vendor/rails/actionpack/lib/action_view/helpers/atom_feed_helper.rb

   1 require 'set'
   2
   3 # Adds easy defaults to writing Atom feeds with the Builder template engine (this does not work on ERb or any other
   4 # template languages).
   5 module ActionView
   6   module Helpers #:nodoc:
   7     module AtomFeedHelper
   8       # Full usage example:
   9       #
  10       #   config/routes.rb:
  11       #     ActionController::Routing::Routes.draw do |map|
  12       #       map.resources :posts
  13       #       map.root :controller => "posts"
  14       #     end
  15       #
  16       #   app/controllers/posts_controller.rb:
  17       #     class PostsController < ApplicationController::Base
  18       #       # GET /posts.html
  19       #       # GET /posts.atom
  20       #       def index
  21       #         @posts = Post.find(:all)
  22       #
  23       #         respond_to do |format|
  24       #           format.html
  25       #           format.atom
  26       #         end
  27       #       end
  28       #     end
  29       #
  30       #   app/views/posts/index.atom.builder:
  31       #     atom_feed do |feed|
  32       #       feed.title("My great blog!")
  33       #       feed.updated((@posts.first.created_at))
  34       #
  35       #       for post in @posts
  36       #         feed.entry(post) do |entry|
  37       #           entry.title(post.title)
  38       #           entry.content(post.body, :type => 'html')
  39       #
  40       #           entry.author do |author|
  41       #             author.name("DHH")
  42       #           end
  43       #         end
  44       #       end
  45       #     end
  46       #
  47       # The options for atom_feed are:
  48       #
  49       # * <tt>:language</tt>: Defaults to "en-US".
  50       # * <tt>:root_url</tt>: The HTML alternative that this feed is doubling for. Defaults to / on the current host.
  51       # * <tt>:url</tt>: The URL for this feed. Defaults to the current URL.
  52       # * <tt>:id</tt>: The id for this feed. Defaults to "tag:#{request.host},#{options[:schema_date]}:#{request.request_uri.split(".")[0]}"
  53       # * <tt>:schema_date</tt>: The date at which the tag scheme for the feed was first used. A good default is the year you
  54       #   created the feed. See http://feedvalidator.org/docs/error/InvalidTAG.html for more information. If not specified,
  55       #   2005 is used (as an "I don't care" value).
  56       # * <tt>:instruct</tt>: Hash of XML processing instructions in the form {target => {attribute => value, }} or {target => [{attribute => value, }, ]}
  57       #
  58       # Other namespaces can be added to the root element:
  59       #
  60       #   app/views/posts/index.atom.builder:
  61       #     atom_feed({'xmlns:app' => 'http://www.w3.org/2007/app',
  62       #         'xmlns:openSearch' => 'http://a9.com/-/spec/opensearch/1.1/'}) do |feed|
  63       #       feed.title("My great blog!")
  64       #       feed.updated((@posts.first.created_at))
  65       #       feed.tag!(openSearch:totalResults, 10)
  66       #
  67       #       for post in @posts
  68       #         feed.entry(post) do |entry|
  69       #           entry.title(post.title)
  70       #           entry.content(post.body, :type => 'html')
  71       #           entry.tag!('app:edited', Time.now)
  72       #
  73       #           entry.author do |author|
  74       #             author.name("DHH")
  75       #           end
  76       #         end
  77       #       end
  78       #     end
  79       #
  80       # The Atom spec defines five elements (content rights title subtitle
  81       # summary) which may directly contain xhtml content if :type => 'xhtml'
  82       # is specified as an attribute.  If so, this helper will take care of
  83       # the enclosing div and xhtml namespace declaration.  Example usage:
  84       #
  85       #    entry.summary :type => 'xhtml' do |xhtml|
  86       #      xhtml.p pluralize(order.line_items.count, "line item")
  87       #      xhtml.p "Shipped to #{order.address}"
  88       #      xhtml.p "Paid by #{order.pay_type}"
  89       #    end
  90       #
  91       #
  92       # atom_feed yields an AtomFeedBuilder instance.  Nested elements yield
  93       # an AtomBuilder instance.
  94       def atom_feed(options = {}, &block)
  95         if options[:schema_date]
  96           options[:schema_date] = options[:schema_date].strftime("%Y-%m-%d") if options[:schema_date].respond_to?(:strftime)
  97         else
  98           options[:schema_date] = "2005" # The Atom spec copyright date
  99         end
 100
 101         xml = options[:xml] || eval("xml", block.binding)
 102         xml.instruct!
 103         if options[:instruct]
 104           options[:instruct].each do |target,attrs|
 105             if attrs.respond_to?(:keys)
 106               xml.instruct!(target, attrs)
 107             elsif attrs.respond_to?(:each)
 108               attrs.each { |attr_group| xml.instruct!(target, attr_group) }
 109             end
 110           end
 111         end
 112
 113         feed_opts = {"xml:lang" => options[:language] || "en-US", "xmlns" => 'http://www.w3.org/2005/Atom'}
 114         feed_opts.merge!(options).reject!{|k,v| !k.to_s.match(/^xml/)}
 115
 116         xml.feed(feed_opts) do
 117           xml.id(options[:id] || "tag:#{request.host},#{options[:schema_date]}:#{request.request_uri.split(".")[0]}")
 118           xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:root_url] || (request.protocol + request.host_with_port))
 119           xml.link(:rel => 'self', :type => 'application/atom+xml', :href => options[:url] || request.url)
 120
 121           yield AtomFeedBuilder.new(xml, self, options)
 122         end
 123       end
 124
 125       class AtomBuilder
 126         XHTML_TAG_NAMES = %w(content rights title subtitle summary).to_set
 127
 128         def initialize(xml)
 129           @xml = xml
 130         end
 131
 132         private
 133           # Delegate to xml builder, first wrapping the element in a xhtml
 134           # namespaced div element if the method and arguments indicate
 135           # that an xhtml_block? is desired.
 136           def method_missing(method, *arguments, &block)
 137             if xhtml_block?(method, arguments)
 138               @xml.__send__(method, *arguments) do
 139                 @xml.div(:xmlns => 'http://www.w3.org/1999/xhtml') do |xhtml|
 140                   block.call(xhtml)
 141                 end
 142               end
 143             else
 144               @xml.__send__(method, *arguments, &block)
 145             end
 146           end
 147
 148           # True if the method name matches one of the five elements defined
 149           # in the Atom spec as potentially containing XHTML content and
 150           # if :type => 'xhtml' is, in fact, specified.
 151           def xhtml_block?(method, arguments)
 152             if XHTML_TAG_NAMES.include?(method.to_s)
 153               last = arguments.last
 154               last.is_a?(Hash) && last[:type].to_s == 'xhtml'
 155             end
 156           end
 157       end
 158
 159       class AtomFeedBuilder < AtomBuilder
 160         def initialize(xml, view, feed_options = {})
 161           @xml, @view, @feed_options = xml, view, feed_options
 162         end
 163
 164         # Accepts a Date or Time object and inserts it in the proper format. If nil is passed, current time in UTC is used.
 165         def updated(date_or_time = nil)
 166           @xml.updated((date_or_time || Time.now.utc).xmlschema)
 167         end
 168
 169         # Creates an entry tag for a specific record and prefills the id using class and id.
 170         #
 171         # Options:
 172         #
 173         # * <tt>:published</tt>: Time first published. Defaults to the created_at attribute on the record if one such exists.
 174         # * <tt>:updated</tt>: Time of update. Defaults to the updated_at attribute on the record if one such exists.
 175         # * <tt>:url</tt>: The URL for this entry. Defaults to the polymorphic_url for the record.
 176         # * <tt>:id</tt>: The ID for this entry. Defaults to "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}"
 177         def entry(record, options = {})
 178           @xml.entry do
 179             @xml.id(options[:id] || "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}")
 180
 181             if options[:published] || (record.respond_to?(:created_at) && record.created_at)
 182               @xml.published((options[:published] || record.created_at).xmlschema)
 183             end
 184
 185             if options[:updated] || (record.respond_to?(:updated_at) && record.updated_at)
 186               @xml.updated((options[:updated] || record.updated_at).xmlschema)
 187             end
 188
 189             @xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:url] || @view.polymorphic_url(record))
 190
 191             yield AtomBuilder.new(@xml)
 192           end
 193         end
 194       end
 195
 196     end
 197   end
 198 end