Notes posted by concept47

expires_in option

You can actually pass in an expires_in option that sets how long Rails should show the fragment before deleting it so as an example …

<% cache('homepage_sidebar', :expires_in => 10.minutes) do %>
  <div>
    ...
  </div>
<% end %>

This only used to work with memcached but it now works with other types of Rails stores, MemoryStore, FileStore (had to use a plugin to get this behavior before) etc etc

So in your controller. You’d just do …

@posts = Posts.all if fragment_exists?('homepage_sidebar') 

to avoid performing a pointless SQL query.

use validates :name, :presence => true instead

validates_presence_of is a holdover from the Rails 2 days.

This is the way it is done now http://guides.rubyonrails.org/active_record_validations_callbacks.html#presence

be aware that this writes to tmp/cache

Its supposed to be http caching, but Rails will actually cache the response to whatever you specified as the cache store, *as well*, but only if you specify :public => true. The default is filestore so it will try to write to tmp/cache.

Only a problem if you don’t have the proper permissions set, in that scenario your apache/nginx logs could fill up very quickly with “permission denied errors”

Full explanation is here http://blog.tonycode.com/archives/418

link to nothing if link_to_if condition is false

When the link_to_if condition is false you can get this helper to display nothing by doing something like this

<%= link_to_if(message.user, 'Poster', message.user){} %>

^ That will display nothing if message.user does not exist.