(Delphi DLL) Manage Cloud Storage Bucket Labels

See more Google Cloud Storage Examples

Demonstrates how to add, update, and delete labels for a Cloud Storage bucket.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
sbToken: HCkStringBuilder;
json: HCkJsonObject;
http: HCkHttp;
url: PWideChar;
resp: HCkHttpResponse;
responseCode: Integer;

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

// This example uses a previously obtained access token having permission for the 
// scope "https://www.googleapis.com/auth/cloud-platform"

// In this example, Get Google Cloud Storage OAuth2 Access Token, 
// the service account access token was saved to a text file.  This example fetches the access token from the file..
sbToken := CkStringBuilder_Create();
CkStringBuilder_LoadFile(sbToken,'qa_data/tokens/googleCloudStorageAccessToken.txt','utf-8');

// ---- Step 1
// Create the JSON body of the PATCH request that will be sent.
// This specifies labels to be added, updated, and/or deleted.
// (To delete a label, set its value equal to null.)

// {
//   "labels": {
//     "new_label_key": "new_label_value",
//     "existing_label_key": "updated_label_value",
//     "old_label_key": null
//   }
// }

// ---------
// Important
// ---------
// You can apply multiple labels to each bucket, with a maximum of 64 labels per bucket.

//     - Keys and values cannot be longer than 63 characters each.
//     - Keys and values can only contain lowercase letters, numeric characters, underscores, and dashes. International characters are allowed.
//     - Label keys must start with a lowercase letter and international characters are allowed.
//     - Label keys cannot be empty.

// Build JSON to update labels.
// 
// During the testing of this example, my bucket already has the following labels:
// {
//  "labels": {
//   "test1": "xyz",
//   "test": "abc",
//   "a": "abc"
//  }
// }

// For this example, I'm going to add a label "b", delete the label "test1", and update
// the label "test".
json := CkJsonObject_Create();
CkJsonObject_UpdateString(json,'labels.b','bbb');
CkJsonObject_UpdateString(json,'labels.test','abc123');
CkJsonObject_UpdateNull(json,'labels.test1');

// ---- Step 2
// Send a PATCH equivalent to this curl command

// curl -X PATCH --data-binary @[JSON_FILE_NAME].json \
//     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
//     -H "Content-Type: application/json" \
//     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]?fields=labels"

http := CkHttp_Create();
CkHttp_putAuthToken(http,CkStringBuilder__getAsString(sbToken));

CkHttp_SetUrlVar(http,'bucket_name','chilkat-ocean');
url := 'https://www.googleapis.com/storage/v1/b/{$bucket_name}?fields=labels';
resp := CkHttp_PText(http,'PATCH',url,CkJsonObject__emit(json),'utf-8','application/json',False,False);
if (CkHttp_getLastMethodSuccess(http) = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

responseCode := CkHttpResponse_getStatusCode(resp);
if (responseCode = 401) then
  begin
    Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));
    Memo1.Lines.Add('If invalid credentials, then it is likely the access token expired.');
    Memo1.Lines.Add('Your app should automatically fetch a new access token and re-try.');
    CkHttpResponse_Dispose(resp);
    Exit;
  end;

// Note: A 400 response code is likely caused by illegal characters used for a label name and/or value.

Memo1.Lines.Add('Response code: ' + IntToStr(responseCode));
Memo1.Lines.Add('Response body');
Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));

// A response code = 200 indicates success, and the response body contains the JSON
// for the new/updated set of labels
// Response code: 200
// Response body
// {
//  "labels": {
//   "test": "abc123",
//   "a": "abc",
//   "b": "bbb"
//  }
// }

CkHttpResponse_Dispose(resp);

CkStringBuilder_Dispose(sbToken);
CkJsonObject_Dispose(json);
CkHttp_Dispose(http);

end;