每天一剂Rails良药之resource_feeder

acts_as_taggable/brower_filters/resource_feeder/simply_helpful这四个插件放在legacy包下面，因为它们已经停止更新和维护
我们安装时可以用
[code]
ruby script/plugin install legacy
[/code]
这将同时安装这四个插件
或者使用
[code]
ruby script/plugin install http://dev.rubyonrails.org/svn/rails/plugins/legacy/resource_feeder/
[/code]
今天我们就来看Rails的RSS和ATOM插件resource_feeder
该插件依赖于simply_helpful
这个插件的使用就非常简单了
[code]
class BooksController < ApplicationController

def rss
render_rss_feed_for Book.find(:all, \:order => 'created_at DESC', :limit => 10), {
:feed => {
:title => "Recent Book",
:pub_date => :created_at
}
}
end

end
[/code]
我们来看看核心代码rss.rb:
[code]
require 'resource_feeder/common'

module ResourceFeeder
module Rss
include ResourceFeeder::Common
extend self

def render_rss_feed_for(resources, options = {})
render :text => rss_feed_for(resources, options), :content_type => Mime::RSS
end

def rss_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
use_content_encoded = options[:item].has_key?(:content_encoded)

options[:feed][:title] ||= klass.name.pluralize
options[:feed][:link] ||= SimplyHelpful::PolymorphicRoutes.polymorphic_url(new_record, options[:url_writer])
options[:feed][:language] ||= "en-us"
options[:feed][:ttl] ||= "40"

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| SimplyHelpful::PolymorphicRoutes.polymorphic_url(r, options[:url_writer]) }

rss_root_attributes = { :version => 2.0 }
rss_root_attributes.merge!("xmlns:content" => "http://purl.org/rss/1.0/modules/content/") if use_content_encoded

xml.instruct!

xml.rss(rss_root_attributes) do
xml.channel do
xml.title(options[:feed][:title])
xml.link(options[:feed][:link])
xml.description(options[:feed][:description]) if options[:feed][:description]
xml.language(options[:feed][:language])
xml.ttl(options[:feed][:ttl])

for resource in resources
xml.item do
xml.title(call_or_read(options[:item][:title], resource))
xml.description(call_or_read(options[:item][:description], resource))
if use_content_encoded then
xml.content(:encoded) { xml.cdata!(call_or_read(options[:item][:content_encoded], resource)) }
end
xml.pubDate(call_or_read(options[:item][:pub_date], resource).to_s(:rfc822))
xml.guid(call_or_read(options[:item][:guid] || options[:item][:link] || resource_link, resource))
xml.link(call_or_read(options[:item][:link] || options[:item][:guid] || resource_link, resource))
end
end
end
end
end
end
end
[/code]
其中[b]xml.pubDate(call_or_read(options[:item][:pub_date], resource).to_s(:rfc822))[/b]这行代码运行时说to_s方法报错"wrong number of arguments(1 for 0)"
我把该行代码的to_s方法的参数:rfc822去掉即可成功运行