(Delphi ActiveX) Upload File in Blocks (with Content-MD5 header) and Commit the Block List

Demonstrates how to upload a file in blocks and then commit the block list. This example includes a Content-MD5 header for each block.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
rest: TChilkatRest;
bTls: Integer;
port: Integer;
bAutoReconnect: Integer;
success: Integer;
azAuth: TChilkatAuthAzureStorage;
xml: TChilkatXml;
fac: TCkFileAccess;
blockSize: Integer;
numBlocks: Integer;
crypt: TChilkatCrypt2;
sbResponseBody: TChilkatStringBuilder;
uriPath: TChilkatStringBuilder;
blockId: WideString;
dataBlock: TChilkatBinData;
contentMd5: WideString;
i: Integer;
xmlStr: WideString;
responseStr: WideString;

begin
// Azure Blob Service Example: Upload a file in blocks, and then commit the block list.
// See also: https://msdn.microsoft.com/en-us/library/azure/dd135726.aspx

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

rest := TChilkatRest.Create(Self);

// Connect to the Azure Storage Blob Service
bTls := 1;
port := 443;
bAutoReconnect := 1;
// In this example, the storage account name is "chilkat".
success := rest.Connect('chilkat.blob.core.windows.net',port,bTls,bAutoReconnect);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// Provide Azure Cloud credentials for the REST call.
azAuth := TChilkatAuthAzureStorage.Create(Self);
azAuth.AccessKey := 'AZURE_ACCESS_KEY';
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
azAuth.Account := 'chilkat';
azAuth.Scheme := 'SharedKey';
azAuth.Service := 'Blob';
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
azAuth.XMsVersion := '2021-08-06';
success := rest.SetAuthAzureStorage(azAuth.ControlInterface);

// Note: The application does not need to explicitly set the following
// headers: Content-Length, x-ms-date, Authorization.  These headers
// are automatically set by Chilkat.

// As the blocks are uploaded, we'll keep an XML block list for the subsequent commit..
xml := TChilkatXml.Create(Self);
xml.Tag := 'BlockList';

// Any type of file can be uploaded in this way.  It can a text file, binary file, anything...
// This example will upload an XML file that is approximately 275K in size.  It can be downloaded
// at http://www.chilkatsoft.com/hamlet.xml
fac := TCkFileAccess.Create(Self);
success := fac.OpenForRead('qa_data/xml/hamlet.xml');
// Assuming success for the example..

// We'll upload in 16K blocks (normally a program would upload in larger block sizes than this,
// but this is just an example...)
blockSize := 16384;

// How many 16K blocks?  (Including 1 for the last partial block)
numBlocks := fac.GetNumBlocks(blockSize);

crypt := TChilkatCrypt2.Create(Self);
crypt.HashAlgorithm := 'md5';

sbResponseBody := TChilkatStringBuilder.Create(Self);
uriPath := TChilkatStringBuilder.Create(Self);

dataBlock := TChilkatBinData.Create(Self);

i := 0;
while i < numBlocks do
  begin

    dataBlock.Clear();
    success := fac.ReadBlockBd(i,blockSize,dataBlock.ControlInterface);
    if (success = 0) then
      begin
        Memo1.Lines.Add(fac.LastErrorText);
        Exit;
      end;

    // Generate a base64 block ID.  
    // (Chilkat provides a helper method named GenBlockId to make this easy)
    // A pre-base64 encoded block ID length of 4 is sufficient in this case because
    // this file certainly won't have more than 99,999 blocks..
    blockId := fac.GenBlockId(i,4,'base64');

    // Add this blockId to the list of blocks to be committed.
    xml.NewChild2('Latest',blockId);

    // Build the URI path
    uriPath.Clear();
    success := uriPath.Append('/mycontainer/hamlet.xml?comp=block&blockId=');
    success := uriPath.Append(blockId);

    contentMd5 := crypt.HashBdENC(dataBlock.ControlInterface);
    rest.AddHeader('Content-MD5',contentMd5);

    // Upload this block..
    sbResponseBody.Clear();
    success := rest.FullRequestBd('PUT',uriPath.GetAsString(),dataBlock.ControlInterface,sbResponseBody.ControlInterface);
    if (success = 0) then
      begin
        Memo1.Lines.Add(rest.LastErrorText);
        Exit;
      end;

    // Verify that we received a 201 status code.
    if (rest.ResponseStatusCode <> 201) then
      begin
        // Examine the request/response to see what happened.
        Memo1.Lines.Add('response status code = ' + IntToStr(rest.ResponseStatusCode));
        Memo1.Lines.Add('response status text = ' + rest.ResponseStatusText);
        Memo1.Lines.Add('response header: ' + rest.ResponseHeader);
        Memo1.Lines.Add('response body (if any): ' + sbResponseBody.GetAsString());
        Memo1.Lines.Add('---');
        Memo1.Lines.Add('LastRequestStartLine: ' + rest.LastRequestStartLine);
        Memo1.Lines.Add('LastRequestHeader: ' + rest.LastRequestHeader);
        Exit;
      end;

    i := i + 1;
  end;

fac.FileClose();

// Now commit the blocks.
// Let's have a look at the XML that will commit the blocks:
xmlStr := xml.GetXml();
Memo1.Lines.Add(xmlStr);

// The XML will look like this:

// <?xml version="1.0" encoding="utf-8" ?>
// <BlockList>
//     <Latest>MDAwMA==</Latest>
//     <Latest>MDAwMQ==</Latest>
//     <Latest>MDAwMg==</Latest>
//     <Latest>MDAwMw==</Latest>
//     <Latest>MDAwNA==</Latest>
//     <Latest>MDAwNQ==</Latest>
//     <Latest>MDAwNg==</Latest>
//     <Latest>MDAwNw==</Latest>
//     <Latest>MDAwOA==</Latest>
//     <Latest>MDAwOQ==</Latest>
//     <Latest>MDAxMA==</Latest>
//     <Latest>MDAxMQ==</Latest>
//     <Latest>MDAxMg==</Latest>
//     <Latest>MDAxMw==</Latest>
//     <Latest>MDAxNA==</Latest>
//     <Latest>MDAxNQ==</Latest>
//     <Latest>MDAxNg==</Latest>
//     <Latest>MDAxNw==</Latest>
// </BlockList>

// --------------------------------------------------------------------------
// IMPORTANT: Remove the Content-MD5 header previously set in the loop above.
// --------------------------------------------------------------------------
rest.RemoveHeader('Content-MD5');

// Send the PUT Block List...
responseStr := rest.FullRequestString('PUT','/mycontainer/hamlet.xml?comp=blocklist',xmlStr);
if (rest.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(rest.LastErrorText);
    Exit;
  end;

// When successful, the Azure Storage service will respond with a 201 response status code,
// with no response body.

if (rest.ResponseStatusCode <> 201) then
  begin
    // Examine the request/response to see what happened.
    Memo1.Lines.Add('response status code = ' + IntToStr(rest.ResponseStatusCode));
    Memo1.Lines.Add('response status text = ' + rest.ResponseStatusText);
    Memo1.Lines.Add('response header: ' + rest.ResponseHeader);
    Memo1.Lines.Add('response body (if any): ' + responseStr);
    Memo1.Lines.Add('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + rest.LastRequestStartLine);
    Memo1.Lines.Add('LastRequestHeader: ' + rest.LastRequestHeader);
    Exit;
  end;

Memo1.Lines.Add('Success.');
end;