Pascal (Lazarus/Delphi)

GetHarvest API V2 OAuth Token

See more GetHarvest Examples

Demonstrates how to get an OAuth2 access token for the GetHarvest v2 API (from a desktop application). 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;

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

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

begin
  success := False;

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

  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;

  oauth2.AuthorizationEndpoint := 'https://id.getharvest.com/oauth2/authorize';
  oauth2.TokenEndpoint := 'https://id.getharvest.com/api/v2/oauth2/token';

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

  oauth2.CodeChallenge := False;

  oauth2.Scope := 'all';

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

  //  Launch the system's default browser navigated to the URL.
  success := oauth2.LaunchBrowser(url);
  if (success = False) then
    begin
      WriteLn(oauth2.LastErrorText);
      Exit;
    end;

  //  Now wait for the authorization.
  //  We'll wait for a max of 60 seconds.
  numMsWaited := 0;
  while (numMsWaited < 60000) 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();
      WriteLn('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
      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);

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

  //  The JSON response looks like this:

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


  oauth2.Free;
  json.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.