(Delphi ActiveX) Microsoft Graph OAuth2 Client Credentials Grant Flow

Demonstrates how to get a Microsoft Graph access token using the Client Credentials Grant Flow.

You can use the OAuth 2.0 client credentials grant specified in RFC 6749, sometimes called two-legged OAuth, to access web-hosted resources by using the identity of an application. This type of grant is commonly used for server-to-server interactions that must run in the background, without immediate interaction with a user. These types of applications are often referred to as daemons or service accounts.

For more information, see https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow

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;
req: TChilkatHttpRequest;
url: WideString;
resp: IChilkatHttpResponse;
statusCode: Integer;
json: TChilkatJsonObject;

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

http := TChilkatHttp.Create(Self);

req := TChilkatHttpRequest.Create(Self);
req.AddParam('client_secret','CLIENT_SECRET');
req.AddParam('client_id','CLIENT_ID');
// Don't know if the scopes valid for the client credentials grant are different than the scopes for the 3-legged Authorization Code Grant...
req.AddParam('scope','https://graph.microsoft.com/.default');
req.AddParam('grant_type','client_credentials');

// Use your own tenant ID, for example 4d8fdd66-66d1-43b0-ae5c-e31b4b7de5cd
url := 'https://login.microsoftonline.com/TENANT_ID/oauth2/v2.0/token';
resp := http.PostUrlEncoded(url,req.ControlInterface);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

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

json := TChilkatJsonObject.Create(Self);
json.Load(resp.BodyStr);

json.EmitCompact := 0;
Memo1.Lines.Add(json.Emit());

// Sample successful output:

// {
//   "token_type": "Bearer",
//   "expires_in": 3599,
//   "ext_expires_in": 3599,
//   "access_token": "eyJ0eX...K0jOERg"
// }

if (statusCode = 200) then
  begin
    json.WriteFile('qa_data/tokens/msGraphClientCredentialsToken.json');
    Memo1.Lines.Add('Success.');
  end
else
  begin
    Memo1.Lines.Add('Failed.');
  end;
end;