Rails - How can I detect if the content_for content was provided?

Question

I want to detect if content was provided for content_for tag in my template, and if not fall back to default value:

<title>
  <% if content_is_provided -%>
    <%= yield :title -%>
  <% else -%>
    404 - Page Unknown
  <% end -%>
</title>

Any easy way to detect this? I tried <% if :title -%> but that didn't do much. thanks.

Answer 1

You can streamline the code further:

def content_exists?(name)
  return instance_variable_get("@content_for_#{name}")
end

Answer 2

Try this:

<title>
  <%= yield :title || "404 - Page Unknown" -%>
</title>