Delphi DLL

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.

Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Xml, Http;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
http: HCkHttp;
bucketName: PWideChar;
strXml: PWideChar;
xml: HCkXml;
ETag: PWideChar;
Key: PWideChar;
LastModified: PWideChar;
ID: PWideChar;
SizeDecimalStr: PWideChar;
StorageClass: PWideChar;
ListBucketResult_xmlns: PWideChar;
i: Integer;
count_i: Integer;
IsTruncated: PWideChar;
MaxKeys: Integer;
Name: PWideChar;

begin
success := False;

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

http := CkHttp_Create();

// keyID = Access Key ID or Access Key
CkHttp_putAwsAccessKey(http,'access-key');

// applicationKey = Secret Access Key or Secret Key
CkHttp_putAwsSecretKey(http,'secret-key');

// Region is the 2nd part of your S3 Endpoint
CkHttp_putAwsEndpoint(http,'s3.us-west-002.backblazeb2.com');

bucketName := 'chilkat-test';

strXml := CkHttp__s3_ListBucketObjects(http,bucketName);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

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

xml := CkXml_Create();
success := CkXml_LoadXml(xml,strXml);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkXml__lastErrorText(xml));
    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 (CkHttp_getLastStatus(http) <> 200) then
  begin
    Memo1.Lines.Add(CkXml__getXml(xml));
    Memo1.Lines.Add('Failed.');
    Exit;
  end;

// A sample response is shown below.
Memo1.Lines.Add(CkXml__getXml(xml));
Memo1.Lines.Add('----');

// 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 := CkXml__getAttrValue(xml,'xmlns');
i := 0;
count_i := CkXml_NumChildrenHavingTag(xml,'Contents');
while i < count_i do
  begin
    CkXml_putI(xml,i);
    ETag := CkXml__getChildContent(xml,'Contents[i]|ETag');
    Key := CkXml__getChildContent(xml,'Contents[i]|Key');
    LastModified := CkXml__getChildContent(xml,'Contents[i]|LastModified');
    ID := CkXml__getChildContent(xml,'Contents[i]|Owner|ID');
    SizeDecimalStr := CkXml__getChildContent(xml,'Contents[i]|Size');
    StorageClass := CkXml__getChildContent(xml,'Contents[i]|StorageClass');
    i := i + 1;
  end;

IsTruncated := CkXml__getChildContent(xml,'IsTruncated');
MaxKeys := CkXml_GetChildIntValue(xml,'MaxKeys');
Name := CkXml__getChildContent(xml,'Name');

CkHttp_Dispose(http);
CkXml_Dispose(xml);

end;