Generating RSS in Rails 2 is pretty easy.
In the simplest case, all that is required is an extra view file to create the RSS output.
Consider a simple (RESTful) blog example:
route.rb:
...
map.home '', :controller => 'posts', :action => 'index'
map.resources :posts
...
posts_controller.rb:
def index
@posts = Post.find(:all)
end
When I generated the posts controller, Rails created an ‘index.html.erb’ file for the index action. It’s an ugly file name, but it helps Rails figure out what to do: ‘index’ is the action, ‘html’ and ‘erb’ are the format and builder to use. To generate RSS we want to use the XML Builder, so the file name to use is ‘index.rss.builder’. And the file contents should look something like this:
xml.instruct! :xml, :version => "1.0"
xml.rss :version => "2.0" do
xml.channel do
xml.title "My Blog"
xml.description "My Fantastic Blog"
xml.link posts_url
for post in @posts
xml.item do
xml.title post.title
xml.description post.content
xml.pubDate post.created_at.to_s(:rfc822)
xml.link post_url(post)
end
end
end
end
Now that is really easy, but I’ve experienced two issues with this.
The first issue is with layouts. If the controller uses a layout for all actions (using layout => "mylayout") it will cause Rails to look for a layout file named ‘layouts/posts.rss.erb’. This can be bypassed by excluding the layout for the rss format, like so:
def index
@posts = Post.find(:all)
respond_to do |format|
format.html
format.rss { render :layout => false }
end
end
The other issue I experienced was with the will_paginate plug-in where my index method looks like this:
def index
@posts = Post.paginate(:per_page => 10, :page => params[:page])
end
The problem is that only 10 posts will show up in the RSS feed, which is not what I want.
There are at least two good ways I came up with to deal with this issue. The my preferred way is create a new feed method that is excluded from the layout and returns all posts.
def feed
@posts = Post.find(:all)
end
with a new route:
map.connect 'posts/feed.:format', :controller => 'posts', :action => 'feed'
The second way examines the request format and grabs the posts via paginate for HTML and find for RSS
def index
if request.format.html?
@posts = Post.paginate(:per_page => 10, :page => params[:page])
else
@posts = Post.find(:all)
end
respond_to do |format|
format.html
format.rss { render :layout => fals }
end
end
I like the first way better. Seems a little cleaner. I like small methods.
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