(Delphi DLL) Get Google API Access Token using P12 Service Account Key

Demonstrates how to get a Google API access token using a P12 service account key.

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, Pfx, AuthGoogle, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
pfx: HCkPfx;
success: Boolean;
gAuth: HCkAuthGoogle;
iss: PWideChar;
scope: PWideChar;
oauth_sub: PWideChar;
numSec: Integer;
tlsSock: HCkSocket;

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

// --------------------------------------------------------------------------------
// For a step-by-step guide for setting up your Google Workspace service account,
// see Setup Google Workspace Account for Sending SMTP GMail from a Service Account
// --------------------------------------------------------------------------------

// First load the PKCS12 (.p12 / .pfx) into a PFX object.
pfx := CkPfx_Create();
success := CkPfx_LoadPfxFile(pfx,'qa_data/pfx/chilkat25-cbd7b42afbd8.p12','notasecret');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkPfx__lastErrorText(pfx));
    Exit;
  end;

gAuth := CkAuthGoogle_Create();
success := CkAuthGoogle_SetP12(gAuth,pfx);

// The ISS is your service account email address ending in gserviceaccount.com.
iss := 'chilkatsvc@chilkat25.iam.gserviceaccount.com';

// The scope is always the following string:
scope := 'https://mail.google.com/';

// The sub is your company email address
oauth_sub := 'info@chilkat.xyz';

// The access token is valid for this number of seconds.
numSec := 3600;

CkAuthGoogle_putEmailAddress(gAuth,iss);
CkAuthGoogle_putScope(gAuth,scope);
CkAuthGoogle_putExpireNumSeconds(gAuth,numSec);
CkAuthGoogle_putSubEmailAddress(gAuth,oauth_sub);

// Connect to www.googleapis.com
tlsSock := CkSocket_Create();
success := CkSocket_Connect(tlsSock,'www.googleapis.com',443,True,5000);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tlsSock));
    Exit;
  end;

// Send the request to obtain the access token.
success := CkAuthGoogle_ObtainAccessToken(gAuth,tlsSock);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkAuthGoogle__lastErrorText(gAuth));
    Exit;
  end;

// Examine the access token:
Memo1.Lines.Add('Access Token: ' + CkAuthGoogle__accessToken(gAuth));

CkPfx_Dispose(pfx);
CkAuthGoogle_Dispose(gAuth);
CkSocket_Dispose(tlsSock);

end;