atom_feed

atom_feed(options = {}, &block)

Instance Public methods

Adds easy defaults to writing Atom feeds with the Builder template engine (this does not work on ERB or any other template languages).

Full usage example:

config/routes.rb:
  Rails.application.routes.draw do
    resources :posts
    root to: "posts#index"
  end
 
app/controllers/posts_controller.rb:
  class PostsController < ApplicationController::Base
    # GET /posts.html
    # GET /posts.atom
    def index
      @posts = Post.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[0].created_at) if @posts.length > 0
 
    @posts.each do |post|
      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:

:language: Defaults to âen-USâ.
:root_url: The HTML alternative that this feed is doubling for. Defaults to / on the current host.
:url: The URL for this feed. Defaults to the current URL.
:id: The id for this feed. Defaults to âtag:#{request.host},#{options}:#{request.fullpath.split(â.â)}â
:schema_date: The date at which the tag scheme for the feed was first used. A good default is the year you created the feed. See feedvalidator.org/docs/error/InvalidTAG.html for more information. If not specified, 2005 is used (as an âI don't careâ value).
:instruct: 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)
 
    @posts.each do |post|
      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.

Links:

https://github.com/rails/rails/blob/64a2cbf50484033465add3a3f0eb6867e4849400/actionview/lib/action_view/helpers/atom_feed_helper.rb#L96

doc_ruby_on_rails

2025-01-10 15:47:30

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