Pascal (Lazarus/Delphi)

Azure Storage: Lease Container

See more Azure Cloud Storage Examples

Azure Storage Blob Service REST API: Sample code to establishes a lock on a container for delete operations. The lock duration can be 15 to 60 seconds, or can be infinite. Pascal (Lazarus/Delphi)

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.Rest,
  Chilkat.AuthAzureStorage,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  bTls: Boolean;
  port: Integer;
  bAutoReconnect: Boolean;
  azAuth: TAuthAzureStorage;
  crypt: TCrypt2;
  guid: string;
  responseStr: string;

begin
  success := False;

  //  Azure Blob Service Example: Lease Container
  //  See also: https://msdn.microsoft.com/en-us/library/azure/jj159103.aspx

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

  rest := TRest.Create;

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

  //  Provide Azure Cloud credentials for the REST call.
  azAuth := TAuthAzureStorage.Create;
  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);

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

  //  The lease ID needs to be a GUID.  (UUID and GUID are synonymous)
  crypt := TCrypt2.Create;
  guid := crypt.GenerateUuid();
  WriteLn('Lease ID: ' + guid);
  success := rest.AddHeader('x-ms-lease-id',guid);

  //  The action can be "acquire", "renew", "change", "release", or "break".
  //  See https://msdn.microsoft.com/en-us/library/azure/jj159103.aspx
  success := rest.AddHeader('x-ms-lease-action','acquire');

  //  The lease duration..
  success := rest.AddHeader('x-ms-lease-duration','15');

  //  In this example, we are acquiring a lease for the container named "mycontainer".
  responseStr := rest.FullRequestNoBody('PUT','/mycontainer?restype=container&comp=lease');
  if (rest.LastMethodSuccess <> True) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  When successful, the Azure Storage service will respond with a 200, 201, or 202 response status code,
  //  with no response body.

  //  The status code depends on the operation:
  //     Acquire: A successful operation returns status code 201 (Created).
  //     Renew: A successful operation returns status code 200 (OK).
  //     Change: A successful operation returns status code 200 (OK).
  //     Release: A successful operation returns status code 200 (OK).
  //     Break: A successful operation returns status code 202 (Accepted).

  if ((rest.ResponseStatusCode < 200) or (rest.ResponseStatusCode > 202)) 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 (if any): ' + responseStr);
      WriteLn('---');
      WriteLn('LastRequestStartLine: ' + rest.LastRequestStartLine);
      WriteLn('LastRequestHeader: ' + rest.LastRequestHeader);
      Exit;
    end;

  WriteLn('Success: Lease acquired.');


  rest.Free;
  azAuth.Free;
  crypt.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.