+++ /dev/null
-module ActionView
- module Helpers
- # CaptureHelper exposes methods to let you extract generated markup which
- # can be used in other parts of a template or layout file.
- # It provides a method to capture blocks into variables through capture and
- # a way to capture a block of markup for use in a layout through content_for.
- module CaptureHelper
- # The capture method allows you to extract part of a template into a
- # variable. You can then use this variable anywhere in your templates or layout.
- #
- # ==== Examples
- # The capture method can be used in ERb templates...
- #
- # <% @greeting = capture do %>
- # Welcome to my shiny new web page! The date and time is
- # <%= Time.now %>
- # <% end %>
- #
- # ...and Builder (RXML) templates.
- #
- # @timestamp = capture do
- # "The current timestamp is #{Time.now}."
- # end
- #
- # You can then use that variable anywhere else. For example:
- #
- # <html>
- # <head><title><%= @greeting %></title></head>
- # <body>
- # <b><%= @greeting %></b>
- # </body></html>
- #
- def capture(*args, &block)
- # Return captured buffer in erb.
- if block_called_from_erb?(block)
- with_output_buffer { block.call(*args) }
- else
- # Return block result otherwise, but protect buffer also.
- with_output_buffer { return block.call(*args) }
- end
- end
-
- # 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 or the layout
- # by passing the identifier as an argument to <tt>yield</tt>.
- #
- # ==== Examples
- #
- # <% content_for :not_authorized do %>
- # alert('You are not authorized to do that!')
- # <% end %>
- #
- # You can then use <tt>yield :not_authorized</tt> anywhere in your templates.
- #
- # <%= yield :not_authorized if current_user.nil? %>
- #
- # You can also use this syntax alongside an existing call to <tt>yield</tt> 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 <tt>script</tt> 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_remote 'Logout', :action => 'logout' %>
- #
- # <% 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><%= yield :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.
- #
- # The deprecated way of accessing a content_for block is to use an instance variable
- # named <tt>@content_for_#{name_of_the_content_block}</tt>. The preferred usage is now
- # <tt><%= yield :footer %></tt>.
- def content_for(name, content = nil, &block)
- ivar = "@content_for_#{name}"
- content = capture(&block) if block_given?
- instance_variable_set(ivar, "#{instance_variable_get(ivar)}#{content}")
- nil
- end
-
- # Use an alternate output buffer for the duration of the block.
- # Defaults to a new empty string.
- def with_output_buffer(buf = '') #:nodoc:
- self.output_buffer, old_buffer = buf, output_buffer
- yield
- output_buffer
- ensure
- self.output_buffer = old_buffer
- end
- end
- end
-end
projects / feedcatcher.git / blobdiff