Views in Rails

Lecture Notes for CS349W
Fall Quarter 2008
John Ousterhout

• .rhtml file: template with embedded Ruby code.
• View defaults to file with same name as action method.
• Can also specify view explicitly.
• View executes in the same variable scope as the controller:
  • Template accesses "global" variables.
  • May cause conflict issues if page has many independent sections.
• Rails facilities for use in templates:
  • h function for escaping HTML special characters
  • "Helper methods":
    • Formatting:

      distance_of_time_in_words
      excerpt
      pluralize
      

    • Generating links:

      link_to "Delete", { :action => "delete", :id => @product},
                        { :confirm => "Are you sure?" }
      

    • Forms:

      <% form_for :student :url => {:action => :create} do |form| %>
        <p>Last name: <%= form.text_field :last :size => 30 %></p>
        <p>First name: <%= form.text_field :first :size => 30 %></p>
        ...
      <% end %>
      

      Form helpers automate some of the error handling if a form is submitted with invalid data (more on this later under Fiz).
  • Layouts:
    • Define a standard HTML frame displaying page header, navigation tabs, sidebars, etc.
    • Layout gets used for all views in a controller.
    • Layout indicates where the body of the page should be rendered; at this point the particular view is expanded and substituted.
  • Partial templates: encapsulate reusable components (e.g., shopping cart).
    • A view can incorporate any number of partial templates.
    • Partial templates can incorporate other partial templates.