Daily Refactor #58: Move Method to Query Model

The Refactoring

Using move method I was able to move a chunk of duplicated code from the QueriesController into the Query model.

Before

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# app/controllers/queries_controller.rb
  def new
    # ...
    params[:fields].each do |field|
      @query.add_filter(field, params[:operators][field], params[:values][field])
    end if params[:fields]
    @query.group_by ||= params[:group_by]
    # ...
  end
 
  def edit
      # ...
      params[:fields].each do |field|
        @query.add_filter(field, params[:operators][field], params[:values][field])
      end if params[:fields]
      @query.attributes = params[:query]
      # ...
  end
 
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# app/models/query.rb
class Query < ActiveRecord::Base
  # ...
end

After

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# app/controllers/queries_controller.rb
class QueriesController < ApplicationController
  def new
    # ...
    @query.add_filters(params[:fields], params[:operators], params[:values]) if params[:fields]
    @query.group_by ||= params[:group_by]
    # ...
  end
 
  def edit
      # ...
      @query.add_filters(params[:fields], params[:operators], params[:values]) if params[:fields]
      @query.attributes = params[:query]
      # ...
  end
end
 
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class Query < ActiveRecord::Base
  # Add multiple filters using +add_filter+
  def add_filters(fields, operators, values)
    fields.each do |field|
      add_filter(field, operators[field], values[field])
    end
  end
end

Review

Even though this refactoring is simple, it’s useful for three reasons:

  1. It reduces the complexity of the Controller
  2. It removes some duplication in the Controller
  3. It makes a new method available on the Model that can be reused in other places

Reference commit