Question

I’m just starting to tinker with extending the rails framework, and as an experiment, I thought I’d add some extra info inside the form_for helper. Specifically, when form_for is called, I’d like to generate an extra h1 tag such as:

# regular form_for <form> opening tag
<h1>Woohoo! It's added!</h1>
# tags fed into form_for via &proc
# form_for close <form> tag

At the moment I’ve added a /lib file that opens up ActiveRecord::FormHelper and overrides “form for”. Needless to say writing out the whole form_for method with just the one added line added is dog ugly…but I can’t call super() because, well, instead of inheriting from the method I’d like to super(), I’ve just overwritten it in /lib.

So, assuming I stubbornly want the functionality to be called via the same form_for tag (instead of, for example extended_form_for), what’s the standard way for calling back to the original form_for method I’m overwriting? alias_method_chain? Thought I’d ask before I cement in some potentially lousy practices. If any hardened veterans could give an example I’d be appreciative.

Cheers

Answer 1

alias_method_chain is by far the simplest way to overwrite the method while still being able to call the original method. So in your lib file you’ll want something like this:

def form_for_with_header(...)
  form_for_without_header(...)
  content_tag(:h1, "Header tag here")
  # etc...
end