Ruby metaprogramming inside model

开发者_开发百科

I have a model called Snippet, which contains snippets of HTML to push into views.

The model has a column CODE and another CONTENT

I'd like to write something like this in my view and get the content back

<%= raw Snippet.PHONE_NUMBER %> 

which looks up PHONE_NUMBER on CODE and returns CONTENT

---

Add a method_missing class method in Snippet class as follows

# Snippet class
class << self 
  def method_missing(method, *args, &block)
    if(snippet = Snippet.find_by_code(method.to_s))
      return snippet.content
    else
      return super(method, *args, &block)
    end
  end
end

This should do the trick.

However, on a related note, I'm not sure if doing this would be the best way to go because your code is dependent on the data in your database. Tomorrow, the record for phone number gets removed and your code Snippet.PHONE_NUMBER would break. There is a lot maintenance headache in this approach.

---

A cleaner approach (which would avoid metaprogramming) would have your view do something like this:

<%= snippet :PHONE_NUMBER %>

or

<%= snippet 'PHONE_NUMBER' %>

where the snippet method is defined in a helper module like this:

module SnippetHelper
  def snippet(code)
    raw Snippet.find_by_code(code.to_s).content
  end
end

and made available to all your views with something like this:

class ApplicationController < ApplicationController::Base
  helper :snippet
end

---

Or use delegate.

But it sounds like you're providing another implementation of partials, or helpers, or a combination of decent_exposure and some combination of helpers and partials.