intraweb-framework

Intraweb Framework - Spec-Kit

Intraweb is a VCL-for-the-Web framework that allows you to create stateful business web applications in a semantic way similar to creating Desktop applications. When dealing with Intraweb in Copilot or your project, consider the following best practices to ensure maintainability and scalability.

1. Sessions (UserSession) and Global Variables

Golden Rule: Do not use classic unit var global variables or Singleton instances for user data, since Intraweb applications run in a Multithread environment with concurrent sessions (each user has their own).

• To maintain user-specific data, strictly use the UserSessionUnit.pas unit (ServerController.UserSession Instance).

//❌ BAD: Incorrect Usage (Global scope variable serves all sessions, Multithreading problem)
var
  LCustomerId: Integer;

//✅ GOOD: Correct Usage (Safe properties of the current context)
UserSession.CustomerId := 10;

2. ServerController and Configuration

The global system parameters, database connection pool and initializations that do not depend on the user must be resolved in the ServerController (IWServerController.pas) object. Avoid injecting heavy dependencies and direct database scopes in TIWAppForm.

3. Non-Blocking User Interfaces (Asynchronous Callbacks)

In the web context, you should not use blocking code to "wait" for the user, such as ShowMessage, InputBox, or classic VCL ModalResults calls that rely on code locking on the same line.

• Use the OnAsyncClick property for DOM updates without full-screen postback.
• In Intraweb version 15 or newer, explore the capabilities of WebApplication.ShowMessage combined with Ajax calls and safe web interface interrupts.

//❌ BAD: Blocking the thread on the Intraweb
procedure TIWForm1.iwBtnSaveClick(Sender: TObject);
begin
  if Application.MessageBox('Deseja salvar?', 'Confirme', MB_YESNO) = IDYES then
    //Rescue code
end;

//✅ GOOD: Using Ajax Async from Intraweb
procedure TIWForm1.iwBtnSaveAsyncClick(Sender: TObject; EventParams: TStringList);
begin
  WebApplication.ShowMessage('Registro Salvo via Callback Assíncrono!', smAlert);
end;