On recent rails projects, I found myself clinging to a few useful helpers and additions. Here’s a few.
hide_unless
Often in views, I find I want to hide a particular div or element, but only if certain conditions are met. An ajax call might later reveal it, or replace the contents of the div with something.
def hide_unless(condition)
condition ? '' : 'display:none'
end
In use:
<div id="edit_pane" style="<%= hide_unless(@story) %>"></div>
present?
Rails gives us .blank?, but I hate writing things like:
<% if !@stories.blank? %>
... etc
<% end %>
So, I add this as an extension in my projects:
class Object
def present?
!blank?
end
end
And obviously it works on anything: arrays, hashes, nil, etc.
<% if session[:setting].present? %> etc... <% end %>
UPDATE (29-Jun-2008): DHH just committed this to Edge Rails. I have no proof that I had anything to do with it, but I’ll pretend :)
user_owns_it
A common task is to check if the current user owns a particular resource.
def user_owns_it(asset)
asset.respond_to?(:created_by) and asset.created_by and current_user and asset.created_by.id == current_user.id
end
This allows easy checking in views:
<% if user_owns_it(@post) %> link_to "Edit Your Post", edit_post_path(@post) <% end %>
Please share if you have other interesting tidbits from your toolbox!
