Delphi DLL

Calendar: Refresh Expired OAuth2 Access Token

See more Microsoft Calendar Examples

Refreshes an expired OAuth2 access token. Delphi 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
success: Boolean;
json: HCkJsonObject;
req: HCkHttpRequest;
http: HCkHttp;
resp: HCkHttpResponse;
fac: HCkFileAccess;

begin
success := False;

// 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();

CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putContentType(req,'application/x-www-form-urlencoded');

resp := CkHttpResponse_Create();
success := CkHttp_HttpReq(http,'https://login.microsoftonline.com/common/oauth2/v2.0/token',req,resp);
if (success = False) 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;

// 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);
CkHttpResponse_Dispose(resp);
CkFileAccess_Dispose(fac);

end;