module ActionView
module Helpers
# Capture lets you extract parts of code into instance variables which
# can be used in other points of the template or even layout file.
#
# == Capturing a block into an instance variable
#
# <% @script = capture do %>
# [some html...]
# <% end %>
#
#
# == Add javascript to header using content_for
#
# content_for("name") is a wrapper for capture which will store the
# fragment in a instance variable similar to @content_for_layout.
#
# layout.rhtml:
#
#
#
# layout with js
#
#
#
# <%= @content_for_layout %>
#
#
#
# view.rhtml
#
# This page shows an alert box!
#
# <% content_for("script") do %>
# alert('hello world')
# <% end %>
#
# Normal view text
module CaptureHelper
# Capture allows you to extract a part of the template into an
# instance variable. You can use this instance variable anywhere
# in your templates and even in your layout.
#
# Example of capture being used in a .rhtml page:
#
# <% @greeting = capture do %>
# Welcome To my shiny new web page!
# <% end %>
#
# Example of capture being used in a .rxml page:
#
# @greeting = capture do
# 'Welcome To my shiny new web page!'
# end
def capture(*args, &block)
# execute the block
begin
buffer = eval("_erbout", block.binding)
rescue
buffer = nil
end
if buffer.nil?
capture_block(*args, &block)
else
capture_erb_with_buffer(buffer, *args, &block)
end
end
# Content_for will store the given block
# in an instance variable for later use in another template
# or in the layout.
#
# The name of the instance variable is content_for_
# to stay consistent with @content_for_layout which is used
# by ActionView's layouts
#
# Example:
#
# <% content_for("header") do %>
# alert('hello world')
# <% end %>
#
# You can use @content_for_header anywhere in your templates.
#
# NOTE: Beware that content_for is ignored in caches. So you shouldn't use it
# for elements that are going to be fragment cached.
def content_for(name, &block)
eval "@content_for_#{name} = (@content_for_#{name} || '') + capture(&block)"
end
private
def capture_block(*args, &block)
block.call(*args)
end
def capture_erb(*args, &block)
buffer = eval("_erbout", block.binding)
capture_erb_with_buffer(buffer, *args, &block)
end
def capture_erb_with_buffer(buffer, *args, &block)
pos = buffer.length
block.call(*args)
# extract the block
data = buffer[pos..-1]
# replace it in the original with empty string
buffer[pos..-1] = ''
data
end
def erb_content_for(name, &block)
eval "@content_for_#{name} = (@content_for_#{name} || '') + capture_erb(&block)"
end
def block_content_for(name, &block)
eval "@content_for_#{name} = (@content_for_#{name} || '') + capture_block(&block)"
end
end
end
end