lib/resource_feeder/atom.rb
require "builder"
module ResourceFeeder
module Atom
extend self
def render_atom_feed_for(resources, options = {})
render :text => atom_feed_for(resources, options), :content_type => Mime::ATOM
end
def atom_feed_for(resources, options = {})
xml = Builder::XmlMarkup.new(:indent => 2)
options[:feed] ||= {}
options[:item] ||= {}
options[:url_writer] ||= self
if options[:class] || resources.first
klass = options[:class] || resources.first.class
new_record = klass.new
else
options[:feed] = { :title => "Empty", :link => "http://example.com" }
end
options[:feed][:title] ||= klass.name.pluralize
options[:feed][:id] ||= "tag:#{request.host_with_port}:#{klass.name.pluralize}"
options[:feed][:link] ||= polymorphic_url(new_record)
options[:item][:title] ||= [ :title, :subject, :headline, :name ]
options[:item][:description] ||= [ :description, :body, :content ]
options[:item][:pub_date] ||= [ :updated_at, :updated_on, :created_at, :created_on ]
resource_link = lambda { |r| polymorphic_url(new_record) }
xml.instruct!
xml.feed "xml:lang" => "en-US", "xmlns" => 'http://www.w3.org/2005/Atom' do
xml.title(options[:feed][:title])
xml.id(options[:feed][:id])
xml.link(:rel => 'alternate', :type => 'text/html', :href => options[:feed][:link])
xml.link(:rel => 'self', :type => 'application/atom+xml', :href => options[:feed][:self]) if options[:feed][:self]
xml.subtitle(options[:feed][:description]) if options[:feed][:description]
for resource in resources
published_at = call_or_read(options[:item][:pub_date], resource)
xml.entry do
xml.title(call_or_read(options[:item][:title], resource))
xml.content(call_or_read(options[:item][:description], resource), :type => 'html')
xml.id("tag:#{request.host_with_port},#{published_at.xmlschema}:#{call_or_read(options[:item][:guid] || options[:item][:link] || resource_link, resource)}")
xml.published(published_at.xmlschema)
xml.updated((resource.respond_to?(:updated_at) ? call_or_read(options[:item][:pub_date] || :updated_at, resource) : published_at).xmlschema)
xml.link(:rel => 'alternate', :type => 'text/html', :href => call_or_read(options[:item][:link] || options[:item][:guid] || resource_link, resource))
end
end
end
end
private
def call_or_read(procedure_or_attributes, resource)
case procedure_or_attributes
when Array
attributes = procedure_or_attributes
resource.send(attributes.select { |a| resource.respond_to?(a) }.first)
when Symbol
attribute = procedure_or_attributes
resource.send(attribute)
when Proc
procedure = procedure_or_attributes
procedure.call(resource)
end
end
end
end