Lazarus Pascal

Backblaze S3 List Bucket Objects

See more Backblaze S3 Examples

Demonstrates how to list the objects in a bucket.

The Chilkat S3 functions in the HTTP class are compatible with the Backblaze service. However, because of some specific issues, Chilkat v9.5.0.89 or later is needed.

Lazarus Pascal

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.Xml,
  Chilkat.Http;

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

procedure RunDemo;
var
  success: Boolean;
  http: THttp;
  bucketName: string;
  strXml: string;
  xml: TXml;
  ETag: string;
  Key: string;
  LastModified: string;
  ID: string;
  SizeDecimalStr: string;
  StorageClass: string;
  ListBucketResult_xmlns: string;
  i: Integer;
  count_i: Integer;
  IsTruncated: string;
  MaxKeys: Integer;
  Name: string;

begin
  success := False;

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

  http := THttp.Create;

  //  keyID = Access Key ID or Access Key
  http.AwsAccessKey := 'access-key';

  //  applicationKey = Secret Access Key or Secret Key
  http.AwsSecretKey := 'secret-key';

  //  Region is the 2nd part of your S3 Endpoint
  http.AwsEndpoint := 's3.us-west-002.backblazeb2.com';

  bucketName := 'chilkat-test';

  strXml := http.S3_ListBucketObjects(bucketName);
  if (http.LastMethodSuccess <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  WriteLn('Response status code = ' + http.LastStatus);

  xml := TXml.Create;
  success := xml.LoadXml(strXml);
  if (success <> True) then
    begin
      WriteLn(xml.LastErrorText);
      Exit;
    end;

  //  If the response status code was not 200, then the XML response is not a 
  //  listing of objects, but instead contains error information.
  if (http.LastStatus <> 200) then
    begin
      WriteLn(xml.GetXml());
      WriteLn('Failed.');
      Exit;
    end;

  //  A sample response is shown below.
  WriteLn(xml.GetXml());
  WriteLn('----');

  //  Use this online tool to generate parsing code from sample XML: 
  //  Generate Parsing Code from XML

  //  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  //  <ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
  //      <Contents>
  //          <ETag>"303fb46cf341094fef6274b7789cd6aa"</ETag>
  //          <Key>orchard.json</Key>
  //          <LastModified>2021-10-30T14:45:52.000Z</LastModified>
  //          <Owner>
  //              <ID>f2ebbc5f792c</ID>
  //              <DisplayName/>
  //          </Owner>
  //          <Size>22</Size>
  //          <StorageClass>STANDARD</StorageClass>
  //      </Contents>
  //      <Contents>
  //          <ETag>"a8551f0a5437f43a796fca7623ee9232"</ETag>
  //          <Key>seahorse.jpg</Key>
  //          <LastModified>2021-10-30T14:38:53.000Z</LastModified>
  //          <Owner>
  //              <ID>f2ebbc5f792c</ID>
  //              <DisplayName/>
  //          </Owner>
  //          <Size>24388</Size>
  //          <StorageClass>STANDARD</StorageClass>
  //      </Contents>
  //      <IsTruncated>false</IsTruncated>
  //      <MaxKeys>1000</MaxKeys>
  //      <Name>chilkat-test</Name>
  //      <Prefix/>
  //      <Marker/>
  //  </ListBucketResult>

  ListBucketResult_xmlns := xml.GetAttrValue('xmlns');
  i := 0;
  count_i := xml.NumChildrenHavingTag('Contents');
  while i < count_i do
    begin
      xml.I := i;
      ETag := xml.GetChildContent('Contents[i]|ETag');
      Key := xml.GetChildContent('Contents[i]|Key');
      LastModified := xml.GetChildContent('Contents[i]|LastModified');
      ID := xml.GetChildContent('Contents[i]|Owner|ID');
      SizeDecimalStr := xml.GetChildContent('Contents[i]|Size');
      StorageClass := xml.GetChildContent('Contents[i]|StorageClass');
      i := i + 1;
    end;

  IsTruncated := xml.GetChildContent('IsTruncated');
  MaxKeys := xml.GetChildIntValue('MaxKeys');
  Name := xml.GetChildContent('Name');


  http.Free;
  xml.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.