Delphi DLL

Adding x-ms-range header to Azure Blob Download

See more Azure Cloud Storage Examples

Demonstrates how to add an x-ms-range header to an Azure blob download. Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
azAuth: HCkAuthAzureStorage;
sb: HCkStringBuilder;

begin
success := False;

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

rest := CkRest_Create();

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

// Provide Azure Cloud credentials for the REST call.
azAuth := CkAuthAzureStorage_Create();
CkAuthAzureStorage_putAccessKey(azAuth,'AZURE_ACCESS_KEY');
// The account name used here should match the 1st part of the domain passed in the call to Connect (above).
CkAuthAzureStorage_putAccount(azAuth,'chilkat');
CkAuthAzureStorage_putScheme(azAuth,'SharedKey');
CkAuthAzureStorage_putService(azAuth,'Blob');
// This causes the "x-ms-version: 2021-08-06" header to be automatically added.
CkAuthAzureStorage_putXMsVersion(azAuth,'2021-08-06');
success := CkRest_SetAuthAzureStorage(rest,azAuth);

// 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.

// Add the x-ms-range header.
// See x-ms-range Header Format
// The file we're downloading contains "Hello World!", so we'll download just the "World!" part..
CkRest_AddHeader(rest,'x-ms-range','bytes=6-');

// The Azure blob container is "test", the file is "helloWorld.txt"
sb := CkStringBuilder_Create();
success := CkRest_FullRequestNoBodySb(rest,'GET','/test/helloWorld.txt',sb);
if (success = False) 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('---');
    Memo1.Lines.Add('LastRequestStartLine: ' + CkRest__lastRequestStartLine(rest));
    Memo1.Lines.Add('LastRequestHeader: ' + CkRest__lastRequestHeader(rest));
    Exit;
  end;

Memo1.Lines.Add(CkStringBuilder__getAsString(sb));

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

CkRest_Dispose(rest);
CkAuthAzureStorage_Dispose(azAuth);
CkStringBuilder_Dispose(sb);

end;