(Delphi ActiveX) GeoOp OAuth2 Authorisation Code Grant (Public App)

Demonstrates how to get an access token for a GeoOp Third-Party Public Application using the Authorisation Code Grant flow.

Note: This example requires Chilkat v9.5.0.63 or greater.

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
oauth2: TChilkatOAuth2;
success: Integer;
url: WideString;
numMsWaited: Integer;
fac: TCkFileAccess;

begin
// Note: This example requires Chilkat v9.5.0.63 or greater.

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

oauth2 := TChilkatOAuth2.Create(Self);

// This should match the Site URL configured for your GeoOp Application, such as "http://localhost:3017/"
oauth2.ListenPort := 3017;

oauth2.AuthorizationEndpoint := 'https://login.geoop.com/oauth2/code';
oauth2.TokenEndpoint := 'https://login.geoop.com/oauth2/token';

// Replace the client ID with an actual value.
oauth2.ClientId := 'GEOOP-CLIENT-ID';
// The ClientSecret should remain empty for a GeoOp public application
oauth2.ClientSecret := '';

// We need a few special settings for GeoOp
oauth2.Scope := 'default';
oauth2.CodeChallenge := 0;
// Setting LocalHost equal to "none" prevents the "redirect_uri" query param from being sent in the initial HTTP request.
// Note: The GeoOp Application should still have a redirect URL specified as "http://localhost:3017/", where the port
// number matches the ListenPort above.
oauth2.LocalHost := 'none';

// Begin the OAuth2 three-legged flow.  This returns a URL that should be loaded in a browser.
url := oauth2.StartAuth();
if (oauth2.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    Exit;
  end;

// At this point, your application should load the URL in a browser.
// For example, 
// in C#:  System.Diagnostics.Process.Start(url);
// in Java: Desktop.getDesktop().browse(new URI(url));
// in VBScript: Set wsh=WScript.CreateObject("WScript.Shell")
//              wsh.Run url
// in Xojo: ShowURL(url)  (see http://docs.xojo.com/index.php/ShowURL)
// in Dataflex: Runprogram Background "c:\Program Files\Internet Explorer\iexplore.exe" sUrl        
// The GeoOp account owner would interactively accept or deny the authorization request.
// System.Diagnostics.Process.Start(url);

// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...
// Add the code to load the url in a web browser here...

// Now wait for the authorization.
// We'll wait for a max of 30 seconds.
numMsWaited := 0;
while (numMsWaited < 30000) and (oauth2.AuthFlowState < 3) do
  begin
    oauth2.SleepMs(100);
    numMsWaited := numMsWaited + 100;
  end;

// If there was no response from the browser within 30 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 (oauth2.AuthFlowState < 3) then
  begin
    oauth2.Cancel();
    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 (oauth2.AuthFlowState = 5) then
  begin
    Memo1.Lines.Add('OAuth2 failed to complete.');
    Memo1.Lines.Add(oauth2.FailureInfo);
    Exit;
  end;

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

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

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

// Save the entire JSON response, which includes the access token, for future calls.
// The JSON AccessTokenResponse looks like this:
// {"access_token":"e6dqdG....mzjpT04w==","token_type":"Bearer","expires_in":2592000,"owner_id":984236}

fac := TCkFileAccess.Create(Self);
fac.WriteEntireTextFile('qa_data/tokens/geoop.json',oauth2.AccessTokenResponse,'utf-8',0);

Memo1.Lines.Add('Success.');
end;