(MFC) S3 Complete a Multipart Upload

This operation completes a multipart upload by assembling previously uploaded parts.

Processing of a Complete Multipart Upload request could take several minutes to complete. 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 whitespace characters to keep the connection from timing out. Because a request could fail after the initial 200 OK response has been sent, it is important that you check the response body to determine whether the request succeeded.

This example sends a POST request to complete a multipart upload, which looks like this:

POST /ObjectName?uploadId=UploadId HTTP/1.1
Host: BucketName.s3.amazonaws.com
Date: Date
Content-Length: Size
Authorization: authorization string

<CompleteMultipartUpload>
  <Part>
    <PartNumber>PartNumber</PartNumber>
    <ETag>ETag</ETag>
  </Part>
  ...
</CompleteMultipartUpload>

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkXml.h>
#include <CkRest.h>
#include <CkAuthAws.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The 1st step in an S3 multipart upload is to initiate it,
    // as shown here: Initiate S3 Multipart Upload

    // The 2nd step is to upload the parts
    // as shown here: S3 Upload Parts

    // The 3rd and final step (this example) is to complete the multipart upload.

    // Other S3 Multipart Upload Examples:
    // Abort Multipart Upload
    // List Parts

    // When the multipart upload was initiated, an UploadId was provided in the XML response, and it 
    // was saved to a file.  Steps 2 and 3 begin by loading the XML and getting
    // the Upload ID.

    CkXml xmlInit;
    bool success = xmlInit.LoadXmlFile("s3_multipart_uploads/initiate.xml");
    if (success != true) {
        strOut.append("Did not find the initiate.xml XML file.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    const char *uploadId = xmlInit.getChildContent("UploadId");
    strOut.append("UploadId = ");
    strOut.append(uploadId);
    strOut.append("\r\n");

    // We'll also need the XML file that contains a record of the parts
    // with part numbers and ETags.  (This file was produced when parts were being uploaded.)
    CkXml xmlPartsList;
    success = xmlPartsList.LoadXmlFile("s3_multipart_uploads/partsList.xml");
    if (success != true) {
        strOut.append("Did not find the partsList.xml XML file.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkRest rest;

    // Connect to the Amazon AWS REST server.
    bool bTls = true;
    int port = 443;
    bool bAutoReconnect = true;
    success = rest.Connect("s3.amazonaws.com",port,bTls,bAutoReconnect);

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

    // Provide AWS credentials for the REST call.
    CkAuthAws authAws;
    authAws.put_AccessKey("AWS_ACCESS_KEY");
    authAws.put_SecretKey("AWS_SECRET_KEY");
    authAws.put_ServiceName("s3");

    success = rest.SetAuthAws(authAws);

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    rest.put_Host("chilkat100.s3.amazonaws.com");

    // The "uploadId=UploadId" must be added as a query parameter.  This allows it to be 
    // incorporated into the AWS signature calculation, which is a requirement.
    // Therefore, we use AddQueryParam:
    rest.AddQueryParam("uploadId",uploadId);

    // Our ObjectName in this case is "somethingBig.zip".
    const char *responseXml = rest.fullRequestString("POST","/somethingBig.zip",xmlPartsList.getXml());
    if (rest.get_LastMethodSuccess() != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // When successful, the S3 Storage service will respond with a 200 response code,
    // with an XML body.  
    if (rest.get_ResponseStatusCode() != 200) {
        // Examine the request/response to see what happened.
        strOut.append("response status code = ");
        strOut.appendInt(rest.get_ResponseStatusCode());
        strOut.append("\r\n");
        strOut.append("response status text = ");
        strOut.append(rest.responseStatusText());
        strOut.append("\r\n");
        strOut.append("response header: ");
        strOut.append(rest.responseHeader());
        strOut.append("\r\n");
        strOut.append("response body: ");
        strOut.append(responseXml);
        strOut.append("\r\n");
        strOut.append("---");
        strOut.append("\r\n");
        strOut.append("LastRequestStartLine: ");
        strOut.append(rest.lastRequestStartLine());
        strOut.append("\r\n");
        strOut.append("LastRequestHeader: ");
        strOut.append(rest.lastRequestHeader());
        strOut.append("\r\n");
    }

    // Load the XML response into Chilkat XMl and emit via GetXml to see the XML in a pretty-printed (indented) readable format.
    CkXml xml;
    xml.LoadXml(responseXml);
    strOut.append(xml.getXml());
    strOut.append("\r\n");
    strOut.append("----");
    strOut.append("\r\n");

    strOut.append("Multipart upload completed.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }