AWS SDK Version 3 for .NET
API Reference

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Container for the parameters to the InitiateMultipartUpload operation. This action initiates a multipart upload and returns an upload ID. This upload ID is used to associate all of the parts in the specific multipart upload. You specify this upload ID in each of your subsequent upload part requests (see UploadPart). You also include this upload ID in the final request to either complete or abort the multipart upload request. For more information about multipart uploads, see Multipart Upload Overview in the Amazon S3 User Guide.

After you initiate a multipart upload and upload one or more parts, to stop being charged for storing the uploaded parts, you must either complete or abort the multipart upload. Amazon S3 frees up the space used to store the parts and stops charging you for storing them only after you either complete or abort a multipart upload.

If you have configured a lifecycle rule to abort incomplete multipart uploads, the created multipart upload must be completed within the number of days specified in the bucket lifecycle configuration. Otherwise, the incomplete multipart upload becomes eligible for an abort action and Amazon S3 aborts the multipart upload. For more information, see Aborting Incomplete Multipart Uploads Using a Bucket Lifecycle Configuration.

  • Directory buckets - S3 Lifecycle is not supported by directory buckets.

  • Directory buckets - For directory buckets, you must make requests for this API operation to the Zonal endpoint. These endpoints support virtual-hosted-style requests in the format https://bucket_name.s3express-az_id.region.amazonaws.com/key-name. Path-style requests are not supported. For more information, see Regional and Zonal endpoints in the Amazon S3 User Guide.

Request signing

For request signing, multipart upload is just a series of regular requests. You initiate a multipart upload, send one or more requests to upload parts, and then complete the multipart upload process. You sign each request individually. There is nothing special about signing multipart upload requests. For more information about signing, see Authenticating Requests (Amazon Web Services Signature Version 4) in the Amazon S3 User Guide.

Permissions

  • General purpose bucket permissions - For information about the permissions required to use the multipart upload API, see Multipart upload and permissions in the Amazon S3 User Guide.

    To perform a multipart upload with encryption by using an Amazon Web Services KMS key, the requester must have permission to the kms:Decrypt and kms:GenerateDataKey* actions on the key. These permissions are required because Amazon S3 must decrypt and read data from the encrypted file parts before it completes the multipart upload. For more information, see Multipart upload API and permissions and Protecting data using server-side encryption with Amazon Web Services KMS in the Amazon S3 User Guide.

  • Directory bucket permissions - To grant access to this API operation on a directory bucket, we recommend that you use the CreateSession API operation for session-based authorization. Specifically, you grant the s3express:CreateSession permission to the directory bucket in a bucket policy or an IAM identity-based policy. Then, you make the CreateSession API call on the bucket to obtain a session token. With the session token in your request header, you can make API requests to this operation. After the session token expires, you make another CreateSession API call to generate a new session token for use. Amazon Web Services CLI or SDKs create session and refresh the session token automatically to avoid service interruptions when a session expires. For more information about authorization, see CreateSession.

Encryption

  • General purpose buckets - Server-side encryption is for data encryption at rest. Amazon S3 encrypts your data as it writes it to disks in its data centers and decrypts it when you access it. Amazon S3 automatically encrypts all new objects that are uploaded to an S3 bucket. When doing a multipart upload, if you don't specify encryption information in your request, the encryption setting of the uploaded parts is set to the default encryption configuration of the destination bucket. By default, all buckets have a base level of encryption configuration that uses server-side encryption with Amazon S3 managed keys (SSE-S3). If the destination bucket has a default encryption configuration that uses server-side encryption with an Key Management Service (KMS) key (SSE-KMS), or a customer-provided encryption key (SSE-C), Amazon S3 uses the corresponding KMS key, or a customer-provided key to encrypt the uploaded parts. When you perform a CreateMultipartUpload operation, if you want to use a different type of encryption setting for the uploaded parts, you can request that Amazon S3 encrypts the object with a different encryption key (such as an Amazon S3 managed key, a KMS key, or a customer-provided key). When the encryption setting in your request is different from the default encryption configuration of the destination bucket, the encryption setting in your request takes precedence. If you choose to provide your own encryption key, the request headers you provide in UploadPart and UploadPartCopy requests must match the headers you used in the CreateMultipartUpload request.

    • Use KMS keys (SSE-KMS) that include the Amazon Web Services managed key (aws/s3) and KMS customer managed keys stored in Key Management Service (KMS) – If you want Amazon Web Services to manage the keys used to encrypt data, specify the following headers in the request.

      • x-amz-server-side-encryption

      • x-amz-server-side-encryption-aws-kms-key-id

      • x-amz-server-side-encryption-context

      • If you specify x-amz-server-side-encryption:aws:kms, but don't provide x-amz-server-side-encryption-aws-kms-key-id, Amazon S3 uses the Amazon Web Services managed key (aws/s3 key) in KMS to protect the data.

      • To perform a multipart upload with encryption by using an Amazon Web Services KMS key, the requester must have permission to the kms:Decrypt and kms:GenerateDataKey* actions on the key. These permissions are required because Amazon S3 must decrypt and read data from the encrypted file parts before it completes the multipart upload. For more information, see Multipart upload API and permissions and Protecting data using server-side encryption with Amazon Web Services KMS in the Amazon S3 User Guide.

      • If your Identity and Access Management (IAM) user or role is in the same Amazon Web Services account as the KMS key, then you must have these permissions on the key policy. If your IAM user or role is in a different account from the key, then you must have the permissions on both the key policy and your IAM user or role.

      • All GET and PUT requests for an object protected by KMS fail if you don't make them by using Secure Sockets Layer (SSL), Transport Layer Security (TLS), or Signature Version 4. For information about configuring any of the officially supported Amazon Web Services SDKs and Amazon Web Services CLI, see Specifying the Signature Version in Request Authentication in the Amazon S3 User Guide.

      For more information about server-side encryption with KMS keys (SSE-KMS), see Protecting Data Using Server-Side Encryption with KMS keys in the Amazon S3 User Guide.

    • Use customer-provided encryption keys (SSE-C) – If you want to manage your own encryption keys, provide all the following headers in the request.

      • x-amz-server-side-encryption-customer-algorithm

      • x-amz-server-side-encryption-customer-key

      • x-amz-server-side-encryption-customer-key-MD5

      For more information about server-side encryption with customer-provided encryption keys (SSE-C), see Protecting data using server-side encryption with customer-provided encryption keys (SSE-C) in the Amazon S3 User Guide.

  • Directory buckets -For directory buckets, only server-side encryption with Amazon S3 managed keys (SSE-S3) (AES256) is supported.

HTTP Host header syntax

Directory buckets - The HTTP Host header syntax is Bucket_name.s3express-az_id.region.amazonaws.com.

The following operations are related to CreateMultipartUpload:

Inheritance Hierarchy

System.Object
  Amazon.Runtime.AmazonWebServiceRequest
    Amazon.S3.Model.PutWithACLRequest
      Amazon.S3.Model.InitiateMultipartUploadRequest

Namespace: Amazon.S3.Model
Assembly: AWSSDK.S3.dll
Version: 3.x.y.z

Syntax

C# 
public class InitiateMultipartUploadRequest : PutWithACLRequest
         IAmazonWebServiceRequest

The InitiateMultipartUploadRequest type exposes the following members

Constructors

NameDescription
Public Method InitiateMultipartUploadRequest()

Properties

NameTypeDescription
Public Property BucketKeyEnabled System.Boolean

Gets and sets the property BucketKeyEnabled.

Specifies whether Amazon S3 should use an S3 Bucket Key for object encryption with server-side encryption using AWS KMS (SSE-KMS). Setting this header to true causes Amazon S3 to use an S3 Bucket Key for object encryption with SSE-KMS.

Specifying this header with an object action doesn't affect bucket-level settings for S3 Bucket Key.

This functionality is not supported for directory buckets.

Public Property BucketName System.String

Gets and sets the property BucketName.

The name of the bucket where the multipart upload is initiated and where the object is uploaded.

Directory buckets - When you use this operation with a directory bucket, you must use virtual-hosted-style requests in the format Bucket_name.s3express-az_id.region.amazonaws.com. Path-style requests are not supported. Directory bucket names must be unique in the chosen Availability Zone. Bucket names must follow the format bucket_base_name--az-id--x-s3 (for example, DOC-EXAMPLE-BUCKET--usw2-az1--x-s3). For information about bucket naming restrictions, see Directory bucket naming rules in the Amazon S3 User Guide.

Access points - When you use this action with an access point, you must provide the alias of the access point in place of the bucket name or specify the access point ARN. When using the access point ARN, you must direct requests to the access point hostname. The access point hostname takes the form AccessPointName-AccountId.s3-accesspoint.Region.amazonaws.com. When using this action with an access point through the Amazon Web Services SDKs, you provide the access point ARN in place of the bucket name. For more information about access point ARNs, see Using access points in the Amazon S3 User Guide.

Access points and Object Lambda access points are not supported by directory buckets.

S3 on Outposts - When you use this action with Amazon S3 on Outposts, you must direct requests to the S3 on Outposts hostname. The S3 on Outposts hostname takes the form AccessPointName-AccountId.outpostID.s3-outposts.Region.amazonaws.com. When you use this action with S3 on Outposts through the Amazon Web Services SDKs, you provide the Outposts access point ARN in place of the bucket name. For more information about S3 on Outposts ARNs, see What is S3 on Outposts? in the Amazon S3 User Guide.

Public Property CannedACL Amazon.S3.S3CannedACL

A canned access control list (ACL) to apply to the object. Please refer to Amazon.S3.S3CannedACL for information on S3 Canned ACLs.

  • This functionality is not supported for directory buckets.

  • This functionality is not supported for Amazon S3 on Outposts.

Public Property ChecksumAlgorithm Amazon.S3.ChecksumAlgorithm

Gets and sets the property ChecksumAlgorithm.

Indicates the algorithm you want Amazon S3 to use to create the checksum for the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

Public Property ContentType System.String

This is a convenience property for Headers.ContentType.

Public Property ExpectedBucketOwner System.String

Gets and sets the property ExpectedBucketOwner.

The account ID of the expected bucket owner. If the account ID that you provide does not match the actual owner of the bucket, the request fails with the HTTP status code 403 Forbidden (access denied).

Public Property Grants System.Collections.Generic.List<Amazon.S3.Model.S3Grant> Inherited from Amazon.S3.Model.PutWithACLRequest.
Public Property Headers Amazon.S3.Model.HeadersCollection

The collection of headers for the request.

Public Property Key System.String

The key of the object to create or update.

Public Property Metadata Amazon.S3.Model.MetadataCollection

The collection of meta data for the request.

Public Property ObjectLockLegalHoldStatus Amazon.S3.ObjectLockLegalHoldStatus

Gets and sets the property ObjectLockLegalHoldStatus.

Specifies whether you want to apply a legal hold to the uploaded object.

This functionality is not supported for directory buckets.

Public Property ObjectLockMode Amazon.S3.ObjectLockMode

Gets and sets the property ObjectLockMode.

Specifies the Object Lock mode that you want to apply to the uploaded object.

This functionality is not supported for directory buckets.

Public Property ObjectLockRetainUntilDate System.DateTime

Gets and sets the property ObjectLockRetainUntilDate.

Specifies the date and time when you want the Object Lock to expire.

This functionality is not supported for directory buckets.

Public Property RequestPayer Amazon.S3.RequestPayer

Confirms that the requester knows that she or he will be charged for the request. Bucket owners need not specify this parameter in their requests.

Public Property ServerSideEncryptionCustomerMethod Amazon.S3.ServerSideEncryptionCustomerMethod

The Server-side encryption algorithm to be used with the customer provided key.

This functionality is not supported for directory buckets.

Public Property ServerSideEncryptionCustomerProvidedKey System.String

The base64-encoded encryption key for Amazon S3 to use to encrypt the object

Using the encryption key you provide as part of your request Amazon S3 manages both the encryption, as it writes to disks, and decryption, when you access your objects. Therefore, you don't need to maintain any data encryption code. The only thing you do is manage the encryption keys you provide.

When you retrieve an object, you must provide the same encryption key as part of your request. Amazon S3 first verifies the encryption key you provided matches, and then decrypts the object before returning the object data to you.

Important: Amazon S3 does not store the encryption key you provide.

This functionality is not supported for directory buckets.

Public Property ServerSideEncryptionCustomerProvidedKeyMD5 System.String

The MD5 of the customer encryption key specified in the ServerSideEncryptionCustomerProvidedKey property. The MD5 is base 64 encoded. This field is optional, the SDK will calculate the MD5 if this is not set.

This functionality is not supported for directory buckets.

Public Property ServerSideEncryptionKeyManagementServiceEncryptionContext System.String

Specifies the AWS KMS Encryption Context to use for object encryption. The value of this header is a base64-encoded UTF-8 string holding JSON with the encryption context key-value pairs.

Specifies the Amazon Web Services KMS Encryption Context to use for object encryption. The value of this header is a base64-encoded UTF-8 string holding JSON with the encryption context key-value pairs.

This functionality is not supported for directory buckets.

Public Property ServerSideEncryptionKeyManagementServiceKeyId System.String

Specifies the ID of the symmetric encryption customer managed key to use for object encryption. All GET and PUT requests for an object protected by Amazon Web Services KMS will fail if not made via SSL or using SigV4. For information about configuring using any of the officially supported Amazon Web Services SDKs and Amazon Web Services CLI, see Specifying the Signature Version in Request Authentication in the Amazon S3 User Guide.

This functionality is not supported for directory buckets.

Public Property ServerSideEncryptionMethod Amazon.S3.ServerSideEncryptionMethod

Gets and sets the property ServerSideEncryptionMethod.

The server-side encryption algorithm used when you store this object in Amazon S3 (for example, AES256, aws:kms).

For directory buckets, only server-side encryption with Amazon S3 managed keys (SSE-S3) (AES256) is supported.

Public Property StorageClass Amazon.S3.S3StorageClass

Gets and sets the property StorageClass.

By default, Amazon S3 uses the STANDARD Storage Class to store newly created objects. The STANDARD storage class provides high durability and high availability. Depending on performance needs, you can specify a different Storage Class. For more information, see Storage Classes in the Amazon S3 User Guide.

  • For directory buckets, only the S3 Express One Zone storage class is supported to store newly created objects.

  • Amazon S3 on Outposts only uses the OUTPOSTS Storage Class.

Public Property TagSet System.Collections.Generic.List<Amazon.S3.Model.Tag>

The tag-set for the object. The tag-set must be encoded as URL Query parameters.

This functionality is not supported for directory buckets.

Public Property WebsiteRedirectLocation System.String

Gets and sets the property WebsiteRedirectLocation.

If the bucket is configured as a website, redirects requests for this object to another object in the same bucket or to an external URL. Amazon S3 stores the value of this header in the object metadata.

This functionality is not supported for directory buckets.

Examples

This example shows how to upload 13MB of data using mutlipart upload.
The data is contained in a stream and the upload is done in 3 parts: 5MB, 5MB, then the remainder.

Multipart Upload Sample


int MB = (int)Math.Pow(2, 20);

// Create a client
AmazonS3Client client = new AmazonS3Client();

// Define input stream
Stream inputStream = Create13MBDataStream();

// Initiate multipart upload
InitiateMultipartUploadRequest initRequest = new InitiateMultipartUploadRequest
{
    BucketName = "SampleBucket",
    Key = "Item1"
};
InitiateMultipartUploadResponse initResponse = client.InitiateMultipartUpload(initRequest);

// Upload part 1
UploadPartRequest uploadRequest = new UploadPartRequest
{
    BucketName = "SampleBucket",
    Key = "Item1",
    UploadId = initResponse.UploadId,
    PartNumber = 1,
    PartSize = 5 * MB,
    InputStream = inputStream
};
UploadPartResponse up1Response = client.UploadPart(uploadRequest);

// Upload part 2
uploadRequest = new UploadPartRequest
{
    BucketName = "SampleBucket",
    Key = "Item1",
    UploadId = initResponse.UploadId,
    PartNumber = 2,
    PartSize = 5 * MB,
    InputStream = inputStream
};
UploadPartResponse up2Response = client.UploadPart(uploadRequest);

// Upload part 3
uploadRequest = new UploadPartRequest
{
    BucketName = "SampleBucket",
    Key = "Item1",
    UploadId = initResponse.UploadId,
    PartNumber = 3,
    InputStream = inputStream
};
UploadPartResponse up3Response = client.UploadPart(uploadRequest);

// List parts for current upload
ListPartsRequest listPartRequest = new ListPartsRequest
{
    BucketName = "SampleBucket",
    Key = "Item1",
    UploadId = initResponse.UploadId
};
ListPartsResponse listPartResponse = client.ListParts(listPartRequest);
Debug.Assert(listPartResponse.Parts.Count == 3);

// Complete the multipart upload
CompleteMultipartUploadRequest compRequest = new CompleteMultipartUploadRequest
{
    BucketName = "SampleBucket",
    Key = "Item1",
    UploadId = initResponse.UploadId,
    PartETags = new List<PartETag>
    {
        new PartETag { ETag = up1Response.ETag, PartNumber = 1 },
        new PartETag { ETag = up2Response.ETag, PartNumber = 2 },
        new PartETag { ETag = up3Response.ETag, PartNumber = 3 }
    }
};
CompleteMultipartUploadResponse compResponse = client.CompleteMultipartUpload(compRequest);

Version Information

.NET Core App:
Supported in: 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5, 4.0, 3.5