Pascal (Lazarus/Delphi)

Shopify OAuth2 Authentication

See more OAuth2 Examples

This example shows how to obtain an initial access token for a Shopify application using OAuth2 authentication specifically for non-web applications. This process requires displaying a browser window to secure user authorization. In contrast, web-based applications use a different method to obtain an OAuth2 token, as they redirect back to the application via a URL. Note: Once you have the access token, all subsequent Chilkat examples that rely on an already-obtained token are applicable to both web and non-web applications. 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.OAuth2,
  Chilkat.StringBuilder;

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

procedure RunDemo;
var
  success: Boolean;
  oauth2: TOAuth2;
  url: string;
  numMsWaited: Integer;
  sbJson: TStringBuilder;

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.
  //  Make sure that "http://localhost:3017/" is listed in your Whitelisted Redirection URLs for your Shopify app.
  oauth2.ListenPort := 3017;

  //  The full content of the Authorization Endpoin for Shopify looks like this:
  //  https://{shop}.myshopify.com/admin/oauth/authorize?client_id={api_key}&scope={scopes}&redirect_uri={redirect_uri}&state={nonce}&grant_options[]={option}

  //  Replace "chilkat" with your shop name.
  oauth2.AuthorizationEndpoint := 'https://chilkat.myshopify.com/admin/oauth/authorize';
  oauth2.TokenEndpoint := 'https://chilkat.myshopify.com/admin/oauth/access_token';

  //  Replace this with your actual API KEY (client ID)
  oauth2.ClientId := 'SHOPIFY_API_KEY';

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

  //  Set requested scopes.  See https://help.shopify.com/api/getting-started/authentication/oauth
  oauth2.Scope := 'read_product_listings,read_customers,read_orders,read_draft_orders';

  //  Begin the OAuth2 Authorization code 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);

  //  Save the full JSON access token response to a file.
  sbJson := TStringBuilder.Create;
  sbJson.Append(oauth2.AccessTokenResponse);
  sbJson.WriteFile('qa_data/tokens/shopify-access-token.json','utf-8',False);

  //  The saved JSON response looks like this:

  //  {
  //    "access_token": "1364e43a5332583188cb27bc85469b1f",
  //    "scope": "read_product_listings,read_customers,read_orders,read_draft_orders"
  //  }


  oauth2.Free;
  sbJson.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.