(Delphi ActiveX) Calendar: Refresh Expired OAuth2 Access Token

Refreshes an expired OAuth2 access token.

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
json: TChilkatJsonObject;
success: Integer;
req: TChilkatHttpRequest;
http: TChilkatHttp;
resp: IChilkatHttpResponse;
fac: TCkFileAccess;

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

json := TChilkatJsonObject.Create(Self);
success := json.LoadFile('qa_data/tokens/msGraphCalendar.json');
if (success <> 1) then
  begin
    Exit;
  end;

req := TChilkatHttpRequest.Create(Self);
req.AddParam('grant_type','refresh_token');
req.AddParam('redirect_uri','http://localhost:3017/');
req.AddParam('client_id','MICROSOFT-GRAPH-CLIENT-ID');
req.AddParam('client_secret','MICROSOFT-GRAPH-CLIENT-SECRET');
req.AddParam('refresh_token',json.StringOf('refresh_token'));
req.AddParam('scope','openid profile offline_access user.readwrite calendars.readwrite files.readwrite');

http := TChilkatHttp.Create(Self);

resp := http.PostUrlEncoded('https://login.microsoftonline.com/common/oauth2/v2.0/token',req.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

// Load the JSON response.
json.Load(resp.BodyStr);
json.EmitCompact := 0;

// Show the JSON response.
Memo1.Lines.Add(json.Emit());

Memo1.Lines.Add('Response status code: ' + IntToStr(resp.StatusCode));

// If the response status code is not 200, then it's an error.
if (resp.StatusCode <> 200) then
  begin
    Exit;
  end;

// Save the refreshed access token JSON to a file for future requests.
fac := TCkFileAccess.Create(Self);
fac.WriteEntireTextFile('qa_data/tokens/msGraphCalendar.json',json.Emit(),'utf-8',0);

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