Where does the meta content live in the MVC?

Question

I've been thinking about meta content in MVC, specifically the page title and the meta description (which is useful for guiding the snippet Google shows on your search result).

I can't come to a firm decision about where this should live though. There's often a little bit of logic around it depending (for a UGC application) on how readers have interacted with the content.

I can't decide whether this meta content is better constructed in the view layer or the controller. It almost certainly doesn't live in the model since it is specific to a particular view of the data however while my first instinct was to put it in the view I feel that it might be better abstracted.

I'm interested in what approach other people have taken.

Answer 1

Meta content is typically set using helpers, content_for and yield.

For instance:

# app/helpers/application_helper.rb
def title(title)
  content_for :title, title
end

def description(description)
  content_for :description, description
end

# app/views/layouts/application.html.erb
<title>My app <%= yield :title %></title>
<meta name="description"><%= yield :description %></meta>

# app/views/some_controller/some_action.html.erb
<%
title @an_instance.an_attribute # or whatever you want by the way
description @an_instance.another_attribute
%>

If you intend to do streaming, you should use provide instead of content_for in your helpers.

Never ever put an instance variable in your controller that is used for meta content (such as @title = 'blabla'; @description = 'blablabla')

Here are some resources that do the same (list non-exhaustive):

• BUILDING BULLETPROOF VIEWS (the slides are downloadable)
• Rails Best Practices (commercial)