Question

Let me get started by saying I am a Rails newbie so I’m going to try and explain this the best that I can. As a reference, please see this thread which describes exactly what is happening to me, except the fix doesn’t seem to be working.

Problems with limit method in Rails 3.2 and hash ordering

I have a database with events that I am trying to sort by the primary key “id”. I tried following the Railscast on sortable table columns here:

http://railscasts.com/episodes/228-sortable-table-columns

The sorting works properly but the sort happens on the entire column instead of just the “last 50”.

Controller Code:

def index
  @events = Event.order(sort_column + " " + sort_direction).page(params[:page]).last(50)
  @events = @events.sort_by(&:id)
  @events = Kaminari.paginate_array(@events).page(params[:page]).per(10)
end

def sort_column
  Event.column_names.include?(params[:sort]) ? params[:sort] : "event_id"
end

def sort_direction
  %w[asc desc].include?(params[:direction]) ? params[:direction] : "desc"
end

Application_helper:

    def sortable(column, title = nil)
  title ||= column.titleize
  direction = column == sort_column && sort_direction == "desc" ? "asc" : "desc"
  link_to title, :sort => sort_column, :direction => direction
end

Finally, in the index view, I call it like this:

<th><%= sortable  "event_id" %></th>

I’m sorry if this question has already been answered, any help on this subject would be greatly appreciated.

EDIT

Thanks for the quick reply. I understand what you did there, but now I get an exception for some reason in my index view.

 undefined method `id' for #<Array:0x00000004170c10>

Extracted source (around line #25):

22:   <tbody>
23:     <% @events.each do |event| %>
24:       <tr>
25:         <td><%= link_to event.id, event_path(event) %></td>
26:         <td><%= event.event_date_time_local %></td>
27:         <td><%= EventType.find(id =    event.event_type_id).event_type %></td>
28:         <td>

Answer 1

You said “instead of the last 50” but that is all you are returning. The last 50 found items after sorting based on sort_column and direction.

@events = Event.order(sort_column + " " + sort_direction).page(params[:page]).last(50)
#Sorted the last 50 by sort_column and direction

@events = @events.sort_by(&:id)
#sorted again by id and lost the first sort

To get all events and then sort the last fifty you can do

@events = Event.order(sort_column + " " + sort_direction).page(params[:page])
last_fifty = @events.pop(50) # remove last 50 and return it

@events << last_fifty.sort_by(&:id) # insert last fifty back sorted by id

Edit:

Sorry, instead of

@events << last_fifty.sort_by(&:id)

try

@events.concat last_fifty.sort_by(&:id)