Delphi DLL

S3 Complete a Multipart Upload

See more Amazon S3 (new) Examples

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>

Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, AuthAws, Rest, Xml;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
xmlInit: HCkXml;
uploadId: PWideChar;
xmlPartsList: HCkXml;
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
authAws: HCkAuthAws;
responseXml: PWideChar;
xml: HCkXml;

begin
success := False;

// 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.

xmlInit := CkXml_Create();
success := CkXml_LoadXmlFile(xmlInit,'s3_multipart_uploads/initiate.xml');
if (success <> True) then
  begin
    Memo1.Lines.Add('Did not find the initiate.xml XML file.');
    Exit;
  end;

uploadId := CkXml__getChildContent(xmlInit,'UploadId');
Memo1.Lines.Add('UploadId = ' + uploadId);

// 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.)
xmlPartsList := CkXml_Create();
success := CkXml_LoadXmlFile(xmlPartsList,'s3_multipart_uploads/partsList.xml');
if (success <> True) then
  begin
    Memo1.Lines.Add('Did not find the partsList.xml XML file.');
    Exit;
  end;

rest := CkRest_Create();

// Connect to the Amazon AWS REST server.
bTls := True;
port := 443;
bAutoReconnect := True;
success := CkRest_Connect(rest,'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.
authAws := CkAuthAws_Create();
CkAuthAws_putAccessKey(authAws,'AWS_ACCESS_KEY');
CkAuthAws_putSecretKey(authAws,'AWS_SECRET_KEY');
CkAuthAws_putServiceName(authAws,'s3');

success := CkRest_SetAuthAws(rest,authAws);

// Set the bucket name via the HOST header.
// In this case, the bucket name is "chilkat100".
CkRest_putHost(rest,'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:
CkRest_AddQueryParam(rest,'uploadId',uploadId);

// Our ObjectName in this case is "somethingBig.zip".
responseXml := CkRest__fullRequestString(rest,'POST','/somethingBig.zip',CkXml__getXml(xmlPartsList));
if (CkRest_getLastMethodSuccess(rest) <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// When successful, the S3 Storage service will respond with a 200 response code,
// with an XML body.  
if (CkRest_getResponseStatusCode(rest) <> 200) then
  begin
    // Examine the request/response to see what happened.
    Memo1.Lines.Add('response status code = ' + IntToStr(CkRest_getResponseStatusCode(rest)));
    Memo1.Lines.Add('response status text = ' + CkRest__responseStatusText(rest));
    Memo1.Lines.Add('response header: ' + CkRest__responseHeader(rest));
    Memo1.Lines.Add('response body: ' + responseXml);
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + CkRest__lastRequestStartLine(rest));
    Memo1.Lines.Add('LastRequestHeader: ' + CkRest__lastRequestHeader(rest));
  end;

// Load the XML response into Chilkat XMl and emit via GetXml to see the XML in a pretty-printed (indented) readable format.
xml := CkXml_Create();
CkXml_LoadXml(xml,responseXml);
Memo1.Lines.Add(CkXml__getXml(xml));
Memo1.Lines.Add('----');

Memo1.Lines.Add('Multipart upload completed.');

CkXml_Dispose(xmlInit);
CkXml_Dispose(xmlPartsList);
CkRest_Dispose(rest);
CkAuthAws_Dispose(authAws);
CkXml_Dispose(xml);

end;