Options processing

The dashboard already looks great.

The widgets need customized titles, though. Being all about encapsulation, Apotomo naturally provides a way to pass options into widgets from outside.

   has_widgets do |root|
     root << widget(:twitter_widget, 'parrot', :display_form)
     root << widget(:trashbin_widget, 'bin', :display, :title => "Trash tweets here!")
   end

We can provide arbitrary options in the widget method (line 6).

 class TrashbinWidget < Apotomo::Widget
   responds_to_event :drop, :with => :trash
   
   def display
     setup!
     
     render :layout => 'portlet'
   end
   
  def trash
    setup!
    
    Tweet.find(params[:id]).delete
    trigger :tweetDeleted
    
    update :view => :display
  end
  
private
  def setup!
    @title = @opts[:title]
  end
end

The widget can subsequently access the @opts hash and process its parameters (line 21). It also uses params to access request parameters (line 13). You may use these variables, however, there is a safer approach in Apotomo that we'll discuss shortly.

Note that we have to call setup! in the start state as well as in the trigger states, as our widget is stateless.

Using hooks

Fortunately, Apotomo already has a hook for exactly that job.

 class TrashbinWidget < Apotomo::Widget
   responds_to_event :drop, :with => :trash
   
   after_initialize :setup!
   
   def display
     render :layout => 'portlet'
   end
   
  def trash
    Tweet.find(param(:id)).delete
    trigger :tweetDeleted
    
    update :view => :display
  end
  
private
  def setup!(*)
    @title = param(:title)
  end
end

The after_initialize hook (line 4) will execute all attached callbacks after the widget was created. It is somehow comparable to a before_filter in Rails controllers.

A cleaner parameter lookup

It is usually safer to use param for parameter access. This method provides both request parameters and variables from widget (line 11 and 19), where the latter overwrites parameters from the request in a name clash.

Apotomo is a Nick Sutterer product.