Rails: Proper way to add functionality to rails methods

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

lest · Accepted Answer · 2012-03-25 19:13:43Z

5

You could override form_for in your ApplicationHelper:

module ApplicationHelper
  def form_for(*)
    content_tag(:h1, "Woohoo! It's added!") + super
  end
end

answered Mar 25, 2012 at 19:13

lest

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Comments

Niklas B. · Accepted Answer · 2012-03-25 19:11:32Z

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

edited Mar 25, 2012 at 19:11

Niklas B.

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answered Mar 25, 2012 at 19:04

Shaun

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1 Comment

Vasiliy Ermolovich Over a year ago

I think @lest's answer is more rails way

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