Delphi DLL

(using AWS Signature Version 2) Streaming Download to File

See more Amazon S3 (new) Examples

The main purpose of this example is to demonstrate how to use the older Signature Version 2 authentication w/ S3. It uses V2 authentication to download a file. 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, Stream;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
rest: HCkRest;
bTls: Boolean;
port: Integer;
bAutoReconnect: Boolean;
authAws: HCkAuthAws;
responseStatusCode: Integer;
bodyStream: HCkStream;
errResponse: PWideChar;

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 Amazon AWS REST server.
bTls := True;
port := 443;
bAutoReconnect := True;
// The file is located in the bucket named "chilkat100", which becomes part of the domain:
success := CkRest_Connect(rest,'chilkat100.s3.amazonaws.com',port,bTls,bAutoReconnect);

// 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');

// For AWS Signature Version 2, the following two properties need to be set:
CkAuthAws_putSignatureVersion(authAws,2);
// See http://docs.aws.amazon.com/AmazonS3/latest/dev/RESTAuthentication.html#ConstructingTheCanonicalizedResourceElement
CkAuthAws_putCanonicalizedResourceV2(authAws,'/chilkat100/starfish.jpg');

success := CkRest_SetAuthAws(rest,authAws);

// Send the request to download the JPG.
success := CkRest_SendReqNoBody(rest,'GET','/starfish.jpg');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

// Read the response header.
responseStatusCode := CkRest_ReadResponseHeader(rest);
if (responseStatusCode < 0) then
  begin
    Memo1.Lines.Add(CkRest__lastErrorText(rest));
    Exit;
  end;

Memo1.Lines.Add('Response status code = ' + IntToStr(responseStatusCode));

// We expect a 200 response status if the JPG data is coming.
// Otherwise, we'll get a string response body with an error message(or no response body).
if (responseStatusCode = 200) then
  begin

    bodyStream := CkStream_Create();

    // The stream's sink will be a file.
    CkStream_putSinkFile(bodyStream,'qa_output/starfish.jpg');

    // Read the response body to the stream.  Given that we've
    // set the stream's sink to a file, it will stream directly
    // to the file.
    success := CkRest_ReadRespBodyStream(rest,bodyStream,True);
    if (success <> True) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
        Exit;
      end;

    Memo1.Lines.Add('Successfully received the JPG file.');

  end
else
  begin
    errResponse := CkRest__readRespBodyString(rest);
    if (CkRest_getLastMethodSuccess(rest) <> True) then
      begin
        Memo1.Lines.Add(CkRest__lastErrorText(rest));
      end
    else
      begin
        Memo1.Lines.Add(errResponse);
      end;
  end;

CkRest_Dispose(rest);
CkAuthAws_Dispose(authAws);
    CkStream_Dispose(bodyStream);

end;