129 lines
3.8 KiB
Ruby
129 lines
3.8 KiB
Ruby
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module ActionView
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module Helpers
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# Capture lets you extract parts of code which
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# can be used in other points of the template or even layout file.
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#
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# == Capturing a block into an instance variable
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#
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# <% @script = capture do %>
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# [some html...]
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# <% end %>
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#
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# == Add javascript to header using content_for
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#
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# content_for("name") is a wrapper for capture which will
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# make the fragment available by name to a yielding layout or template.
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#
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# layout.rhtml:
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#
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# <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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# <head>
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# <title>layout with js</title>
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# <script type="text/javascript">
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# <%= yield :script %>
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# </script>
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# </head>
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# <body>
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# <%= yield %>
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# </body>
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# </html>
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#
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# view.rhtml
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#
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# This page shows an alert box!
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#
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# <% content_for("script") do %>
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# alert('hello world')
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# <% end %>
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#
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# Normal view text
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module CaptureHelper
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# Capture allows you to extract a part of the template into an
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# instance variable. You can use this instance variable anywhere
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# in your templates and even in your layout.
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#
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# Example of capture being used in a .rhtml page:
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#
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# <% @greeting = capture do %>
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# Welcome To my shiny new web page!
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# <% end %>
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#
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# Example of capture being used in a .rxml page:
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#
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# @greeting = capture do
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# 'Welcome To my shiny new web page!'
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# end
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def capture(*args, &block)
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# execute the block
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begin
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buffer = eval("_erbout", block.binding)
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rescue
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buffer = nil
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end
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if buffer.nil?
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capture_block(*args, &block)
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else
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capture_erb_with_buffer(buffer, *args, &block)
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end
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end
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# Calling content_for stores the block of markup for later use.
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# Subsequently, you can make calls to it by name with <tt>yield</tt>
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# in another template or in the layout.
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#
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# Example:
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#
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# <% content_for("header") do %>
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# alert('hello world')
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# <% end %>
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#
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# You can use yield :header anywhere in your templates.
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#
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# <%= yield :header %>
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#
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# NOTE: Beware that content_for is ignored in caches. So you shouldn't use it
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# for elements that are going to be fragment cached.
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#
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# The deprecated way of accessing a content_for block was to use a instance variable
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# named @@content_for_#{name_of_the_content_block}@. So <tt><%= content_for('footer') %></tt>
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# would be avaiable as <tt><%= @content_for_footer %></tt>. The preferred notation now is
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# <tt><%= yield :footer %></tt>.
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def content_for(name, &block)
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eval "@content_for_#{name} = (@content_for_#{name} || '') + capture(&block)"
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end
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private
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def capture_block(*args, &block)
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block.call(*args)
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end
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def capture_erb(*args, &block)
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buffer = eval("_erbout", block.binding)
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capture_erb_with_buffer(buffer, *args, &block)
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end
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def capture_erb_with_buffer(buffer, *args, &block)
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pos = buffer.length
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block.call(*args)
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# extract the block
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data = buffer[pos..-1]
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# replace it in the original with empty string
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buffer[pos..-1] = ''
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data
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end
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def erb_content_for(name, &block)
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eval "@content_for_#{name} = (@content_for_#{name} || '') + capture_erb(&block)"
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end
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def block_content_for(name, &block)
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eval "@content_for_#{name} = (@content_for_#{name} || '') + capture_block(&block)"
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end
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end
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end
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end
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