(Delphi ActiveX) Dropbox Refresh OAuth2 Access Token

See more Dropbox Examples

Demonstrates how to mint a new access token using the refresh token obtained when originally getting the OAuth2 access token.

For more information, see https://www.dropbox.com/developers/documentation/http/documentation

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: TChilkatHttp;
success: Integer;
json: TChilkatJsonObject;
req: TChilkatHttpRequest;
resp: IChilkatHttpResponse;
sbResponseBody: TChilkatStringBuilder;
jResp: TChilkatJsonObject;
respStatusCode: Integer;
access_token: WideString;

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

http := TChilkatHttp.Create(Self);

// Implements the following CURL command:

// curl -X GET https://api.dropbox.com/oauth2/token \
//     -d grant_type=refresh_token \
//     -d refresh_token=<YOUR_REFRESH_TOKEN> \
//     -u <YOUR_APP_KEY>:<YOUR_APP_SECRET>

// Use the following online tool to generate HTTP code from a CURL command
// Convert a cURL Command to HTTP Source Code

http.Login := 'DROPBOX_APP_KEY';
http.Password := 'DROPBOX_APP_SECRET';

// Get the refresh token from the JSON we saved when originally getting the access token.
// (See Get Dropbox OAuth2 Access Token w/ Refresh Token
json := TChilkatJsonObject.Create(Self);
success := json.LoadFile('qa_data/tokens/dropbox.json');
if (success = 0) then
  begin
    Memo1.Lines.Add(json.LastErrorText);
    Exit;
  end;

req := TChilkatHttpRequest.Create(Self);
req.AddParam('grant_type','refresh_token');
req.AddParam('refresh_token',json.StringOf('refresh_token'));

resp := http.PostUrlEncoded('https://api.dropbox.com/oauth2/token',req.ControlInterface);
if (http.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

sbResponseBody := TChilkatStringBuilder.Create(Self);
resp.GetBodySb(sbResponseBody.ControlInterface);

jResp := TChilkatJsonObject.Create(Self);
jResp.LoadSb(sbResponseBody.ControlInterface);
jResp.EmitCompact := 0;

Memo1.Lines.Add('Response Body:');
Memo1.Lines.Add(jResp.Emit());

respStatusCode := resp.StatusCode;
Memo1.Lines.Add('Response Status Code = ' + IntToStr(respStatusCode));
if (respStatusCode >= 400) then
  begin
    Memo1.Lines.Add('Response Header:');
    Memo1.Lines.Add(resp.Header);
    Memo1.Lines.Add('Failed.');

    Exit;
  end;

// Sample JSON response:
// (Sample code for parsing the JSON response is shown below)

// {
//   "access_token": "sl.AC75WPYRqOi0mxcRqlimbV9FKHu04biz5qHwatG3MTgzFK7kLrGVlM9EgP4603tE7bWw0s1rMbTKiHsf37TUshPYvq-3r0qeBr_PrZIAibN8XOQicvboiOnqx6JrDekq-w8D-tE",
//   "token_type": "bearer",
//   "expires_in": 14400
// }

access_token := jResp.StringOf('access_token');
Memo1.Lines.Add('New Access Token: ' + access_token);

// Perhaps update our Dropbox JSON file with the new access token.
// (The existing refresh token does not change, and can be used over and over to mint new access tokens.)
json.UpdateString('access_token',access_token);

json.WriteFile('qa_data/tokens/dropbox.json');
end;