Pascal (Lazarus/Delphi)
Pascal (Lazarus/Delphi)
S3 Upload the Parts for a Multipart Upload
See more Amazon S3 (new) Examples
This example uploads a large file in parts. The multipart upload needs to have been first initiated prior to uploading the parts.See http://docs.aws.amazon.com/AmazonS3/latest/API/mpUploadUploadPart.html for more information about uploading parts.
Chilkat Pascal (Lazarus/Delphi) Downloads
program ChilkatDemo;
// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.
{$IFDEF FPC}
{$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}
uses
{$IFDEF UNIX}
cthreads,
{$ENDIF}
SysUtils,
CkDllLoader,
Chilkat.AuthAws,
Chilkat.FileAccess,
Chilkat.Stream,
Chilkat.StringBuilder,
Chilkat.Xml,
Chilkat.Rest;
// ---------------------------------------------------------------------------
procedure RunDemo;
var
success: Boolean;
xmlInit: TXml;
uploadId: string;
fileToUploadPath: string;
partSize: Integer;
fac: TFileAccess;
numParts: Integer;
partsListFile: string;
partsListXml: TXml;
rest: TRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
authAws: TAuthAws;
partNumber: Integer;
sbPartNumber: TStringBuilder;
bPartAlreadyUploaded: Boolean;
numUploadedParts: Integer;
xRec0: TXml;
foundRec: TXml;
fileStream: TStream;
responseStr: string;
etag: string;
xPart: TXml;
begin
success := False;
// In the 1st step for uploading a large file, the multipart upload was initiated
// as shown here: Initiate Multipart Upload
// Other S3 Multipart Upload Examples:
// Complete Multipart Upload
// Abort Multipart Upload
// List Parts
// When we initiated the multipart upload, we saved the XML response to a file. This
// XML response contains the UploadId. We'll begin by loading that XML and getting
// the Upload ID.
xmlInit := TXml.Create;
success := xmlInit.LoadXmlFile('s3_multipart_uploads/initiate.xml');
if (success <> True) then
begin
WriteLn('Did not find the initiate.xml XML file.');
Exit;
end;
uploadId := xmlInit.GetChildContent('UploadId');
WriteLn('UploadId = ' + uploadId);
// When uploading parts, we need to keep an XML record of each part number
// and its corresponding ETag, which is received in the response for each part.
// There can be up to 10000 parts, numbered 1 to 10000.
// After all parts have been uploaded, the final step will be to complete
// the multipart upload (see Complete Multipart Upload)
// In this example, the large file we want to upload is somethingBig.zip
fileToUploadPath := 's3_multipart_uploads/somethingBig.zip';
// The minimum allowed part size is 5MB (5242880 bytes). The last part can be smaller because
// it will contain the remainder of the file. (This minimum is enforced by the AWS service.)
// We'll use the minimum allowed part size for this example.
partSize := 5242880;
// Let's use Chilkat's FileAccess API to examine the file to be uploaded. We'll get the size
// of the file and find out how many parts will be needed, including the final "partial" part.
fac := TFileAccess.Create;
fac.OpenForRead(fileToUploadPath);
// How many parts will there be if each part is 5242880 bytes?
numParts := fac.GetNumBlocks(partSize);
WriteLn('numParts = ' + numParts);
fac.FileClose();
// Imagine that we may be running this for the 1st time, or maybe we already
// attempted to upload parts, and something failed. Maybe there was a network problem
// the resulted in not all parts getting uploaded. We'll write this code so that if run again,
// it will upload whatever parts haven't yet been uploaded.
// We'll keep a partsList.xml file to record the parts that have already been successfully
// uploaded. If this file does not yet exist, we'll create it..
partsListFile := 's3_multipart_uploads/partsList.xml';
partsListXml := TXml.Create;
if (fac.FileExists(partsListFile) = True) then
begin
partsListXml.LoadXmlFile(partsListFile);
end;
// Make sure the top-level tag is "CompleteMultipartUpload"
partsListXml.Tag := 'CompleteMultipartUpload';
// --------------------------------------
// Before entering the loop to upload parts,
// setup the REST object with AWS authentication,
// and make the initial connection.
rest := TRest.Create;
// Connect to the Amazon AWS REST server.
bTls := True;
port := 443;
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.
authAws := TAuthAws.Create;
authAws.AccessKey := 'AWS_ACCESS_KEY';
authAws.SecretKey := 'AWS_SECRET_KEY';
authAws.ServiceName := 's3';
success := rest.SetAuthAws(authAws);
// Set the bucket name via the HOST header.
// In this case, the bucket name is "chilkat100".
rest.Host := 'chilkat100.s3.amazonaws.com';
// --------------------------------------
partNumber := 1;
sbPartNumber := TStringBuilder.Create;
while (partNumber <= numParts) do
begin
WriteLn('---- ' + partNumber + ' ----');
// This cumbersome way of converting an integer to a string is because
// Chilkat examples are written in a script that is converted to many programming languages.
// At this time, the translator does not have integer-to-string code generation capability..
sbPartNumber.Clear();
sbPartNumber.AppendInt(partNumber);
bPartAlreadyUploaded := False;
// If there are no children, then the XML is empty and no parts have yet been uploaded.
numUploadedParts := partsListXml.NumChildren;
if (numUploadedParts > 0) then
begin
// If some parts have been uploaded, check to see if this particular part was already upload.
// If so, then it can be skipped.
// Position ourselves at the 1st record.
xRec0 := partsListXml.GetChild(0);
foundRec := xRec0.FindNextRecord('PartNumber',sbPartNumber.GetAsString());
if (xRec0.LastMethodSuccess = True) then
begin
bPartAlreadyUploaded := True;
WriteLn('Part ' + partNumber + ' was previously uploaded.');
WriteLn(foundRec.GetXml());
foundRec.Free;
end;
xRec0.Free;
end;
// If this part was not already uploaded, we need to upload.
// Also update the partsListXml and save as each part is successfully uploaded.
if (bPartAlreadyUploaded = False) then
begin
WriteLn('Uploading part ' + partNumber + ' ...');
// Setup the stream source for the large file to be uploaded..
fileStream := TStream.Create;
fileStream.SourceFile := fileToUploadPath;
// The Chilkat Stream API has features to make uploading a parts
// of a file easy. Indicate the part size by setting the SourceFilePartSize
// property.
fileStream.SourceFilePartSize := partSize;
// Our HTTP start line to upload a part will look like this:
// PUT /ObjectName?partNumber=PartNumber&uploadId=UploadId HTTP/1.1
// Set the query params. We'll need partNumber and uploadId.
// Make sure the query params from previous iterations are clear.
rest.ClearAllQueryParams();
rest.AddQueryParam('partNumber',sbPartNumber.GetAsString());
rest.AddQueryParam('uploadId',uploadId);
// Upload this particular file part.
// Tell the fileStream which part is being uploaded.
// Our partNumber is 1-based (the 1st part is at index 1), but the fileStream's SourceFilePart
// property is 0-based. Therefore we use partNumber-1.
fileStream.SourceFilePart := partNumber - 1;
// Because the SourceFilePart and SourceFilePartSize properties are set, the stream will
// will provide just that part of the file.
responseStr := rest.FullRequestStream('PUT','/somethingBig.zip',fileStream);
if (rest.LastMethodSuccess <> True) then
begin
WriteLn(rest.LastErrorText);
Exit;
end;
if (rest.ResponseStatusCode <> 200) then
begin
// Examine the request/response to see what happened.
WriteLn('response status code = ' + rest.ResponseStatusCode);
WriteLn('response status text = ' + rest.ResponseStatusText);
WriteLn('response header: ' + rest.ResponseHeader);
WriteLn('response body: ' + responseStr);
WriteLn('---');
WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
Exit;
end;
// OK, this part was uploaded..
// The response will have a 0-length body. The only information we need is the
// ETag response header field.
etag := rest.ResponseHdrByName('ETag');
// It should be present, but just in case there was no ETag header...
if (rest.LastMethodSuccess <> True) then
begin
WriteLn('No ETag response header found!');
WriteLn('response header: ' + rest.ResponseHeader);
Exit;
end;
// We need to add record to the partsListXml.
// The record will look like this:
// <Part>
// <PartNumber>PartNumber</PartNumber>
// <ETag>ETag</ETag>
// </Part>
xPart := partsListXml.NewChild('Part','');
xPart.NewChildInt2('PartNumber',partNumber);
xPart.NewChild2('ETag',etag);
xPart.Free;
success := partsListXml.SaveXml(partsListFile);
if (success <> True) then
begin
WriteLn(partsListXml.LastErrorText);
Exit;
end;
WriteLn('-- Part ' + partNumber + ' uploaded. ---------------------');
end;
partNumber := partNumber + 1;
end;
WriteLn('Finished. All parts uploaded.');
xmlInit.Free;
fac.Free;
partsListXml.Free;
rest.Free;
authAws.Free;
sbPartNumber.Free;
fileStream.Free;
end;
// ---------------------------------------------------------------------------
begin
try
RunDemo;
except
on E: Exception do
WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
end;
WriteLn;
{$IFDEF MSWINDOWS}
WriteLn('Press Enter to exit...');
ReadLn;
{$ENDIF}
end.