Giving a model attributes methods

Question

My Song model has a lyrics text attribute. Since new lines are \n-separated in my lyrics, I often find myself doing this in my views to make the lyrics HTML-friendly:

@song.lyrics.strip.gsub(/\n/, "\n<br />")

I'm repeating the gsub logic all over my application, and, worse still, I can't change the format in which I store my lyrics without touching everywhere I tried printing them as HTML.

I'd like to abstract this so that I can write this in my views:

@song.lyrics.to_html

So that the strip.gsub(/\n/, "\n<br />") logic is present in only one place in my application (in the to_html method).

What's the best way to do this?

Answer 1

If you need to use the exact @song.lyrics.to_html syntax and you don't want to create a Lyrics model, you can add a singleton method to the string returned by the lyrics method:

class Song
  def lyrics
    str = read_attribute(:lyrics)
    def str.to_html
      strip.gsub(/\n/, "\n<br />")
    end
    str
  end
end

However, this is not really a great design. For something more re-usable you might want to write a module with a to_html method like this:

module HtmlFormatter
  def to_html(attribute)
    send(attribute).strip.gsub(/\n/, "\n<br />")
  end
end

If you include HtmlFormatter in your Song model you can call the method like this:

@song.to_html(:lyrics)

So it doesn't follow your desired syntax exactly, but I think it's a better design.

You might also want to consider a separate Lyrics model which could have all kinds of features, but this might be too heavy for your application.

Answer 2

Since is a view-related issue, you can place your to_html method on the ApplicationHelper module

module ApplicationHelper

  def to_html(str)
    str.strip.gsub(/\n/, "\n<br />")
  end

end

so, on your views :

<% = to_html(@song.lyrics) %>