Complete Multipart Upload

Last updated: 2018-07-02 11:41:05



Complete Multipart Upload API request is used to complete the entire multipart upload. You must use this API to complete the multipart upload operation of the entire file when you have uploaded all parts using Upload Parts. When using this API, you need to provide the PartNumber and ETag for every part in request Body, to verify the accuracy of parts.
The merging of parts is required and takes several minutes, thus COS returns status code 200 immediately when the merging process begins. During merging, COS may returns blank information periodically to keep the connection active, until the merging process completes, upon which the COS will return the content of the merged parts in Body.
When this API is called, "400 EntityTooSmall" is returned if the uploaded part is smaller than 1 MB.
"400 InvalidPart" is returned if the numbers of uploaded parts are discontinuous.
"400 InvalidPartOrder" is returned if the part information entries in the request Body are not sorted in ascending order according to their numbers.
"404 NoSuchUpload" is returned if the UploadId does not exist when this API is called.

It is recommended that you complete multipart upload in time or abort the upload operation for the reason that parts that have been uploaded but not aborted can take up storage, incurring cost.



POST /ObjectName?uploadId=UploadId HTTP/1.1
Host: <BucketName>-<APPID>.cos.<Region>
Date: GMT Date
Content-length: Size
Authorization: Auth String

Authorization: Auth String (For more information, please see Request Signature chapter)

Request Line

POST /ObjectName?uploadId=UploadId HTTP/1.1

This API allows POST request.

Request parameter

Example of request line that contains all request parameters.

POST /ObjectName?uploadId=UploadId HTTP/1.1

See the details below:

Parameter Name Description Type Required
uploadId Indicate the ID of current multipart upload.
You can obtain an uploadid when you use the API "Initiate Multipart Upload" to initiate multipart upload. This ID exclusively identifies this multipart data, and the relative position of this multipart in the entire file
String Yes

Request Header

Common Header

This request operation is implemented using common request header. For more information, please see Common Request Headers chapter.

Non-common Header

No particular request header information for this request operation.

Request Body

The specific nodes of the request body for this API request are:


Detailed data content is shown as below:

Node Name (Keyword) Parent Node Description Type Required
CompleteMultipartUpload None Used to describe all information of the current multipart upload operation Container Yes

Content of Container node CompleteMultipartUpload:

Node Name (Keyword) Parent Node Description Type Required
Part CompleteMultipartUpload Used to describe information of every part in the current multipart upload operation Container Yes

Content of Container node Part:

Node Name (Keyword) Parent Node Description Type Required
PartNumber CompleteMultipartUpload.Part Part number String Yes
ETag CompleteMultipartUpload.Part MD5 algorithm check value for every part file String Yes


Response Header

Common Response Header

This response uses common response header. For more information, please see Common Response Headers chapter.

Specific Response Header

No particular response header for this response.

Response Body

application/xml data is returned for the response body, including the complete node data, as show below:


Detailed data content is shown as below:

Node Name (Keyword) Parent Node Description Type
CompleteMultipartUploadResult None Indicate all the returned information Container

Content of Container node CompleteMultipartUploadResult:

Node Name (Keyword) Parent Node Description Type
Location CompleteMultipartUploadResult Domain name for public network access of the created Object URL
Bucket CompleteMultipartUploadResult The target Bucket for multipart upload String
Key CompleteMultipartUploadResult Name of Object String
ETag CompleteMultipartUploadResult MD5 algorithm check value for the merged file String

Practical Case


POST /ObjectName?uploadId=1484728886e63106e87d8207536ae8521c89c42a436fe23bb58854a7bb5e87b7d77d4ddc48 HTTP/1.1
Date: Wed, 18 Jan 2017 16:17:03 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKIDWtTCBYjM5OwLB9CAwA1Qb2ThTSUjfGFO&q-sign-time=1484729794;32557625794&q-key-time=1484729794;32557625794&q-header-list=host&q-url-param-list=uploadId&q-signature=23627c8fddb3823cce4257b33c663fd83f9f820d
Content-Length: 155
Content-Type: application/x-www-form-urlencoded


HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: 277
Connection: keep-alive
Date: Wed, 18 Jan 2017 16:17:03 GMT
Server: tencent-cos
x-cos-request-id: NTg3ZjJlMjVfNDYyMDRlXzM0YzRfMjc1