Question

I have made a custom link renderer for will_paginate and have placed the code in lib/my_link_renderer.rb

require 'will_paginate/view_helpers/link_renderer'
require 'will_paginate/view_helpers/action_view'

class MyLinkRenderer < WillPaginate::ActionView::LinkRenderer
  include ListsHelper
  def to_html
    html = pagination.map do |item|
      item.is_a?(Fixnum) ?
        page_number(item) :
        send(item)
    end.join(@options[:link_separator])
    html << @options[:extra_html] if @options[:extra_html]

    @options[:container] ? html_container(html) : html
  end
end

Then I use it like so:

  <%= will_paginate @stuff, 
        :previous_label=>'<input class="btn" type="button" value="Previous"/>',
        :next_label=>'<input class="btn" type="button" value="Next" />',
        :extra_html=>a_helper,
        :renderer => 'WillPaginate::ActionView::MyLinkRenderer'
  %>

It works the first time but the second time I get a uninitialized constant WillPaginate::ActionView::MyLinkRenderer error. I believe I am loading files from lib into my application correctly in my config/application.rb:

# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
config.autoload_paths += %W(#{config.root}/lib)
config.autoload_paths += Dir["#{config.root}/lib/**/"]

I get the same problem in the console.

system :001 > WillPaginate::ActionView::MyLinkRenderer
 => MyLinkRenderer 
system :002 > WillPaginate::ActionView::MyLinkRenderer
NameError: uninitialized constant WillPaginate::ActionView::MyLinkRenderer

Suspect this has something to do with how rails autoloads things. Should I not be using autoload? Should I be explictly requiring ‘./lib/my_link_renderer’?

I should note this only happens on my production server.

Answer 1

Your MyLinkRenderer class isn’t in the WillPaginate::ActionView module, so referring to it as WillPaginate::ActionView::MyLinkRenderer should never work.

You should either refer to it as MyLinkRenderer (without the module name) or define it to be in that module, and move it to lib/will_paginate/action_view/my_link_renderer.rb:

module WillPaginate::ActionView
  class MyLinkRenderer < LinkRenderer
    …
  end
end

The fact that it works first time is a quirk of the way Rails uses const_missing to implement autoloading. If you’re curious, see this answer: https://stackoverflow.com/a/10633531/5168