(Delphi DLL) Calendar: Refresh Expired OAuth2 Access Token

Refreshes an expired OAuth2 access token.

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, HttpRequest, HttpResponse, JsonObject, FileAccess;

...

procedure TForm1.Button1Click(Sender: TObject);
var
json: HCkJsonObject;
success: Boolean;
req: HCkHttpRequest;
http: HCkHttp;
resp: HCkHttpResponse;
fac: HCkFileAccess;

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

json := CkJsonObject_Create();
success := CkJsonObject_LoadFile(json,'qa_data/tokens/msGraphCalendar.json');
if (success <> True) then
  begin
    Exit;
  end;

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

http := CkHttp_Create();

resp := CkHttp_PostUrlEncoded(http,'https://login.microsoftonline.com/common/oauth2/v2.0/token',req);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

// Load the JSON response.
CkJsonObject_Load(json,CkHttpResponse__bodyStr(resp));
CkJsonObject_putEmitCompact(json,False);

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

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

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

CkHttpResponse_Dispose(resp);

// Save the refreshed access token JSON to a file for future requests.
fac := CkFileAccess_Create();
CkFileAccess_WriteEntireTextFile(fac,'qa_data/tokens/msGraphCalendar.json',CkJsonObject__emit(json),'utf-8',False);

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

CkJsonObject_Dispose(json);
CkHttpRequest_Dispose(req);
CkHttp_Dispose(http);
CkFileAccess_Dispose(fac);

end;