Pascal (Lazarus/Delphi)

Get OAuth2 Access Token for Azure Registered App

See more OAuth2 Examples

Demonstrates how to get OAuth2 access token for an Azure Registered App from a desktop application or script. This example demonstrates the OAuth2 authorization flow.

This example requires Chilkat v10.1.2 or greater.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.FileAccess,
  Chilkat.OAuth2,
  Chilkat.JsonObject,
  Chilkat.CkDateTime;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  oauth2: TOAuth2;
  url: string;
  numMsWaited: Integer;
  json: TJsonObject;
  dtExpire: TCkDateTime;
  fac: TFileAccess;

begin
  success := False;

  //  To further clarify, see OAuth 2.0 Authorization Flow

  oauth2 := TOAuth2.Create;

  //  This should be the port in the localhost callback URL for your app.  
  //  The callback URL would look like "http://localhost:3017/" if the port number is 3017.
  oauth2.ListenPort := 3017;

  //  ----------------------------------------------------------------------------------------------------------
  //  The screenshot at the bottom of this page shows how we created the Azure App Registration for this example.
  //  ----------------------------------------------------------------------------------------------------------

  //  Note: The endpoint depends on the Azure App Registration.
  //  See How to Choose the Correct Endpoints for your Azure App Registration
  oauth2.AuthorizationEndpoint := 'https://login.microsoftonline.com/common/oauth2/v2.0/authorize';
  oauth2.TokenEndpoint := 'https://login.microsoftonline.com/common/oauth2/v2.0/token';

  //  Replace these with actual values.
  oauth2.ClientId := 'CLIENT_ID';

  //  This is for Require Proof Key for Code Exchange (PKCE)
  //  See OAuth2 PKCE Explained
  oauth2.CodeChallenge := True;
  oauth2.CodeChallengeMethod := 'S256';

  //  Provide a SPACE separated list of scopes.
  //  See https://developer.microsoft.com/en-us/graph/docs/authorization/permission_scopes 

  //  Important: To get a refresh token in the final response, ask for "offline_access" scope
  oauth2.Scope := 'openid profile offline_access user.readwrite mail.readwrite mail.send files.readwrite';

  //  Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
  url := oauth2.StartAuth();
  if (oauth2.LastMethodSuccess <> True) then
    begin
      WriteLn(oauth2.LastErrorText);
      Exit;
    end;

  //  Launch the default browser on the system and navigate to the url.
  //  The LaunchBrowser method was added in Chilkat v10.1.2.
  success := oauth2.LaunchBrowser(url);
  if (success = False) then
    begin
      WriteLn(oauth2.LastErrorText);
      Exit;
    end;

  //  Wait for the user to approve or deny authorization in the browser.
  numMsWaited := 0;
  while (numMsWaited < 90000) and (oauth2.AuthFlowState < 3) do
    begin
      oauth2.SleepMs(100);
      numMsWaited := numMsWaited + 100;
    end;

  //  If the browser does not respond within the specified time, AuthFlowState will be:
  //  
  //  1: Waiting for Redirect – The OAuth2 background thread is waiting for the browser's redirect request.
  //  2: Waiting for Final Response – The thread is awaiting the final access token response.
  //  In either case, cancel the background task initiated by StartAuth.

  if (oauth2.AuthFlowState < 3) then
    begin
      oauth2.Cancel();
      WriteLn('No response from the browser!');
      Exit;
    end;

  //  Check AuthFlowState to determine if authorization was granted, denied, or failed:
  //  
  //  3: Success – OAuth2 flow completed, the background thread exited, and the successful response is in AccessTokenResponse.
  //  4: Access Denied – OAuth2 flow completed, the background thread exited, and the error response is in AccessTokenResponse.
  //  5: Failure – OAuth2 flow failed before completion, the background thread exited, and error details are in FailureInfo.

  if (oauth2.AuthFlowState = 5) then
    begin
      WriteLn('OAuth2 failed to complete.');
      WriteLn(oauth2.FailureInfo);
      Exit;
    end;

  if (oauth2.AuthFlowState = 4) then
    begin
      WriteLn('OAuth2 authorization was denied.');
      WriteLn(oauth2.AccessTokenResponse);
      Exit;
    end;

  if (oauth2.AuthFlowState <> 3) then
    begin
      WriteLn('Unexpected AuthFlowState:' + oauth2.AuthFlowState);
      Exit;
    end;

  WriteLn('OAuth2 authorization granted!');
  WriteLn('Access Token = ' + oauth2.AccessToken);

  //  When the token is near expiration, your app can refresh as shown here:
  //  Refresh Expiring OAuth2 Access Token for Azure Registered App

  //  Get the full JSON response:
  json := TJsonObject.Create;
  json.Load(oauth2.AccessTokenResponse);
  json.EmitCompact := False;

  //  The JSON response looks like this:

  //  {
  //    "token_type": "Bearer",
  //    "scope": "User.Read Mail.ReadWrite Mail.Send",
  //    "expires_in": 3600,
  //    "ext_expires_in": 0,
  //    "access_token": "EwBAA8l6B...",
  //    "refresh_token": "MCRMdbe...",
  //    "id_token": "eyJ0eXA..."
  //  }

  //  If an "expires_on" member does not exist, then add the JSON member by
  //  getting the current system date/time and adding the "expires_in" seconds.
  //  This way we'll know when the token expires.
  if (json.HasMember('expires_on') <> True) then
    begin
      dtExpire := TCkDateTime.Create;
      dtExpire.SetFromCurrentSystemTime();
      dtExpire.AddSeconds(json.IntOf('expires_in'));
      json.AppendString('expires_on',dtExpire.GetAsUnixTimeStr(False));
    end;

  WriteLn(json.Emit());

  //  Save the JSON to a file for future requests.
  fac := TFileAccess.Create;
  fac.WriteEntireTextFile('qa_data/tokens/_myAzureApp.json',json.Emit(),'utf-8',False);

  //  This is a screenshot of how we created the Azure App for this example:
  //  


  oauth2.Free;
  json.Free;
      dtExpire.Free;
  fac.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.