AWS SDK Version 3 for .NET
API Reference

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Completes a multipart upload by assembling previously uploaded parts.

You first initiate the multipart upload and then upload all parts using the UploadPart operation or the UploadPartCopy operation. After successfully uploading all relevant parts of an upload, you call this CompleteMultipartUpload operation to complete the upload. Upon receiving this request, Amazon S3 concatenates all the parts in ascending order by part number to create a new object. In the CompleteMultipartUpload request, you must provide the parts list and ensure that the parts list is complete. The CompleteMultipartUpload API operation concatenates the parts that you provide in the list. For each part in the list, you must provide the PartNumber value and the ETag value that are returned after that part was uploaded.

The processing of a CompleteMultipartUpload request could take several minutes to finalize. After Amazon S3 begins processing the request, it sends an HTTP response header that specifies a 200 OK response. While processing is in progress, Amazon S3 periodically sends white space characters to keep the connection from timing out. A request could fail after the initial 200 OK response has been sent. This means that a 200 OK response can contain either a success or an error. The error response might be embedded in the 200 OK response. If you call this API operation directly, make sure to design your application to parse the contents of the response and handle it appropriately. If you use Amazon Web Services SDKs, SDKs handle this condition. The SDKs detect the embedded error and apply error handling per your configuration settings (including automatically retrying the request as appropriate). If the condition persists, the SDKs throw an exception (or, for the SDKs that don't use exceptions, they return an error).

Note that if CompleteMultipartUpload fails, applications should be prepared to retry any failed requests (including 500 error responses). For more information, see Amazon S3 Error Best Practices.

You can't use Content-Type: application/x-www-form-urlencoded for the CompleteMultipartUpload requests. Also, if you don't provide a Content-Type header, CompleteMultipartUpload can still return a 200 OK response.

For more information about multipart uploads, see Uploading Objects Using Multipart Upload in the Amazon S3 User Guide.

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-zone-id.region-code.amazonaws.com/key-name. Path-style requests are not supported. For more information about endpoints in Availability Zones, see Regional and Zonal endpoints for directory buckets in Availability Zones in the Amazon S3 User Guide. For more information about endpoints in Local Zones, see Available Local Zone for directory buckets in the Amazon S3 User Guide.

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

    If you provide an additional checksum value in your MultipartUpload requests and the object is encrypted with Key Management Service, you must have permission to use the kms:Decrypt action for the CompleteMultipartUpload request to succeed.

  • 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.

    If the object is encrypted with SSE-KMS, you must also have the kms:GenerateDataKey and kms:Decrypt permissions in IAM identity-based policies and KMS key policies for the KMS key.

Special errors
  • Error Code: EntityTooSmall

    • Description: Your proposed upload is smaller than the minimum allowed object size. Each part must be at least 5 MB in size, except the last part.

    • HTTP Status Code: 400 Bad Request

  • Error Code: InvalidPart

    • Description: One or more of the specified parts could not be found. The part might not have been uploaded, or the specified ETag might not have matched the uploaded part's ETag.

    • HTTP Status Code: 400 Bad Request

  • Error Code: InvalidPartOrder

    • Description: The list of parts was not in ascending order. The parts list must be specified in order by part number.

    • HTTP Status Code: 400 Bad Request

  • Error Code: NoSuchUpload

    • Description: The specified multipart upload does not exist. The upload ID might be invalid, or the multipart upload might have been aborted or completed.

    • HTTP Status Code: 404 Not Found

HTTP Host header syntax

Directory buckets - The HTTP Host header syntax is Bucket-name.s3express-zone-id.region-code.amazonaws.com.

The following operations are related to CompleteMultipartUpload:

Note:

This is an asynchronous operation using the standard naming convention for .NET 4.5 or higher. For .NET 3.5 the operation is implemented as a pair of methods using the standard naming convention of BeginCompleteMultipartUpload and EndCompleteMultipartUpload.

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

Syntax

C#
public virtual Task<CompleteMultipartUploadResponse> CompleteMultipartUploadAsync(
         CompleteMultipartUploadRequest request,
         CancellationToken cancellationToken
)

Parameters

request
Type: Amazon.S3.Model.CompleteMultipartUploadRequest

Container for the necessary parameters to execute the CompleteMultipartUpload service method.

cancellationToken
Type: System.Threading.CancellationToken

A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Return Value


The response from the CompleteMultipartUpload service method, as returned by S3.

Version Information

.NET:
Supported in: 8.0 and newer, Core 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5 and newer

See Also