
        )
        _ = try await client.deleteBucket(input: input)
    }

    /// Upload a file from local storage to the bucket.
    /// - Parameters:
    ///   - bucket: Name of the bucket to upload the file to.
    ///   - key: Name of the file to create.
    ///   - file: Path name of the file to upload.
    public func uploadFile(bucket: String, key: String, file: String) async throws {
        let fileUrl = URL(fileURLWithPath: file)
        let fileData = try Data(contentsOf: fileUrl)
        let dataStream = ByteStream.data(fileData)

        let input = PutObjectInput(
            body: dataStream,
            bucket: bucket,
            key: key
        )
        _ = try await client.putObject(input: input)
    }

    /// Create a file in the specified bucket with the given name. The new
    /// file's contents are uploaded from a `Data` object.
    ///
    /// - Parameters:
    ///   - bucket: Name of the bucket to create a file in.
    ///   - key: Name of the file to create.
    ///   - data: A `Data` object to write into the new file.
    public func createFile(bucket: String, key: String, withData data: Data) async throws {
        let dataStream = ByteStream.data(data)

        let input = PutObjectInput(
            body: dataStream,
            bucket: bucket,
            key: key
        )
        _ = try await client.putObject(input: input)
    }

    /// Download the named file to the given directory on the local device.
    ///
    /// - Parameters:
    ///   - bucket: Name of the bucket that contains the file to be copied.
    ///   - key: The name of the file to copy from the bucket.
    ///   - to: The path of the directory on the local device where you want to
    ///     download the file.
    public func downloadFile(bucket: String, key: String, to: String) async throws {
        let fileUrl = URL(fileURLWithPath: to).appendingPathComponent(key)

        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        let output = try await client.getObject(input: input)

        // Get the data stream object. Return immediately if there isn't one.
        guard let body = output.body,
              let data = try await body.readData() else {
            return
        }
        try data.write(to: fileUrl)
    }

    /// Read the specified file from the given S3 bucket into a Swift
    /// `Data` object.
    ///
    /// - Parameters:
    ///   - bucket: Name of the bucket containing the file to read.
    ///   - key: Name of the file within the bucket to read.
    ///
    /// - Returns: A `Data` object containing the complete file data.
    public func readFile(bucket: String, key: String) async throws -> Data {
        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        let output = try await client.getObject(input: input)

        // Get the stream and return its contents in a `Data` object. If
        // there is no stream, return an empty `Data` object instead.
        guard let body = output.body,
              let data = try await body.readData() else {
            return "".data(using: .utf8)!
        }
        
        return data
    }

    /// Copy a file from one bucket to another.
    ///
    /// - Parameters:
    ///   - sourceBucket: Name of the bucket containing the source file.
    ///   - name: Name of the source file.
    ///   - destBucket: Name of the bucket to copy the file into.
    public func copyFile(from sourceBucket: String, name: String, to destBucket: String) async throws {
        let srcUrl = ("\(sourceBucket)/\(name)").addingPercentEncoding(withAllowedCharacters: .urlPathAllowed)

        let input = CopyObjectInput(
            bucket: destBucket,
            copySource: srcUrl,
            key: name
        )
        _ = try await client.copyObject(input: input)
    }

    /// Deletes the specified file from Amazon S3.
    ///
    /// - Parameters:
    ///   - bucket: Name of the bucket containing the file to delete.
    ///   - key: Name of the file to delete.
    ///
    public func deleteFile(bucket: String, key: String) async throws {
        let input = DeleteObjectInput(
            bucket: bucket,
            key: key
        )

        do {
            _ = try await client.deleteObject(input: input)
        } catch {
            throw error
        }
    }

    /// Returns an array of strings, each naming one file in the
    /// specified bucket.
    ///
    /// - Parameter bucket: Name of the bucket to get a file listing for.
    /// - Returns: An array of `String` objects, each giving the name of
    ///            one file contained in the bucket.
    public func listBucketFiles(bucket: String) async throws -> [String] {
        let input = ListObjectsV2Input(
            bucket: bucket
        )
        let output = try await client.listObjectsV2(input: input)
        var names: [String] = []

        guard let objList = output.contents else {
            return []
        }

        for obj in objList {
            if let objName = obj.key {
                names.append(objName)
            }
        }

        return names
    }
}

A Swift command-line program to manage the SDK calls.

import Foundation
import ServiceHandler
import ArgumentParser

/// The command-line arguments and options available for this
/// example command.
struct ExampleCommand: ParsableCommand {
    @Argument(help: "Name of the S3 bucket to create")
    var bucketName: String

    @Argument(help: "Pathname of the file to upload to the S3 bucket")
    var uploadSource: String

    @Argument(help: "The name (key) to give the file in the S3 bucket")
    var objName: String

    @Argument(help: "S3 bucket to copy the object to")
    var destBucket: String

    @Argument(help: "Directory where you want to download the file from the S3 bucket")
    var downloadDir: String

    static var configuration = CommandConfiguration(
        commandName: "s3-basics",
        abstract: "Demonstrates a series of basic AWS S3 functions.",
        discussion: """
        Performs the following Amazon S3 commands:

        * `CreateBucket`
        * `PutObject`
        * `GetObject`
        * `CopyObject`
        * `ListObjects`
        * `DeleteObjects`
        * `DeleteBucket`
        """
    )

    /// Called by ``main()`` to do the actual running of the AWS
    /// example.
    func runAsync() async throws {
        let serviceHandler = await ServiceHandler()

        // 1. Create the bucket.
        print("Creating the bucket \(bucketName)...")
        try await serviceHandler.createBucket(name: bucketName)

        // 2. Upload a file to the bucket.
        print("Uploading the file \(uploadSource)...")
        try await serviceHandler.uploadFile(bucket: bucketName, key: objName, file: uploadSource)

        // 3. Download the file.
        print("Downloading the file \(objName) to \(downloadDir)...")
        try await serviceHandler.downloadFile(bucket: bucketName, key: objName, to: downloadDir)

        // 4. Copy the file to another bucket.
        print("Copying the file to the bucket \(destBucket)...")
        try await serviceHandler.copyFile(from: bucketName, name: objName, to: destBucket)

        // 5. List the contents of the bucket.

        print("Getting a list of the files in the bucket \(bucketName)")
        let fileList = try await serviceHandler.listBucketFiles(bucket: bucketName)
        let numFiles = fileList.count
        if numFiles != 0 {
            print("\(numFiles) file\((numFiles > 1) ? "s" : "") in bucket \(bucketName):")
            for name in fileList {
                print("  \(name)")
            }
        } else {
            print("No files found in bucket \(bucketName)")
        }

        // 6. Delete the objects from the bucket.

        print("Deleting the file \(objName) from the bucket \(bucketName)...")
        try await serviceHandler.deleteFile(bucket: bucketName, key: objName)
        print("Deleting the file \(objName) from the bucket \(destBucket)...")
        try await serviceHandler.deleteFile(bucket: destBucket, key: objName)

        // 7. Delete the bucket.
        print("Deleting the bucket \(bucketName)...")
        try await serviceHandler.deleteBucket(name: bucketName)

        print("Done.")
    }
}

//
// Main program entry point.
//
@main
struct Main {
    static func main() async {
        let args = Array(CommandLine.arguments.dropFirst())

        do {
            let command = try ExampleCommand.parse(args)
            try await command.runAsync()
        } catch {
            ExampleCommand.exit(withError: error)
        }
    }    
}

• For API details, see the following topics in AWS SDK for Swift API reference.

  • CopyObject

  • CreateBucket

  • DeleteBucket

  • DeleteObjects

  • GetObject

  • ListObjectsV2

  • PutObject

Actions

CopyObject

The following code example shows how to use CopyObject.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func copyFile(from sourceBucket: String, name: String, to destBucket: String) async throws {
        let srcUrl = ("\(sourceBucket)/\(name)").addingPercentEncoding(withAllowedCharacters: .urlPathAllowed)

        let input = CopyObjectInput(
            bucket: destBucket,
            copySource: srcUrl,
            key: name
        )
        _ = try await client.copyObject(input: input)
    }

• For API details, see CopyObject in AWS SDK for Swift API reference.

CreateBucket

The following code example shows how to use CreateBucket.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func createBucket(name: String) async throws {
        let config = S3ClientTypes.CreateBucketConfiguration(
            locationConstraint: .usEast2
        )
        let input = CreateBucketInput(
            bucket: name,
            createBucketConfiguration: config
        )
        _ = try await client.createBucket(input: input)
    }

• For API details, see CreateBucket in AWS SDK for Swift API reference.

DeleteBucket

The following code example shows how to use DeleteBucket.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func deleteBucket(name: String) async throws {
        let input = DeleteBucketInput(
            bucket: name
        )
        _ = try await client.deleteBucket(input: input)
    }

• For API details, see DeleteBucket in AWS SDK for Swift API reference.

DeleteObject

The following code example shows how to use DeleteObject.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func deleteFile(bucket: String, key: String) async throws {
        let input = DeleteObjectInput(
            bucket: bucket,
            key: key
        )

        do {
            _ = try await client.deleteObject(input: input)
        } catch {
            throw error
        }
    }

• For API details, see DeleteObject in AWS SDK for Swift API reference.

DeleteObjects

The following code example shows how to use DeleteObjects.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func deleteObjects(bucket: String, keys: [String]) async throws {
        let input = DeleteObjectsInput(
            bucket: bucket,
            delete: S3ClientTypes.Delete(
                objects: keys.map({ S3ClientTypes.ObjectIdentifier(key: $0) }),
                quiet: true
            )
        )

        do {
            let output = try await client.deleteObjects(input: input)

            // As of the last update to this example, any errors are returned
            // in the `output` object's `errors` property. If there are any
            // errors in this array, throw an exception. Once the error
            // handling is finalized in later updates to the AWS SDK for
            // Swift, this example will be updated to handle errors better.

            guard let errors = output.errors else {
                return  // No errors.
            }
            if errors.count != 0 {
                throw ServiceHandlerError.deleteObjectsError
            }
        } catch {
            throw error
        }
    }

• For API details, see DeleteObjects in AWS SDK for Swift API reference.

GetObject

The following code example shows how to use GetObject.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Download an object from a bucket to a local file.

    public func downloadFile(bucket: String, key: String, to: String) async throws {
        let fileUrl = URL(fileURLWithPath: to).appendingPathComponent(key)

        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        let output = try await client.getObject(input: input)

        // Get the data stream object. Return immediately if there isn't one.
        guard let body = output.body,
              let data = try await body.readData() else {
            return
        }
        try data.write(to: fileUrl)
    }

Read an object into a Swift Data object.

    public func readFile(bucket: String, key: String) async throws -> Data {
        let input = GetObjectInput(
            bucket: bucket,
            key: key
        )
        let output = try await client.getObject(input: input)

        // Get the stream and return its contents in a `Data` object. If
        // there is no stream, return an empty `Data` object instead.
        guard let body = output.body,
              let data = try await body.readData() else {
            return "".data(using: .utf8)!
        }
        
        return data
    }

• For API details, see GetObject in AWS SDK for Swift API reference.

ListBuckets

The following code example shows how to use ListBuckets.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    /// Return an array containing information about every available bucket.
    /// 
    /// - Returns: An array of ``S3ClientTypes.Bucket`` objects describing
    ///   each bucket.
    public func getAllBuckets() async throws -> [S3ClientTypes.Bucket] {
        let output = try await client.listBuckets(input: ListBucketsInput())

        guard let buckets = output.buckets else {
            return []
        }
        return buckets
    }

• For API details, see ListBuckets in AWS SDK for Swift API reference.

ListObjectsV2

The following code example shows how to use ListObjectsV2.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

    public func listBucketFiles(bucket: String) async throws -> [String] {
        let input = ListObjectsV2Input(
            bucket: bucket
        )
        let output = try await client.listObjectsV2(input: input)
        var names: [String] = []

        guard let objList = output.contents else {
            return []
        }

        for obj in objList {
            if let objName = obj.key {
                names.append(objName)
            }
        }

        return names
    }

• For API details, see ListObjectsV2 in AWS SDK for Swift API reference.

PutObject

The following code example shows how to use PutObject.

SDK for Swift

Note

This is prerelease documentation for an SDK in preview release. It is subject to change.

Note

There's more on GitHub. Find the complete example and learn how to set up and run in the AWS Code Examples Repository.

Upload a file from local storage to a bucket.

    public func uploadFile(bucket: String, key: String, file: String) async throws {
        let fileUrl = URL(fileURLWithPath: file)
        let fileData = try Data(contentsOf: fileUrl)
        let dataStream = ByteStream.data(fileData)

        let input = PutObjectInput(
            body: dataStream,
            bucket: bucket,
            key: key
        )
        _ = try await client.putObject(input: input)
    }

Upload the contents of a Swift Data object to a bucket.

    public func createFile(bucket: String, key: String, withData data: Data) async throws {
        let dataStream = ByteStream.data(data)

        let input = PutObjectInput(
            body: dataStream,
            bucket: bucket,
            key: key
        )
        _ = try await client.putObject(input: input)
    }

• For API details, see PutObject in AWS SDK for Swift API reference.