(Delphi DLL) 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 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;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: HCkHttp;
req: HCkHttpRequest;
url: PWideChar;
resp: HCkHttpResponse;
statusCode: Integer;
json: HCkJsonObject;

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

http := CkHttp_Create();

req := CkHttpRequest_Create();
CkHttpRequest_AddParam(req,'client_secret','CLIENT_SECRET');
CkHttpRequest_AddParam(req,'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...
CkHttpRequest_AddParam(req,'scope','https://graph.microsoft.com/.default');
CkHttpRequest_AddParam(req,'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 := CkHttp_PostUrlEncoded(http,url,req);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

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

json := CkJsonObject_Create();
CkJsonObject_Load(json,CkHttpResponse__bodyStr(resp));
CkHttpResponse_Dispose(resp);

CkJsonObject_putEmitCompact(json,False);
Memo1.Lines.Add(CkJsonObject__emit(json));

// Sample successful output:

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

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

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

end;