Brian's Waste of Time

Great article on the comparison of Struts and Rails. 
I have a few pointers on how you can make it even better.

1. Rename app/views/layout/scaffold.rb to app/views/layout/application.rb -- 
then its automatically picked up by all controllers.

2. Using model :user is not necessary unless you don't follow the 
User => user.rb model. When you do (and the generators ensure that you do 
pretty much all the time), the User model is automatically included when the 
class is referenced.

3. These are not necessary: helper_attr :return_to, :user_login. All instance 
variables assigned in a controller action is automatically made available to the view.

I'm not sure what the pass_thru is about, but in any case, here's a more idiomatic 
Rails controller for your example:

class LoginController < ApplicationController
  def index
    if @session['user'] = User.authenticate(@params['user_login'])
      logger.info "User logged in: #{@session['user']}"
      redirect_to_path(@params['return_to'])
    else
      @session['return_to'] = @params['return_to']
      redirect_to :controller => 'rsvp',
                  :action => 'select_invitation',
                  :params => { 'name' => @params['user_login'] }
    end
  end

  def pass_thru
    @return_to = @params['return_to']
    render_action 'login'
  end

  def logout
    reset_session
    redirect_to :controller => 'information', :action => 'index'
  end
end
--
David Heinemeier Hansson

/*
 * Copyright 2000-2004 Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.struts.webapp.example;

/* imports omitted */

/**
 * Validate a user logon.
 */
public final class LogonAction extends BaseAction {

    static String USERNAME = "username";
    static String PASSWORD = "password";

    User getUser(UserDatabase database, String username,
                           String password, ActionMessages errors) 
            throws ExpiredPasswordException {
        User user = null;
        if (database == null){
            errors.add(
                ActionMessages.GLOBAL_MESSAGE,
                new ActionMessage("error.database.missing"));
        }
        else {
            user = database.findUser(username);
            if ((user != null) && !user.getPassword().equals(password)) {
                user = null;
            }
            if (user == null) {
                errors.add(
                    ActionMessages.GLOBAL_MESSAGE,
                    new ActionMessage("error.password.mismatch"));
            }
        }
        return user;
    }

    void SaveUser(HttpServletRequest request, User user) {

        HttpSession session = request.getSession();
        session.setAttribute(Constants.USER_KEY, user);
        if (log.isDebugEnabled()) {
            log.debug(
                "LogonAction: User '"
                    + user.getUsername()
                    + "' logged on in session "
                    + session.getId());
        }
    }

    public ActionForward execute(
        ActionMapping mapping,
        ActionForm form,
        HttpServletRequest request,
        HttpServletResponse response)
        throws Exception {

        // Local variables
        UserDatabase database = getUserDatabase(request);
        String username = (String) PropertyUtils.getSimpleProperty(form,
                USERNAME);
        String password = (String) PropertyUtils.getSimpleProperty(form,
                PASSWORD);
        ActionMessages errors = new ActionMessages();

        // Retrieve user
        User user = getUser(database,username,password,errors);

        // Save (or clear) user object
        SaveUser(request,user);

        // Report back any errors, and exit if any
        if (!errors.isEmpty()) {
            this.saveErrors(request, errors);
            return (mapping.getInputForward());
        }

        // Otherwise, return "success"
        return (findSuccess(mapping));
    }
}

class LoginController < ApplicationController
  layout 'scaffold'
  model :user
  helper_attr :return_to, :user_login

  def index
    redirect_to :action => 'login'
  end

  def pass_thru
    @return_to = @params['return_to']
    render_action 'login'
  end

  def login
    @user_login = @params['user_login']
    @return_to = @params['return_to']
    
    valid_user = User.authenticate(@user_login)
    if (valid_user)
      logger.info("user logged in: #{valid_user}")
      @session['user'] = valid
      redirect_to_path @return_to
    else
      @session['return_to'] = @return_to
      redirect_to :controller => 'rsvp', 
                  :action => 'select_invitation',   
                  :params => { 'name' => @params['user_login'] }
    end
  end

  def logout
    reset_session
    redirect_to :controller => 'information', :action => 'index'
  end
end

render_action 'login'

brianm@kite:~/Sites/wedding/app$ tree views/
views/
|-- gift
|   |-- _gift_table.rhtml
|   |-- edit.rhtml
|   |-- list.rhtml
|   |-- new.rhtml
|   `-- show.rhtml
|-- information
|   |-- gardens.rhtml
|   |-- index.rhtml
|   |-- museum.rhtml
|   `-- reception.rhtml
|-- layouts
|   `-- scaffold.rhtml
|-- login
|   |-- login.rhtml
|   |-- logout.rhtml
|   `-- register.rhtml
`-- rsvp
    |-- index.rhtml
    |-- register.rhtml
    |-- select_invitation.rhtml
    |-- thank_you.rhtml
    |-- unlisted.rhtml
    `-- verify_invitation.rhtml

5 directories, 19 files
brianm@kite:~/Sites/wedding/app$ 

      redirect_to :controller => 'rsvp', 
                  :action => 'select_invitation',   
                  :params => { 'name' => @params['user_login'] }

layout 'scaffold'
model :user
helper_attr :return_to, :user_password, :user_login