Round-trip problem with empty params

[daniel-rikowski]

tl;dr: I've noticed a small problem with empty search queries if the params are piped through url_for (or link_to) and then redirected to Ransack again.

Long example:

1. This url is sent to Rails: /orders?utf8=✓&q[id_eq]=&q[order_code_cont] and subsequentially processed by Ransack via Order.search(params[:q]).
2. Before Order.search is executed the params hash looks like this:

{
  'action' => 'index'
  'controller' => 'orders'
  'q' => {
    'id_eq' => ''
    'order_code_cont' => ''
  }
}

3. After Order.search is executed the params hash looks like this:

{
  'action' => 'index'
  'controller' => 'orders'
  'q' => {
  }
}

Most likely this is because of #201

4. The actual problem shows when I'm using url_for (in this case to add a page param)
   url_for(params.merge(page: 2)) generates this url: /orders?utf8=✓&q=&page=1

5. Suddenly Ransack has to handle an (empty) string instead of a hash which leads to various exceptions.

I can think of two ways to fix this: Either don't change params (e.g. use params.dup before calling delete_if) or use params.presence at the necessary locations. (At Ransack::Adapters::ActiveRecord::Base.ransack and Ransack::Helpers::FormHelper.sort_link)

Thank you in advance!

[jonatack]

Hi @daniel-rikowski, thank you for reporting this issue. The params are being processed in the following method in search.rb which has seen some changes lately. Are you using the latest version of Ransack (version 1.2.3)? Which version of Rails/Ruby? Could you provide a failing test spec for the issue (which would be very helpful), or, even better, a pull request for a solution with tests passing (and failing without it)? Thanks :)

In Ransack::Lib::Ransack::Search:

def initialize(object, params = {}, options = {})
  params = {} unless params.is_a?(Hash)
  (params ||= {}).delete_if { |k, v| [*v].all? { |i| i.blank? && i != false } }
  @context = Context.for(object, options)
  @context.auth_object = options[:auth_object]
  @base = Nodes::Grouping.new(@context, 'and')
  build(params.with_indifferent_access)
end

[daniel-rikowski]

Hello @jonatack

I'm using Ruby 2.0.0p451, Rails 4.1 and Ransack 1.2.3.

I'll try to work on this this week and hopefully make a pull request soon :)

[jonatack]

@daniel-rikowski Super. Which Ransack are you using? The official release, the master branch, or the rails-4.1 branch?

[daniel-rikowski]

I've checked again today and both branches have the same problem. But in my situation it's not only Ransack::Lib::Ransack::Search#initialize but Ransack::Lib::Ransack::Search#ransack too:

def ransack(params = {}, options = {})
  Search.new(self, params ? params.delete_if {
     |k, v| v.blank? && v != false } : params, options)
end

At both places the params parameter is modified by delete_if.

BTW: Why is params cleaned at two separate locations? (Ransack::Adapters::ActiveRecord::Base#ransack and Ransack::Lib::Ransack::Search#initialize) Wouldn't the one at Ransack::Lib::Ransack::Search#initialize be enough? It seems to be more comprehensive, too.

[jonatack]

Fixed with 28433f9.