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require 'set'
# Adds easy defaults to writing Atom feeds with the Builder template engine (this does not work on ERb or any other
# template languages).
module ActionView
module Helpers #:nodoc:
module AtomFeedHelper
# Full usage example:
#
# config/routes.rb:
# ActionController::Routing::Routes.draw do |map|
# map.resources :posts
# map.root :controller => "posts"
# end
#
# app/controllers/posts_controller.rb:
# class PostsController < ApplicationController::Base
# # GET /posts.html
# # GET /posts.atom
# def index
# @posts = Post.find(:all)
#
# respond_to do |format|
# format.html
# format.atom
# end
# end
# end
#
# app/views/posts/index.atom.builder:
# atom_feed do |feed|
# feed.title("My great blog!")
# feed.updated(@posts.first.created_at)
#
# for post in @posts
# feed.entry(post) do |entry|
# entry.title(post.title)
# entry.content(post.body, :type => 'html')
#
# entry.author do |author|
# author.name("DHH")
# end
# end
# end
# end
#
# The options for atom_feed are:
#
# * <tt>:language</tt>: Defaults to "en-US".
# * <tt>:root_url</tt>: The HTML alternative that this feed is doubling for. Defaults to / on the current host.
# * <tt>:url</tt>: The URL for this feed. Defaults to the current URL.
# * <tt>:id</tt>: The id for this feed. Defaults to "tag:#{request.host},#{options[:schema_date]}:#{request.request_uri.split(".")[0]}"
# * <tt>:schema_date</tt>: The date at which the tag scheme for the feed was first used. A good default is the year you
# created the feed. See http://feedvalidator.org/docs/error/InvalidTAG.html for more information. If not specified,
# 2005 is used (as an "I don't care" value).
# * <tt>:instruct</tt>: Hash of XML processing instructions in the form {target => {attribute => value, }} or {target => [{attribute => value, }, ]}
#
# Other namespaces can be added to the root element:
#
# app/views/posts/index.atom.builder:
# atom_feed({'xmlns:app' => 'http://www.w3.org/2007/app',
# 'xmlns:openSearch' => 'http://a9.com/-/spec/opensearch/1.1/'}) do |feed|
# feed.title("My great blog!")
# feed.updated((@posts.first.created_at))
# feed.tag!(openSearch:totalResults, 10)
#
# for post in @posts
# feed.entry(post) do |entry|
# entry.title(post.title)
# entry.content(post.body, :type => 'html')
# entry.tag!('app:edited', Time.now)
#
# entry.author do |author|
# author.name("DHH")
# end
# end
# end
# end
#
# The Atom spec defines five elements (content rights title subtitle
# summary) which may directly contain xhtml content if :type => 'xhtml'
# is specified as an attribute. If so, this helper will take care of
# the enclosing div and xhtml namespace declaration. Example usage:
#
# entry.summary :type => 'xhtml' do |xhtml|
# xhtml.p pluralize(order.line_items.count, "line item")
# xhtml.p "Shipped to #{order.address}"
# xhtml.p "Paid by #{order.pay_type}"
# end
#
#
# atom_feed yields an AtomFeedBuilder instance. Nested elements yield
# an AtomBuilder instance.
def atom_feed(options = {}, &block)
if options[:schema_date]
options[:schema_date] = options[:schema_date].strftime("%Y-%m-%d") if options[:schema_date].respond_to?(:strftime)
else
options[:schema_date] = "2005" # The Atom spec copyright date
end
xml = options.delete(:xml) || eval("xml", block.binding)
xml.instruct!
if options[:instruct]
options[:instruct].each do |target,attrs|
if attrs.respond_to?(:keys)
xml.instruct!(target, attrs)
elsif attrs.respond_to?(:each)
attrs.each { |attr_group| xml.instruct!(target, attr_group) }
end
end
end
feed_opts = {"xml:lang" => options[:language] || "en-US", "xmlns" => 'http://www.w3.org/2005/Atom'}
feed_opts.merge!(options).reject!{|k,v| !k.to_s.match(/^xml/)}
xml.feed(feed_opts) do
xml.id(options[:id] || "tag:#{request.host},#{options[:schema_date]}:#{request.request_uri.split(".")[0]}")
xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:root_url] || (request.protocol + request.host_with_port))
xml.link(:rel => 'self', :type => 'application/atom+xml', :href => options[:url] || request.url)
yield AtomFeedBuilder.new(xml, self, options)
end
end
class AtomBuilder
XHTML_TAG_NAMES = %w(content rights title subtitle summary).to_set
def initialize(xml)
@xml = xml
end
private
# Delegate to xml builder, first wrapping the element in a xhtml
# namespaced div element if the method and arguments indicate
# that an xhtml_block? is desired.
def method_missing(method, *arguments, &block)
if xhtml_block?(method, arguments)
@xml.__send__(method, *arguments) do
@xml.div(:xmlns => 'http://www.w3.org/1999/xhtml') do |xhtml|
block.call(xhtml)
end
end
else
@xml.__send__(method, *arguments, &block)
end
end
# True if the method name matches one of the five elements defined
# in the Atom spec as potentially containing XHTML content and
# if :type => 'xhtml' is, in fact, specified.
def xhtml_block?(method, arguments)
if XHTML_TAG_NAMES.include?(method.to_s)
last = arguments.last
last.is_a?(Hash) && last[:type].to_s == 'xhtml'
end
end
end
class AtomFeedBuilder < AtomBuilder
def initialize(xml, view, feed_options = {})
@xml, @view, @feed_options = xml, view, feed_options
end
# Accepts a Date or Time object and inserts it in the proper format. If nil is passed, current time in UTC is used.
def updated(date_or_time = nil)
@xml.updated((date_or_time || Time.now.utc).xmlschema)
end
# Creates an entry tag for a specific record and prefills the id using class and id.
#
# Options:
#
# * <tt>:published</tt>: Time first published. Defaults to the created_at attribute on the record if one such exists.
# * <tt>:updated</tt>: Time of update. Defaults to the updated_at attribute on the record if one such exists.
# * <tt>:url</tt>: The URL for this entry. Defaults to the polymorphic_url for the record.
# * <tt>:id</tt>: The ID for this entry. Defaults to "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}"
def entry(record, options = {})
@xml.entry do
@xml.id(options[:id] || "tag:#{@view.request.host},#{@feed_options[:schema_date]}:#{record.class}/#{record.id}")
if options[:published] || (record.respond_to?(:created_at) && record.created_at)
@xml.published((options[:published] || record.created_at).xmlschema)
end
if options[:updated] || (record.respond_to?(:updated_at) && record.updated_at)
@xml.updated((options[:updated] || record.updated_at).xmlschema)
end
@xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:url] || @view.polymorphic_url(record))
yield AtomBuilder.new(@xml)
end
end
end
end
end
end
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