Useful Rails 2.3 view helpers

application_helper.rb

# -*- encoding: utf-8 -*-

module ApplicationHelper
  def title(txt, show = true)
    content_for(:title) { h(txt.to_s) }
    @show_title = show

    show_title
  end

  def show_title?
    @show_title
  end

  def show_title(&block)
    if show_title?
      block_given? ? concat(capture(&block)) : yield_or(:title, '')
    end
  end

  def page_title
    yield_or(:title, I18n.t('application.defaults.title'))
  end

  def description(txt)
    content_for(:description) { h(txt.to_s) }
  end

  def page_description
    yield_or(:description, I18n.t('application.defaults.title'))
  end

  def header
    render :partial => 'shared/header'
  end

  def footer
    render :partial => 'shared/footer'
  end

  # Asynchronous Google Analytics snippet.
  # link: mathiasbynens.be/notes/async-analytics-snippet
  def google_analytics_snippet
    google_id = 'UA-XXXXX-X' # get from app preferences

    unless google_id.blank?
      snippet = [
        "var _gaq=[['_setAccount','#{google_id}'],['_trackPageview']]",
        "(function(d,t){var g=d.createElement(t),s=d.getElementsByTagName(t)[0]",
        "g.src=('https:'==location.protocol?'//ssl':'//www')+'.google-analytics.com/ga.js'",
        "s.parentNode.insertBefore(g,s)}(document,'script'))",
      ]

      javascript_tag { snippet.map { |line| "#{line};\n" }.reduce(:+) }
    end
  end

  # Get the value of a content_for block or fallback to the content
  # or block given
  # @link: http://stackoverflow.com/a/5238497
  def yield_or(name, content = nil, &block)
    ivar = "@content_for_#{name}"

    if instance_variable_defined?(ivar)
      content = instance_variable_get(ivar)
    else
      content = block_given? ? capture(&block) : content
    end

    block_given? ? concat(content) : content
  end

end