Ruby on Rails/ActionView/ERb
ERb (Embedded Ruby) is the default template language included with Rails. It is very similar to PHP, JSP and ASP.
Tags for Embedding Ruby
- <%= %> will render the result returned from the embedded Ruby expression as text
- <% %> will execute the embedded expression without rendering the result
- <% -%> will execute the embedded expression without rendering the result and will suppress trailing whitespace
- <%- %> will execute the embedded expression without rendering the result and will suppress leading whitespace
- <%# %> will cause the embedded expression to be parsed as a comment
ERb Utility Methods
There are a couple utility methods which are part of ERb that you may encounter when developing Rails applications:
- h(s) or html_escape(s) - A utility method for escaping HTML tag characters in the supplied String s
- u(s) or url_encode(s) - A utility method for encoding the String s as a URL
<h1>People</h1> <ul> <% @people.each do |person| -%> <li><%= person.first_name %></li> <% end -%> </ul>
If @people contained an array of Person instances, this would render something like the following:
<h1>People</h1> <ul> <li>Bob</li> <li>Joe</li> <li>Mary</li> </ul>
- While it is possible to put business logic in the view this should be avoided. Business logic belongs in the model where it can be easily tested and reused.
- The line
<%= render :partial => '/layouts/menu' %>will render a the partial app/views/layouts/_menu.