instance method `content_for`

Ruby on Rails 3.0.20

Since v2.2.3

Available in: v2.2.3 v2.3.18 v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

content_for(name, content = nil, &block)

Calling content_for stores a block of markup in an identifier for later use. You can make subsequent calls to the stored content in other templates, helper modules or the layout by passing the identifier as an argument to content_for.

Note: yield can still be used to retrieve the stored content, but calling yield doesn’t work in helper modules, while content_for does.

Examples

<% content_for :not_authorized do %>
  alert('You are not authorized to do that!')
<% end %>

You can then use content_for :not_authorized anywhere in your templates.

<%= content_for :not_authorized if current_user.nil? %>

This is equivalent to:

<%= yield :not_authorized if current_user.nil? %>

content_for, however, can also be used in helper modules.

module StorageHelper
  def stored_content
    content_for(:storage) || "Your storage is empty"
  end
end

This helper works just like normal helpers.

<%= stored_content %>

You can use the yield syntax alongside an existing call to yield in a layout. For example:

<%# This is the layout %>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
  <title>My Website</title>
  <%= yield :script %>
</head>
<body>
  <%= yield %>
</body>
</html>

And now, we’ll create a view that has a content_for call that creates the script identifier.

<%# This is our view %>
Please login!

<% content_for :script do %>
  <script type="text/javascript">alert('You are not authorized to view this page!')</script>
<% end %>

Then, in another view, you could to do something like this:

<%= link_to 'Logout', :action => 'logout', :remote => true %>

<% content_for :script do %>
  <%= javascript_include_tag :defaults %>
<% end %>

That will place script tags for Prototype, Scriptaculous, and application.js (if it exists) on the page; this technique is useful if you’ll only be using these scripts in a few views.

Note that content_for concatenates the blocks it is given for a particular identifier in order. For example:

<% content_for :navigation do %>
  <li><%= link_to 'Home', :action => 'index' %></li>
<% end %>

<%#  Add some other content, or use a different template: %>

<% content_for :navigation do %>
  <li><%= link_to 'Login', :action => 'login' %></li>
<% end %>

Then, in another template or layout, this code would render both links in order:

<ul><%= content_for :navigation %></ul>

Lastly, simple content can be passed as a parameter:

<% content_for :script, javascript_include_tag(:defaults) %>

WARNING: content_for is ignored in caches. So you shouldn’t use it for elements that will be fragment cached.

Parameters

name req
content opt = nil
block block

Source

# File actionpack/lib/action_view/helpers/capture_helper.rb, line 136
      def content_for(name, content = nil, &block)
        content = capture(&block) if block_given?
        @_content_for[name] << content if content
        @_content_for[name] unless content
      end

Defined in actionpack/lib/action_view/helpers/capture_helper.rb line 136 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActionView::Helpers::CaptureHelper

Signature

Examples

Parameters