JasonDaly.name

Reverse Pagination Count with Kaminari

When displaying a threaded conversation with messages paginated by Kaminari, I had the unique requirement to display messages in DESC order by their creation date. This meant that if there were 12 messages with 5 per page, the breakdown would be

• Page 1: messages 12 - 8
• Page 2: messages 7 - 3
• Page 3: messages 2 - 1

To actually display the message number next to each message, it had to be calculated using the methods added to a paginated model by Kaminari (see the :message_number value below)

<div class="comments">
  <% @messages.each_with_index do |message, index| %>
    <%= render :partial => 'message', :locals => {:message => message, :message_number => @messages.total_count - (@messages.current_page - 1) * @messages.limit_value - index} %>
  <% end %>
</div>

For now this is the only place the above calculation is relevant. Should I need it in multiple places I would move the above calculation to a helper.

Parsing and Pluralizing Model Names in Rails

Recently working with Kaminari, I wanted to have text display next to the pagination links like

283 Items - Page 3/15

I wanted the Items text to be dynamic according to the model the paginated collection was representing. Looking over my model names I found converting each to a human readable version would work great in all cases I needed a paginator. Simply using pluralize (I use singular form for my models) will not work in all cases.

• User would become Users - great!
• Page would become Pages - great!
• ConversationMessage would become ConversationMessages - yuck!

For the ConversationMessage model, I really only wanted to display the items in the collection to the user as Messages, not ConversationMessages or even Conversation Messages. I found this was common for my other models on the many side of a one-to-many relationship too (ie. for my UserComplaint model, I wanted the pagination text to say simply Complaints).

The following works beautifully for all models I currently have in place

@collection.first.class.name.underscore.humanize.pluralize.titleize[/\s?([^\s]+)$/, 1]

With models having their default names (in the plural form), the .pluralize call can be removed.