module Webgen::ContentProcessor::HtmlHead

General information¶ ↑

Inserts additional links to CSS/JS files and other HTML head meta info directly before the HTML head end tag.

The data used by this content processor is taken from the Context object. Therefore this processor should be the last in the processing pipeline so that all other processors have been able to set the data.

Use the methods defined on the special Webgen::Context::HtmlHead::Proxy object which can be accessed via Webgen::Context::HtmlHead#html_head to provide values.

Internal details¶ ↑

The key :cp_html_head of context.persistent is used (the normal context.options won't do because the data needs to be shared 'backwards' during the rendering) and it has to be a Hash with the following values:

:js_file: An array of already resolved relative or absolute paths to Javascript files.
:js_inline: An array of Javascript fragments to be inserted directly into the head section.
:css_file: An array of already resolved relative or absolute paths to CSS files.
:css_inline: An array of CSS fragments to be inserted directly into the head section.
:meta: A hash with key-value pairs from which 'meta' tags are generated. The keys and the values will be properly escaped before insertion. The entries in the meta information 'meta' of the content node are also used and take precedence over these entries.

Duplicate values will be removed from the above mentioned arrays before generating the output.

Public Class Methods

call(context) click to toggle source

Insert the additional header information.

# File lib/webgen/content_processor/html_head.rb, line 40
def self.call(context)
  context.content.sub!(HTML_HEAD_END_RE) do |match|
    result = ''
    result << tags_from_context_data(context)
    result << links_to_translations(context)
    result << links_from_link_meta_info(context)
    result << match
  end
  context
end

links_from_link_meta_info(context) click to toggle source

Return a string containing HTML link tags to the links from the 'link' meta information.

# File lib/webgen/content_processor/html_head.rb, line 120
def self.links_from_link_meta_info(context)
  link_mi = Marshal.load(Marshal.dump(context.content_node['link'] || {}))
  result = ''

  # Add user defined javascript and CSS links
  resolve_paths(context, link_mi.delete('javascript')).each do |file|
    result += "\n<script type=\"text/javascript\" src=\"#{file}\"></script>"
  end
  resolve_paths(context, link_mi.delete('css')).each do |file|
    result += "\n<link rel=\"stylesheet\" href=\"#{file}\" type=\"text/css\" />"
  end

  # add generic links
  link_mi.sort.each do |link_type, vals|
    link_type = link_type.downcase
    [vals].flatten.each do |val|
      val = {'href' => val} if val.kind_of?(String)
      val['rel'] ||= link_type
      val = LINK_DOCUMENT_ATTRS.merge(val) if LINK_DOCUMENT_TYPES.include?(link_type)
      href = val.delete('href')
      href = resolve_paths(context, href).first if href
      if href
        result << "\n<link href=\"#{href}\" "
        val.sort.each {|k,v| result << "#{k}=\"#{ERB::Util.h(v)}\" "}
        result << "/>"
      else
        context.website.logger.error do
          "No link target specified for link type '#{link_type}' in 'link' meta information in <#{context.content_node}>"
        end
      end
    end
  end

  result
end

links_to_translations(context) click to toggle source

Return a string containing HTML link tags to translations of the destination node.

# File lib/webgen/content_processor/html_head.rb, line 87
def self.links_to_translations(context)
  context.website.tree.translations(context.dest_node).map do |node|
    next '' if node.alcn == context.dest_node.alcn
    context.website.ext.item_tracker.add(context.dest_node, :node_meta_info, node)

    result = "\n<link type=\"text/html\" rel=\"alternate\" hreflang=\"#{node.lang}\" "
    result << "href=\"#{context.dest_node.route_to(node)}\" "
    if node['title'] && !node['title'].empty?
      result << "lang=\"#{node.lang}\" title=\"#{ERB::Util.h(node['title'])}\" "
    end
    result << "/>"
  end.join('')
end

process_data_array(context, array_name, &block) click to toggle source

Yield the values of the specified array.

# File lib/webgen/content_processor/html_head.rb, line 82
def self.process_data_array(context, array_name, &block)
  (context.persistent[:cp_html_head][array_name] || []).uniq.each(&block)
end

resolve_paths(context, paths) click to toggle source

Given an array of path names, add tracker information for the resolved nodes (reference node is the content node) and return the relative paths to them.

# File lib/webgen/content_processor/html_head.rb, line 103
def self.resolve_paths(context, paths)
  [paths].flatten.compact.collect do |path|
    next path if Webgen::Path.url(path, false).absolute?
    node = context.content_node.resolve(path, context.dest_node.lang, true)
    if node
      context.website.ext.item_tracker.add(context.dest_node, :node_meta_info, node)
      context.dest_node.route_to(node)
    else
      nil
    end
  end.compact
end

tags_from_context_data(context) click to toggle source

Return a string containing the HTML tags corresponding to the information set in the given Context object and the values of the meta info key meta of the content node.

# File lib/webgen/content_processor/html_head.rb, line 53
def self.tags_from_context_data(context)
  result = ''
  if context.persistent[:cp_html_head].kind_of?(Hash)
    process_data_array(context, :js_file) do |js_file|
      result += "\n<script type=\"text/javascript\" src=\"#{js_file}\"></script>"
    end

    process_data_array(context, :js_inline) do |content|
      result += "\n<script type=\"text/javascript\">//<![CDATA[\n#{content}\n//]]></script>"
    end

    process_data_array(context, :css_file) do |css_file|
      result += "\n<link rel=\"stylesheet\" href=\"#{css_file}\" type=\"text/css\"/>"
    end

    process_data_array(context, :css_inline) do |content|
      result += "\n<style type=\"text/css\">/*<![CDATA[/*/\n#{content}\n/*]]>*/</style>"
    end
  end
  ((context.persistent[:cp_html_head] || {})[:meta] || {}).merge(context.content_node['meta'] || {}).each do |name, content|
    result += "\n<meta name=\"#{ERB::Util.h(name)}\" content=\"#{ERB::Util.h(content)}\" />"
  end
  ((context.persistent[:cp_html_head] || {})[:meta_property] || {}).merge(context.content_node['meta_property'] || {}).each do |property, content|
    result += "\n<meta property=\"#{ERB::Util.h(property)}\" content=\"#{ERB::Util.h(content)}\" />"
  end
  result
end