How to use Squeel to make innested query?

Question

I'd like to build a query builder using squeel, here is how I did:

Parent class:

module ModelFilters
  class Base
    def initialize(user)
      @user = user
    end

    def build(method_name)
      head.where { my { send(method_name) } }
    end

    protected

    def head
    end
  end
end

Child class:

module ModelFilters
  class Collection < Base
    def __showable__
      not_private | author
    end

    protected

    def head
      ::Collection.joins(:collaborators)
    end

    private

    def not_private
      is_private == false
    end

    def author
      user_id == @user.id
    end
  end
end

And finally my call:

a = ModelFilters::Collection.new(user)
a.build(:__showable__)

Actually my problem is that I don't know how Squeel work for innested query, my actual error is undefined local variable or method 'is_private' (obviously).

Is there a way to build something like this using Squeel (or other ActiveRecord query builder)?

Thank you all!

@apneadiving `showable` is the function of the child class (called my the `send` method), while `is_private` is my Model attribute — Rowandish, Jan 16 '15 at 09:37

apneadiving · Accepted Answer · 2015-01-16T10:17:43.430

2

What if you do:

module ModelFilters
  class Base
    def initialize(user)
      @user = user
    end

    def build(method_name)
      head.where { |q| send(method_name, q) }
    end

    protected

    def head
    end
  end
end

module ModelFilters
  class Collection < Base
    def __showable__(q)
      not_private(q) | author(q)
    end

    protected

    def head
      ::Collection.joins(:collaborators)
    end

    private

    def not_private(q)
      q.is_private == false
    end

    def author(q)
      q.user_id == @user.id
    end
  end
end

edited Jan 16 '15 at 10:17

answered Jan 16 '15 at 09:44

apneadiving

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Thank you for your answer, it seems very close to the right solution but actually I get the following error: `PG::UndefinedColumn: ERROR: column collections.my does not exist`. – Rowandish Jan 16 '15 at 10:00
:) never used squeel before, is the my block really necessary? Could you try without it? – apneadiving Jan 16 '15 at 10:01
`my` is used to call instance methods inside the `where` block. I tryed in this way and now everything works: `head.where { |q| send(method_name, q) }`. You can edit your answer and I'll accept it :) – Rowandish Jan 16 '15 at 10:15

How to use Squeel to make innested query?

1 Answers1