(Delphi DLL) Datev OAuth2 Access Token

See more Datev Examples

Note: This example requires Chilkat v10.1.3 or greater.

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, OAuth2, StringBuilder;

...

procedure TForm1.Button1Click(Sender: TObject);
var
oauth2: HCkOAuth2;
url: PWideChar;
success: Boolean;
numMsWaited: Integer;
sbJson: HCkStringBuilder;

begin
// To further clarify, see OAuth 2.0 Authorization Flow

oauth2 := CkOAuth2_Create();

// Your Datev app should use "http://localhost" (no trailing forward slash) for the redirect URL.
CkOAuth2_putListenPort(oauth2,3017);

// 

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://login.datev.de/openidsandbox/authorize');
CkOAuth2_putTokenEndpoint(oauth2,'https://sandbox-api.datev.de/token');

// Replace this with your actual client ID.
CkOAuth2_putClientId(oauth2,'DATEV_CLIENT_ID');
CkOAuth2_putClientSecret(oauth2,'DATEV_CLIENT_SECRET');

CkOAuth2_putCodeChallenge(oauth2,True);
CkOAuth2_putCodeChallengeMethod(oauth2,'S256');

CkOAuth2_putScope(oauth2,'openid profile email datev:accounting:clients accounting:documents datev:accounting:extf-files-import');

// Begin the OAuth2 authorization code flow.  This returns a URL that should be loaded in a browser.
url := CkOAuth2__startAuth(oauth2);
if (CkOAuth2_getLastMethodSuccess(oauth2) <> True) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    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 := CkOAuth2_LaunchBrowser(oauth2,url);
if (success = False) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

// Wait for the interactive user to grant permission in the interactive browser session.
// We'll wait for a max of 90 seconds.
numMsWaited := 0;
while (numMsWaited < 90000) and (CkOAuth2_getAuthFlowState(oauth2) < 3) do
  begin
    CkOAuth2_SleepMs(oauth2,100);
    numMsWaited := numMsWaited + 100;
  end;

// If there was no response from the browser within 90 seconds, then 
// the AuthFlowState will be equal to 1 or 2.
// 1: Waiting for Redirect. The OAuth2 background thread is waiting to receive the redirect HTTP request from the browser.
// 2: Waiting for Final Response. The OAuth2 background thread is waiting for the final access token response.
// In that case, cancel the background task started in the call to StartAuth.
if (CkOAuth2_getAuthFlowState(oauth2) < 3) then
  begin
    CkOAuth2_Cancel(oauth2);
    Memo1.Lines.Add('No response from the browser!');
    Exit;
  end;

// Check the AuthFlowState to see if authorization was granted, denied, or if some error occurred
// The possible AuthFlowState values are:
// 3: Completed with Success. The OAuth2 flow has completed, the background thread exited, and the successful JSON response is available in AccessTokenResponse property.
// 4: Completed with Access Denied. The OAuth2 flow has completed, the background thread exited, and the error JSON is available in AccessTokenResponse property.
// 5: Failed Prior to Completion. The OAuth2 flow failed to complete, the background thread exited, and the error information is available in the FailureInfo property.
if (CkOAuth2_getAuthFlowState(oauth2) = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(CkOAuth2__failureInfo(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) = 4) then
  begin
    Memo1.Lines.Add('OAuth2 authorization was denied.');
    Memo1.Lines.Add(CkOAuth2__accessTokenResponse(oauth2));
    Exit;
  end;

if (CkOAuth2_getAuthFlowState(oauth2) <> 3) then
  begin
    Memo1.Lines.Add('Unexpected AuthFlowState:' + IntToStr(CkOAuth2_getAuthFlowState(oauth2)));
    Exit;
  end;

// Save the full JSON access token response to a file.
sbJson := CkStringBuilder_Create();
CkStringBuilder_Append(sbJson,CkOAuth2__accessTokenResponse(oauth2));
CkStringBuilder_WriteFile(sbJson,'qa_data/tokens/datev.json','utf-8',False);

// The saved JSON response looks like this:

// {
// 	"refresh_token": "ZDA5Y .... FFhTXc9",
// 	"refresh_token_expires_in": 39600,
// 	"id_token": "eyJ .... Q9w",
// 	"access_token": "MTM .... 1UDA9",
// 	"token_type": "bearer",
// 	"expires_in": 900		
// }

Memo1.Lines.Add('OAuth2 authorization granted!');
Memo1.Lines.Add('Access Token = ' + CkOAuth2__accessToken(oauth2));

CkOAuth2_Dispose(oauth2);
CkStringBuilder_Dispose(sbJson);

end;