rubyroyd blog

ActiveResource pagination

I didn’t find any good article on how to do pagination on ActiveResource, so here’s my 2ยข. Basically, I wanted to do as less changes to the server as possible. As we already using pagination on the server side, the only change was to add info about total number of items and items per page to the server’s xml response. This is needed by client to properly build pagination links inside it’s view.

Server controller:

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  def index
    @airports = Airport.paginate(:page => params[:page],
                                            :per_page => APP_CONFIG['airports_per_page'])

    respond_to do |format|
      format.html # index.html.erb
      format.xml  { @airports << {
                              :pagination_members_total => @airports.total_entries,
                              :pagination_members_per_page => APP_CONFIG['airports_per_page']
                               }
                    render :xml => @airports
                  }
    end
  end

There’s no pagination done at the client side, we just need to extract the pagination parameters and pass them to will_paginate view helper.

Client controller

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  def index
    current_page = params[:page] || 1
    total_members, per_page = 0
    
    airports = Airport.find(:all, :params => { :page =>  current_page})
    airports.each_index{|x| 
      if airports[x].respond_to?(:pagination_members_total) && airports[x].respond_to?(:pagination_members_per_page)
        total_members = airports[x].pagination_members_total
        per_page = airports[x].pagination_members_per_page
        airports.delete_at x
        break
      end
    }

    @airports = WillPaginate::Collection.create(current_page, per_page, total_members) do |pager|
      pager.replace airports
    end
  end

Client view (same as on server)

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                <%= will_paginate @airports %>

Looks a bit ugly, but works. Please let me know if there’s a better solution.

  1. Igor F says:
    February 15, 2012 at 4:18 PM

    I realized that it can be done with additional server headers.
    Look here https://github.com/Fivell/activeresource-response

  2. CantuMadeleine34 says:
    October 22, 2011 at 8:00 AM

    I had a dream to start my own business, however I did not earn enough amount of money to do this. Thank goodness my colleague advised to take the <a href="http://goodfinance-blog.com/topics/home-loans">home loans</a>. Thus I took the short term loan and realized my old dream.

  3. Sidu says:
    February 14, 2010 at 5:48 PM

    PoxPaginate should take care of this. http://github.com/c42/pox_paginate

  4. Jim says:
    October 12, 2009 at 9:43 PM

    Awesome! I've wrapped this solution into a separate file. require it in your environment.rb file and you should be able to call...

    AnyActiveResource.paginate ... in your client

    and

    AnyActiveRecord.paginate_for_remote ... in your server

    Doesn't really improve on the code just moves the ugliness out of the controllers. :-)

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    class ActiveResource::Base
  def self.paginate(*args)
    total_members, per_page = 0

    options = args.detect{|a| a.is_a?(Hash) && a.has_key?(:params)}
    if options
      params = options[:params]
    else
      return
    end
  
    current_page = params[:page] || 1
    params[:per_page] ||= 30

    rs = find(*args)

    if rs[0].respond_to?(:pagination_members_total) && rs[0].respond_to?(:pagination_members_per_page)
      total_members = rs[0].pagination_members_total
      per_page = rs[0].pagination_members_per_page
      rs.delete_at 0
    end
    
    WillPaginate::Collection.create(current_page, per_page, total_members) do |pager|
      pager.replace rs
    end
  end
end

class ActiveRecord::Base
  def self.paginate_for_remote(*args)
    params = args.detect{|a| a.is_a?(Hash) && a.has_key?(:per_page)}
    
    if params
      per_page = params[:per_page]
    else
      return
    end
    
    rs = paginate(*args)
    rs = [{:pagination_members_total => rs.total_entries,
            :pagination_members_per_page => per_page}] + rs
  end
end

  5. Use a array add to lessen the loop says:
    May 14, 2009 at 9:23 PM

    @airports = [{
    :pagination_members_total => @airports.total_entries,
    :pagination_members_per_page => APP_CONFIG['airports_per_page']
    }] + @airports

    Then
    if airports[0].respond_to?(:pagination_members_total) && airports[0].respond_to?(:pagination_members_per_page)
    total_members = airports[0].pagination_members_total
    per_page = airports[0].pagination_members_per_page
    airports.delete_at 0

    Thanks for the help too....

  6. ettober says:
    March 20, 2009 at 9:41 AM

    Thanks a million for this!

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