Delphi DLL Requires Chilkat v11.0.0+

Generate an AWS (S3) Pre-Signed URL to Download File

See more Amazon S3 (new) Examples

Demonstrates how to generate a pre-signed URL to download a file from the Amazon S3 service. Delphi DLL

var
success: Boolean;
http: HCkHttp;
bucketName: PWideChar;
objectName: PWideChar;
localFilePath: PWideChar;
awsService: PWideChar;
numSecondsValid: Integer;
bUseHttps: Boolean;
preSignedUrl: PWideChar;

begin
success := False;

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

http := CkHttp_Create();

CkHttp_putAwsAccessKey(http,'AWS_ACCESS_KEY');
CkHttp_putAwsSecretKey(http,'AWS_SECRET_KEY');

//  Make sure to set your AWS region correctly
CkHttp_putAwsRegion(http,'us-east-1');

bucketName := 'chilkat100';
objectName := 'starfish/starfish.jpg';
localFilePath := 'qa_output/starfish.jpg';
awsService := 's3';

//  The signed URL will be valid for this number of seconds:
numSecondsValid := 86400;

//  Choose between a URL beginning with "http://" or "https://"...
bUseHttps := False;

//  Generate the pre-signed URL
preSignedUrl := CkHttp__s3_GenPresignedUrl(http,'GET',bUseHttps,bucketName,objectName,numSecondsValid,awsService);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

//  The following URL can be copy-and-pasted into a browser..
Memo1.Lines.Add('Pre-Signed AWS S3 URL: ' + preSignedUrl);

//  Here's an example of a pre-signed URL. 
//  This URL will only work within 1 day (86400 seconds) after the time this example was published.
//  
//      http://chilkat100.s3.amazonaws.com/starfish/starfish.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=16QXXDGY83AJJR6RVQ02%2F20170111%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20170111T161959Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=72bf4fd9a15d7bbcdd313a3318d937a778905f62a3fbff9b789d8dc28acd9232

//  Now try to do an HTTP Download using the signed URL.
success := CkHttp_Download(http,preSignedUrl,'c:/temp/qa_output/starfish.jpg');
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

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

CkHttp_Dispose(http);