Uploading an object using multipart upload

To upload a file to an S3 bucket, use the TransferUtility class. When uploading data from a file, you must provide the object's key name. If you don't, the API uses the file name for the key name. When uploading data from a stream, you must provide the object's key name.

To set advanced upload options—such as the part size, the number of threads when uploading the parts concurrently, metadata, the storage class, or ACL—use the TransferUtilityUploadRequest class.

The following C# example uploads a file to an Amazon S3 bucket in multiple parts. It shows how to use various TransferUtility.Upload overloads to upload a file. Each successive call to upload replaces the previous upload. For information about setting up and running the code examples, see Getting Started with the Amazon SDK for .NET in the Amazon SDK for .NET Developer Guide.

using Amazon;
using Amazon.S3;
using Amazon.S3.Transfer;
using System;
using System.IO;
using System.Threading.Tasks;

namespace Amazon.DocSamples.S3
{
    class UploadFileMPUHighLevelAPITest
    {
        private const string bucketName = "*** provide bucket name ***";
        private const string keyName = "*** provide a name for the uploaded object ***";
        private const string filePath = "*** provide the full path name of the file to upload ***";
        // Specify your bucket region (an example region is shown).
        private static readonly RegionEndpoint bucketRegion = RegionEndpoint.USWest2;
        private static IAmazonS3 s3Client;

        public static void Main()
        {
            s3Client = new AmazonS3Client(bucketRegion);
            UploadFileAsync().Wait();
        }

        private static async Task UploadFileAsync()
        {
            try
            {
                var fileTransferUtility =
                    new TransferUtility(s3Client);

                // Option 1. Upload a file. The file name is used as the object key name.
                await fileTransferUtility.UploadAsync(filePath, bucketName);
                Console.WriteLine("Upload 1 completed");

                // Option 2. Specify object key name explicitly.
                await fileTransferUtility.UploadAsync(filePath, bucketName, keyName);
                Console.WriteLine("Upload 2 completed");

                // Option 3. Upload data from a type of System.IO.Stream.
                using (var fileToUpload = 
                    new FileStream(filePath, FileMode.Open, FileAccess.Read))
                {
                    await fileTransferUtility.UploadAsync(fileToUpload,
                                               bucketName, keyName);
                }
                Console.WriteLine("Upload 3 completed");

                // Option 4. Specify advanced settings.
                var fileTransferUtilityRequest = new TransferUtilityUploadRequest
                {
                    BucketName = bucketName,
                    FilePath = filePath,
                    StorageClass = S3StorageClass.StandardInfrequentAccess,
                    PartSize = 6291456, // 6 MB.
                    Key = keyName,
                    CannedACL = S3CannedACL.PublicRead
                };
                fileTransferUtilityRequest.Metadata.Add("param1", "Value1");
                fileTransferUtilityRequest.Metadata.Add("param2", "Value2");

                await fileTransferUtility.UploadAsync(fileTransferUtilityRequest);
                Console.WriteLine("Upload 4 completed");
            }
            catch (AmazonS3Exception e)
            {
                Console.WriteLine("Error encountered on server. Message:'{0}' when writing an object", e.Message);
            }
            catch (Exception e)
            {
                Console.WriteLine("Unknown encountered on server. Message:'{0}' when writing an object", e.Message);
            }

        }
    }
}

For more information about the Go code example for multipart upload, see Upload or download large files to and from Amazon S3 using an Amazon SDK.

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log"
	"os"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/feature/s3/manager"
	"github.com/aws/aws-sdk-go-v2/service/s3"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	"github.com/aws/smithy-go"
)

// BucketBasics encapsulates the Amazon Simple Storage Service (Amazon S3) actions
// used in the examples.
// It contains S3Client, an Amazon S3 service client that is used to perform bucket
// and object actions.
type BucketBasics struct {
	S3Client *s3.Client
}

// UploadLargeObject uses an upload manager to upload data to an object in a bucket.
// The upload manager breaks large data into parts and uploads the parts concurrently.
func (basics BucketBasics) UploadLargeObject(ctx context.Context, bucketName string, objectKey string, largeObject []byte) error {
	largeBuffer := bytes.NewReader(largeObject)
	var partMiBs int64 = 10
	uploader := manager.NewUploader(basics.S3Client, func(u *manager.Uploader) {
		u.PartSize = partMiBs * 1024 * 1024
	})
	_, err := uploader.Upload(ctx, &s3.PutObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
		Body:   largeBuffer,
	})
	if err != nil {
		var apiErr smithy.APIError
		if errors.As(err, &apiErr) && apiErr.ErrorCode() == "EntityTooLarge" {
			log.Printf("Error while uploading object to %s. The object is too large.\n"+
				"The maximum size for a multipart upload is 5TB.", bucketName)
		} else {
			log.Printf("Couldn't upload large object to %v:%v. Here's why: %v\n",
				bucketName, objectKey, err)
		}
	} else {
		err = s3.NewObjectExistsWaiter(basics.S3Client).Wait(
			ctx, &s3.HeadObjectInput{Bucket: aws.String(bucketName), Key: aws.String(objectKey)}, time.Minute)
		if err != nil {
			log.Printf("Failed attempt to wait for object %s to exist.\n", objectKey)
		}
	}

	return err
}

// DownloadLargeObject uses a download manager to download an object from a bucket.
// The download manager gets the data in parts and writes them to a buffer until all of
// the data has been downloaded.
func (basics BucketBasics) DownloadLargeObject(ctx context.Context, bucketName string, objectKey string) ([]byte, error) {
	var partMiBs int64 = 10
	downloader := manager.NewDownloader(basics.S3Client, func(d *manager.Downloader) {
		d.PartSize = partMiBs * 1024 * 1024
	})
	buffer := manager.NewWriteAtBuffer([]byte{})
	_, err := downloader.Download(ctx, buffer, &s3.GetObjectInput{
		Bucket: aws.String(bucketName),
		Key:    aws.String(objectKey),
	})
	if err != nil {
		log.Printf("Couldn't download large object from %v:%v. Here's why: %v\n",
			bucketName, objectKey, err)
	}
	return buffer.Bytes(), err
}

This topic explains how to use the high-level Aws\S3\Model\MultipartUpload\UploadBuilder class from the Amazon SDK for PHP for multipart file uploads. For more information about the Amazon SDK for Ruby API, go to Amazon SDK for Ruby - Version 2.

The following PHP example uploads a file to an Amazon S3 bucket. The example demonstrates how to set parameters for the MultipartUploader object.

 require 'vendor/autoload.php';

use Aws\Exception\MultipartUploadException;
use Aws\S3\MultipartUploader;
use Aws\S3\S3Client;

$bucket = '*** Your Bucket Name ***';
$keyname = '*** Your Object Key ***';

$s3 = new S3Client([
    'version' => 'latest',
    'region'  => 'us-east-1'
]);

// Prepare the upload parameters.
$uploader = new MultipartUploader($s3, '/path/to/large/file.zip', [
    'bucket' => $bucket,
    'key'    => $keyname
]);

// Perform the upload.
try {
    $result = $uploader->upload();
    echo "Upload complete: {$result['ObjectURL']}" . PHP_EOL;
} catch (MultipartUploadException $e) {
    echo $e->getMessage() . PHP_EOL;
}

The following example loads an object using the high-level multipart upload Python API (the TransferManager class).

import sys
import threading

import boto3
from boto3.s3.transfer import TransferConfig


MB = 1024 * 1024
s3 = boto3.resource("s3")


class TransferCallback:
    """
    Handle callbacks from the transfer manager.

    The transfer manager periodically calls the __call__ method throughout
    the upload and download process so that it can take action, such as
    displaying progress to the user and collecting data about the transfer.
    """

    def __init__(self, target_size):
        self._target_size = target_size
        self._total_transferred = 0
        self._lock = threading.Lock()
        self.thread_info = {}

    def __call__(self, bytes_transferred):
        """
        The callback method that is called by the transfer manager.

        Display progress during file transfer and collect per-thread transfer
        data. This method can be called by multiple threads, so shared instance
        data is protected by a thread lock.
        """
        thread = threading.current_thread()
        with self._lock:
            self._total_transferred += bytes_transferred
            if thread.ident not in self.thread_info.keys():
                self.thread_info[thread.ident] = bytes_transferred
            else:
                self.thread_info[thread.ident] += bytes_transferred

            target = self._target_size * MB
            sys.stdout.write(
                f"\r{self._total_transferred} of {target} transferred "
                f"({(self._total_transferred / target) * 100:.2f}%)."
            )
            sys.stdout.flush()


def upload_with_default_configuration(
    local_file_path, bucket_name, object_key, file_size_mb
):
    """
    Upload a file from a local folder to an Amazon S3 bucket, using the default
    configuration.
    """
    transfer_callback = TransferCallback(file_size_mb)
    s3.Bucket(bucket_name).upload_file(
        local_file_path, object_key, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def upload_with_chunksize_and_meta(
    local_file_path, bucket_name, object_key, file_size_mb, metadata=None
):
    """
    Upload a file from a local folder to an Amazon S3 bucket, setting a
    multipart chunk size and adding metadata to the Amazon S3 object.

    The multipart chunk size controls the size of the chunks of data that are
    sent in the request. A smaller chunk size typically results in the transfer
    manager using more threads for the upload.

    The metadata is a set of key-value pairs that are stored with the object
    in Amazon S3.
    """
    transfer_callback = TransferCallback(file_size_mb)

    config = TransferConfig(multipart_chunksize=1 * MB)
    extra_args = {"Metadata": metadata} if metadata else None
    s3.Bucket(bucket_name).upload_file(
        local_file_path,
        object_key,
        Config=config,
        ExtraArgs=extra_args,
        Callback=transfer_callback,
    )
    return transfer_callback.thread_info


def upload_with_high_threshold(local_file_path, bucket_name, object_key, file_size_mb):
    """
    Upload a file from a local folder to an Amazon S3 bucket, setting a
    multipart threshold larger than the size of the file.

    Setting a multipart threshold larger than the size of the file results
    in the transfer manager sending the file as a standard upload instead of
    a multipart upload.
    """
    transfer_callback = TransferCallback(file_size_mb)
    config = TransferConfig(multipart_threshold=file_size_mb * 2 * MB)
    s3.Bucket(bucket_name).upload_file(
        local_file_path, object_key, Config=config, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def upload_with_sse(
    local_file_path, bucket_name, object_key, file_size_mb, sse_key=None
):
    """
    Upload a file from a local folder to an Amazon S3 bucket, adding server-side
    encryption with customer-provided encryption keys to the object.

    When this kind of encryption is specified, Amazon S3 encrypts the object
    at rest and allows downloads only when the expected encryption key is
    provided in the download request.
    """
    transfer_callback = TransferCallback(file_size_mb)
    if sse_key:
        extra_args = {"SSECustomerAlgorithm": "AES256", "SSECustomerKey": sse_key}
    else:
        extra_args = None
    s3.Bucket(bucket_name).upload_file(
        local_file_path, object_key, ExtraArgs=extra_args, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def download_with_default_configuration(
    bucket_name, object_key, download_file_path, file_size_mb
):
    """
    Download a file from an Amazon S3 bucket to a local folder, using the
    default configuration.
    """
    transfer_callback = TransferCallback(file_size_mb)
    s3.Bucket(bucket_name).Object(object_key).download_file(
        download_file_path, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def download_with_single_thread(
    bucket_name, object_key, download_file_path, file_size_mb
):
    """
    Download a file from an Amazon S3 bucket to a local folder, using a
    single thread.
    """
    transfer_callback = TransferCallback(file_size_mb)
    config = TransferConfig(use_threads=False)
    s3.Bucket(bucket_name).Object(object_key).download_file(
        download_file_path, Config=config, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def download_with_high_threshold(
    bucket_name, object_key, download_file_path, file_size_mb
):
    """
    Download a file from an Amazon S3 bucket to a local folder, setting a
    multipart threshold larger than the size of the file.

    Setting a multipart threshold larger than the size of the file results
    in the transfer manager sending the file as a standard download instead
    of a multipart download.
    """
    transfer_callback = TransferCallback(file_size_mb)
    config = TransferConfig(multipart_threshold=file_size_mb * 2 * MB)
    s3.Bucket(bucket_name).Object(object_key).download_file(
        download_file_path, Config=config, Callback=transfer_callback
    )
    return transfer_callback.thread_info


def download_with_sse(
    bucket_name, object_key, download_file_path, file_size_mb, sse_key
):
    """
    Download a file from an Amazon S3 bucket to a local folder, adding a
    customer-provided encryption key to the request.

    When this kind of encryption is specified, Amazon S3 encrypts the object
    at rest and allows downloads only when the expected encryption key is
    provided in the download request.
    """
    transfer_callback = TransferCallback(file_size_mb)

    if sse_key:
        extra_args = {"SSECustomerAlgorithm": "AES256", "SSECustomerKey": sse_key}
    else:
        extra_args = None
    s3.Bucket(bucket_name).Object(object_key).download_file(
        download_file_path, ExtraArgs=extra_args, Callback=transfer_callback
    )
    return transfer_callback.thread_info

The following example shows how to use the low-level Java classes to upload a file. It performs the following steps:

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.*;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class LowLevelMultipartUpload {

    public static void main(String[] args) throws IOException {
        Regions clientRegion = Regions.DEFAULT_REGION;
        String bucketName = "*** Bucket name ***";
        String keyName = "*** Key name ***";
        String filePath = "*** Path to file to upload ***";

        File file = new File(filePath);
        long contentLength = file.length();
        long partSize = 5 * 1024 * 1024; // Set part size to 5 MB.

        try {
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withRegion(clientRegion)
                    .withCredentials(new ProfileCredentialsProvider())
                    .build();

            // Create a list of ETag objects. You retrieve ETags for each object part
            // uploaded,
            // then, after each individual part has been uploaded, pass the list of ETags to
            // the request to complete the upload.
            List<PartETag> partETags = new ArrayList<PartETag>();

            // Initiate the multipart upload.
            InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest(bucketName, keyName);
            InitiateMultipartUploadResult initResponse = s3Client.initiateMultipartUpload(initRequest);

            // Upload the file parts.
            long filePosition = 0;
            for (int i = 1; filePosition < contentLength; i++) {
                // Because the last part could be less than 5 MB, adjust the part size as
                // needed.
                partSize = Math.min(partSize, (contentLength - filePosition));

                // Create the request to upload a part.
                UploadPartRequest uploadRequest = new UploadPartRequest()
                        .withBucketName(bucketName)
                        .withKey(keyName)
                        .withUploadId(initResponse.getUploadId())
                        .withPartNumber(i)
                        .withFileOffset(filePosition)
                        .withFile(file)
                        .withPartSize(partSize);

                // Upload the part and add the response's ETag to our list.
                UploadPartResult uploadResult = s3Client.uploadPart(uploadRequest);
                partETags.add(uploadResult.getPartETag());

                filePosition += partSize;
            }

            // Complete the multipart upload.
            CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest(bucketName, keyName,
                    initResponse.getUploadId(), partETags);
            s3Client.completeMultipartUpload(compRequest);
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}

The following C# example shows how to use the low-level Amazon SDK for .NET multipart upload API to upload a file to an S3 bucket. For information about Amazon S3 multipart uploads, see Uploading and copying objects using multipart upload in Amazon S3.

The following C# example uploads a file to an S3 bucket using the low-level multipart upload API. For information about setting up and running the code examples, see Getting Started with the Amazon SDK for .NET in the Amazon SDK for .NET Developer Guide.

using Amazon;
using Amazon.Runtime;
using Amazon.S3;
using Amazon.S3.Model;
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;

namespace Amazon.DocSamples.S3
{
    class UploadFileMPULowLevelAPITest
    {
        private const string bucketName = "*** provide bucket name ***";
        private const string keyName = "*** provide a name for the uploaded object ***";
        private const string filePath = "*** provide the full path name of the file to upload ***";
        // Specify your bucket region (an example region is shown).
        private static readonly RegionEndpoint bucketRegion = RegionEndpoint.USWest2;
        private static IAmazonS3 s3Client;

        public static void Main()
        {
            s3Client = new AmazonS3Client(bucketRegion);
            Console.WriteLine("Uploading an object");
            UploadObjectAsync().Wait(); 
        }

        private static async Task UploadObjectAsync()
        {
            // Create list to store upload part responses.
            List<UploadPartResponse> uploadResponses = new List<UploadPartResponse>();

            // Setup information required to initiate the multipart upload.
            InitiateMultipartUploadRequest initiateRequest = new InitiateMultipartUploadRequest
            {
                BucketName = bucketName,
                Key = keyName
            };

            // Initiate the upload.
            InitiateMultipartUploadResponse initResponse =
                await s3Client.InitiateMultipartUploadAsync(initiateRequest);

            // Upload parts.
            long contentLength = new FileInfo(filePath).Length;
            long partSize = 5 * (long)Math.Pow(2, 20); // 5 MB

            try
            {
                Console.WriteLine("Uploading parts");
        
                long filePosition = 0;
                for (int i = 1; filePosition < contentLength; i++)
                {
                    UploadPartRequest uploadRequest = new UploadPartRequest
                        {
                            BucketName = bucketName,
                            Key = keyName,
                            UploadId = initResponse.UploadId,
                            PartNumber = i,
                            PartSize = partSize,
                            FilePosition = filePosition,
                            FilePath = filePath
                        };

                    // Track upload progress.
                    uploadRequest.StreamTransferProgress +=
                        new EventHandler<StreamTransferProgressArgs>(UploadPartProgressEventCallback);

                    // Upload a part and add the response to our list.
                    uploadResponses.Add(await s3Client.UploadPartAsync(uploadRequest));

                    filePosition += partSize;
                }

                // Setup to complete the upload.
                CompleteMultipartUploadRequest completeRequest = new CompleteMultipartUploadRequest
                    {
                        BucketName = bucketName,
                        Key = keyName,
                        UploadId = initResponse.UploadId
                     };
                completeRequest.AddPartETags(uploadResponses);

                // Complete the upload.
                CompleteMultipartUploadResponse completeUploadResponse =
                    await s3Client.CompleteMultipartUploadAsync(completeRequest);
            }
            catch (Exception exception)
            {
                Console.WriteLine("An AmazonS3Exception was thrown: { 0}", exception.Message);

                // Abort the upload.
                AbortMultipartUploadRequest abortMPURequest = new AbortMultipartUploadRequest
                {
                    BucketName = bucketName,
                    Key = keyName,
                    UploadId = initResponse.UploadId
                };
               await s3Client.AbortMultipartUploadAsync(abortMPURequest);
            }
        }
        public static void UploadPartProgressEventCallback(object sender, StreamTransferProgressArgs e)
        {
            // Process event. 
            Console.WriteLine("{0}/{1}", e.TransferredBytes, e.TotalBytes);
        }
    }
}

This topic shows how to use the low-level uploadPart method from version 3 of the Amazon SDK for PHP to upload a file in multiple parts. For more information about the Amazon SDK for Ruby API, go to Amazon SDK for Ruby - Version 2.

The following PHP example uploads a file to an Amazon S3 bucket using the low-level PHP API multipart upload.

 require 'vendor/autoload.php';

use Aws\S3\Exception\S3Exception;
use Aws\S3\S3Client;

$bucket = '*** Your Bucket Name ***';
$keyname = '*** Your Object Key ***';
$filename = '*** Path to and Name of the File to Upload ***';

$s3 = new S3Client([
    'version' => 'latest',
    'region'  => 'us-east-1'
]);

$result = $s3->createMultipartUpload([
    'Bucket'       => $bucket,
    'Key'          => $keyname,
    'StorageClass' => 'REDUCED_REDUNDANCY',
    'Metadata'     => [
        'param1' => 'value 1',
        'param2' => 'value 2',
        'param3' => 'value 3'
    ]
]);
$uploadId = $result['UploadId'];

// Upload the file in parts.
try {
    $file = fopen($filename, 'r');
    $partNumber = 1;
    while (!feof($file)) {
        $result = $s3->uploadPart([
            'Bucket'     => $bucket,
            'Key'        => $keyname,
            'UploadId'   => $uploadId,
            'PartNumber' => $partNumber,
            'Body'       => fread($file, 5 * 1024 * 1024),
        ]);
        $parts['Parts'][$partNumber] = [
            'PartNumber' => $partNumber,
            'ETag' => $result['ETag'],
        ];
        $partNumber++;

        echo "Uploading part $partNumber of $filename." . PHP_EOL;
    }
    fclose($file);
} catch (S3Exception $e) {
    $result = $s3->abortMultipartUpload([
        'Bucket'   => $bucket,
        'Key'      => $keyname,
        'UploadId' => $uploadId
    ]);

    echo "Upload of $filename failed." . PHP_EOL;
}

// Complete the multipart upload.
$result = $s3->completeMultipartUpload([
    'Bucket'   => $bucket,
    'Key'      => $keyname,
    'UploadId' => $uploadId,
    'MultipartUpload'    => $parts,
]);
$url = $result['Location'];

echo "Uploaded $filename to $url." . PHP_EOL;