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With the comet server APE it’s easy to create a web chat for your rails app. In the following howto you’ll find out how to use the user data of your rails app with restful_authentication also for your new chat. The javascript chat client will look like this demo.

Dependencies: installed APE-Server, ready rails app with restful_authentication using mysql

Scenario: You want to create a simple web chat for your rails app. Only logged in users should be able to use the chat using their name found in the mysql database.

Step 1 – Creating the APE server module

Because we’re using restful_authentication as authentication method, our server module has to have the ability to encrypt the password on its own. With this encrypt function, the module is able to validate the user and password.

First of all we need the individual encryption data from your rails app. So check /railsapp/config/initializers/site_keys.rb for the REST_AUTH_SITE_KEY and REST_AUTH_DIGEST_STRETCHES, e.g.:

REST_AUTH_SITE_KEY         = 'fecaf1261215db131593926217ddcb80191fd7e2'
REST_AUTH_DIGEST_STRETCHES = 10

Now get the server module example made by me and replace the rest_auth-variables with your individual site key and digest stretches. Also edit the mysql user, password and database of your rails environment. Put the easychat.js module in your /var/ape/examples directory and replace nickname.js with easychat.js in your /var/ape/main.ape.js file. Restart aped.

Note: In the authentication process we don’t give the raw password to APE for more security. We encrypt the already encrypted password with the restful_auth-mechanism. Our module is able to decrypt this double encrypted password and compare the encrypted passwords given by the client with the encrypted password in the user database.

Step 2 – Creating a rails controller and a view for the chat

Let’s generate a rails controller and a view for the chat:

./script/generate controller chat index

For the view we need the ape-jsf and javascript chat client. Put the ape-jsf-folder in /railsapp/public, this will make the framework reachable via http://yoursite.com/ape-jsf. We use the demo chat client found in /public/ape-jsf/Demos/Chat with a slight modification for our authentication process. Make a copy of this folder in /public/ape-jsf/Demos/easyChat and overwrite the demo.js with this modified version. Don’t forget to edit your /public/ape-jsf/Demos/config.js to make it fit your domain name.

Now we’re almost done. What we need is a controller and a view, where the user data is given to the ape and the chat client is loaded.
Replace your chat_controller.rb with this modified one. And the index.html.erb view with this modified version.

Step 3 – Chat!

Restart your APE server and rails environment. Now logged in users are able to chat via http://site.com/chat
This is a very basic setup with some problems (e.g. when connecting with a bad session id, the chat client can’t handle it, etc.). But I hope it’s a good starting point for your chat application.

Have fun chatting!

Filed under: APE, Blog, English, Ruby On Rails on Januar 6th, 2010 | 1 Comment »

For the most applications I’m developing I want the users to be able to edit their user data or profile using model mass assignment in Rails.  Moreover I want additionally an easy administration panel for super users who can access all the attributes of the users (and nested attributes) via mass assignment.

Now what’s an easy and rails-like way to allow users and super users to edit exclusively the attributes they have access for? I’ve searched the web and found dirty solutions like accessing the current_user from your model or modifying before_*-handlers. So here is my way.

In the user-model I declare the attributes the user has access to, using attr_accessible:

class User < ActiveRecord::Base
  attr_accessible :login, :email, :birthday, :country, :city, :age_is_public
end

For the administration panel I create a new model which extends the User model. This AdminUser model extends the accessible attributes of the User model for the super user.

class AdminUser < User
  attr_accessible :role, :comment, :level
end

Now I access the User model from the controller for standard users and the AdminUser model from the admin controller.  The verification for a valid and logged in super user is done there.

class UsersController < ApplicationController
  before_filter :login_required
  [..]
  def update
    @user = User.find(current_user.id)
    @user.update_attributes(params[:user])
  [..]
end

class AdminUsersController < ApplicationController
  before_filter :login_required, :admin_required
  [..]

  def update
    @user = AdminUser.find(params[:id])
    @user.update_attributes(params[:user])
  [..]
end

That's it. Nice and clean model mass assignment depending on the security level of the user. This also works nice with nested attributes. Don't forget to add _attributes to your symbol name in attr_accessible in this case (like  :profile_attributes for a has_one relationship with the profile model).

Keywords: admin panel, control panel, rails, nested_attributes_for, mass assignment, attr_accessible, attr_protected

Filed under: Development, English, Ruby On Rails on Juni 18th, 2009 | 1 Comment »

After upgrading to Rails 2.3.2 I’ve tried to run the testcases. The following error occured:

test/test_helper.rb:22: undefined method `use_transactional_fixtures=’ for Test::Unit::TestCase:Class (NoMethodError)

Solution:

Test::Unit::TestCase changed to ActiveSupport::TestCase, so simply edit your test/test_helper and change the name of the class.

Keywords: functional test problems

Filed under: English, Ruby On Rails on April 29th, 2009 | 2 Comments »

The flickering bug described in the following was fixed. If you don’t want to wait until it has been released officially, get the deb packages at launchpad:

https://launchpad.net/~tormodvolden/+archive/ppa

After installing you should be able to use the driver with the default EXA acceleration method again. If you’ve changed anything at the xorg.conf to avoid the flickering, don’t forget to reset your xorg.conf after installing the fixed driver.

For the sake of completeness, here is the old workaround:

When I had installed the new Ubuntu release on my notebook (HP Compaq 6715b), I was so happy about the fact, that most problems which had occured with the notebook drivers finally disappeared in Jaunty. But that feeling didn’t last long.

Broadcom WLAN-Chip with WPA2 worked – YAY!, Standby and Hibernation worked – YAY!

But, what’s that? Flickering black and red stripes around the middle of the screen, flashing white stripes and more flickering when scrolling the terminal. OpenGL apps also flicker and display the windows behind the OpenGL window for a split second now and then.

Unfortunately ATI moved the drivers for the graphic chipset ATI Xpress 1250 to their “Legacy” program.  They discontinued their proprietary driver support several months ago. BOOOO!! Tragically Jaunty comes with the new Xorg 7.4, which is NOT supported by this legacy driver.  NO!

Sadly x1250 users have to use the free radeon driver coming with ubuntu.

Ok, let’s set it up to remove the flickering and display problems!

1. Turn off Compiz completely (System -> Settings -> Appearance -> Visual Effects). This will remove the first problems.
2. Change the “Accelleration Method” from EXA to XAA.  Edit your /etc/X11/xorg.conf and add the following line to your Device section:
   Option “AccelMethod” “XAA”
   This will remove the rest of the display problems.
3. Restart Gnome in a clean way. First logout in Gnome, then Switch with Ctrl+Alt+F1 to a shell and do a sudo /etc/init.d/gdm restart
4. Problems should be gone now

I couldn’t figure out any difference in perfomance after switching the AccelMethod to XAA. But neither EXA nor XAA can’t control the x1250 chipset as the proprietary driver of ATI did. It’s pretty slow and it seems that the free driver handles the chipset not correctly, because the system temperature is higher now and the notebook fan is nearly always activated.

I hope now, that there will be a better free driver of this chipset soon. And I also hope, that I could help you a little bit in how to get rid of the display problems with the free graphic driver radeon and the x1250 chipset.

Any new ideas or news are welcome!

Keywords: flickering, red black, display problems, X1250, Xpress1250, ATI, white stripes, compiz, desktop effects

Filed under: English, Rails 2.1, Ubuntu on April 28th, 2009 | 3 Comments »

I’m using the following snippet in my mouseMoved-Event to handle the switching between the windows os mouse cursor and the cegui mouse cursor when entering/leaving the RenderWindow.

      if (mMouseInWindow)
      {
        CEGUI::System::getSingleton().injectMousePosition( arg.state.X.abs, arg.state.Y.abs );
        if (arg.state.X.abs == 0 || arg.state.Y.abs == 0 ||
            arg.state.X.abs == mWindowMaxWidth || arg.state.Y.abs == mWindowMaxHeight)
        {
          CEGUI::MouseCursor::getSingleton().hide();
          ShowCursor(true); // windows only
          mMouseInWindow = false;
        }
      }
      else if (arg.state.X.abs > 0 && arg.state.Y.abs > 0 &&
        arg.state.X.abs < mWindowMaxWidth && arg.state.Y.abs < mWindowMaxHeight)
      {
        CEGUI::MouseCursor::getSingleton().show();
        ShowCursor(false); // windows only
        mMouseInWindow = true;
      }

Filed under: CEGUI, OIS on Januar 18th, 2009 | No Comments »