RailsTips.org

There are a few view related things of late I’ve been using to make my code a bit more readable. Trust me, they are nothing new, but for whatever reason I hadn’t jumped on the train.

div_for

This doesn’t do anything special but saves some typing and I tend to think it makes things a bit more aesthetically pleasing in TextMate. Using div_for, the following:

<div id="<%= dom_id attachment %>" class="<%= dom_class attachment %>">
    ... removed for clarity ...
</div>

becomes..

<%- div_for attachment do -%>
    ... removed for clarity ...
<%- end %>

You can also use it’s companion, content_tag_for in the case where you are creating table rows or something:

<%- content_tag_for :tr attachment do -%>
    <td>... removed for clarity ...</td>
<%- end %>

local_assigns

Want to pass in optional parameters to a partial rendering? local_assigns is the key to your problems.

<%- if local_assigns.has_key?(:show_project) -%>
    <h3><%= time_entry.project.name %></h3>
<%- end -%>

If you did <%= render :partial => 'foo', :locals => {:time_entry => time_entry, :show_project => true} %>, the project heading would be shown but if you just did <%= render :partial => 'foo', :locals => {:time_entry => time_entry} %> without the :show_project hash key, the heading would not be printed. That might be a bad example, but you get the idea.

content_tag

Obie mentioned a good use for this in the Rails Way, which is in combo with an if statement for some one line goodness. Take the following for example:

<%- if current_user.authorized_to_edit?(user) -%>
    <span class="actions">
        <%= link_to 'Edit', edit_user_path(user) %>
    </span>
<%- end -%>

That works ok, but using content_tag you can easily put it on one line like so:

<%= content_tag 'span', link_to('Edit', edit_user_path(user), :class => 'actions') if current_user.authorized_to_edit?(user) %>    

The two examples put out the same html with the same permissions but the latter is much more succinct.

debug

In PHP, it was var_dump. In ColdFusion is was <cfdump>. Somehow, I overlooked debug in rails for almost a year. Simply call <%= debug @projects %> in your view and you will get a to_yaml representation of the variable wrapped in pre tags.

I’m sure there are tons of others that I’m not super aware of, but these are a few that I’ve found helpful of late. Anybody have other favorites? Maybe concat mixed with a block? Maybe some capture action?