questions about inheritance in Rails

rubyonrails-talk
1

Hi --

I am in the process of subclassing some things in a current Rails project and would like some feedback on how I'm approaching it... what I have works but I'm not sure if there is a better way to approach this. :slight_smile:

I am currently subclassing controllers like so:

class LookupsController < ApplicationController # GET /lookups def index end

#----------------------------------------------------------------- # the rest of these methods are called from subclassed controllers #-----------------------------------------------------------------

# GET /{controller_name} # GET /{controller_name}.xml def index_list    render 'lookups/index' and return if controller_name == 'lookups'    eval('@' + controller_name + ' = ' + model_name + '.find(:all)')    respond_to do |format|      format.html { render 'lookups/list' }      format.xml { render :xml => eval('@' + controller_name + '.to_xml') }    end end

This is all sort of at first glance, so I could well be overlooking some pitfalls, but why don't you just say @items or something instead of all the eval'ing? Also, instead of model_name, you could have your helper method return a model class. That way, you could do:

   @items = model.find(:all)

# ... and so on ... end

class StatesController < LookupsController def index    index_list end end

and the shared view template looks like this;

<h1><%= pretty_controller_name %></h1> <table> <thead> <tr>    <td id="col_actions">Actions</td>    <td id="col_name">Name</td> </tr> </thead> <tbody> <% for item in eval('@' + controller_name) %>    <tr class="<%= cycle("even","odd") %>">      <td> <span class="itemActions"> &nbsp;      <%= link_to(image_tag('item_delete.gif'),             eval(model_name + '_path(:id => item)'),

At the very least I would use send there:

   send("#{model_name}_path", :id => item)

But it's nicer if you can encapsulated that kind of calculation in the controller or a helper method.

I'll leave it at that, pending feedback on what I've missed :slight_smile:

David

2

Hi --

David wrote:

This is all sort of at first glance, so I could well be overlooking some pitfalls, but why don't you just say @items or something instead of all the eval'ing? Also, instead of model_name, you could have your helper method return a model class. That way, you could do:

   @items = model.find(:all)

Thanks... good point. :slight_smile: I was so focused on translating the existing code that I missed that.

At the very least I would use send there:

   send("#{model_name}_path", :id => item)

But it's nicer if you can encapsulated that kind of calculation in the controller or a helper method.

In other words, wrap the route method invocation with a helper method to simplify the view code?

Yes -- something like:

   def model_path(*args)      send("#{model_name}_path", *args)    end

at which point you could do:

   <%= link to "Click here", model_path :id => item %>

There may be yet further ways to simplify it all but initially at least I'd go for pushing all the low-level-ish stuff out of the views and see what happens.

(Punting on the JS question... :slight_smile:

David