Question

我一直在重构我的模型和控制器，以便删除代码重复，到目前为止它似乎都是极好的奶油味。目前我有两个控制器常用的代码，如下所示：

def process_filters
# Filter hash we're going to pass to the model
  filter_to_use = {}

  # To process filters, we first query the model to find out what filters
  # we should be looking for, as the model knows what we can filter.
  Iso.available_filters.each do |filter|
    # We should have our array with our filter listing.
    # Check the purchase order model for a description
    filter_name = filter[0][:filter_name]

    # Filters are stored in a session variable, this way filters survive
    # page reloads, etc.  First thing we do, is set the session if new filters
    # have been set for the filter.
    session_name = session_filter_name( filter_name )
    if params[session_name]
      if params[session_name] == 'All'
        session[session_name] = nil
      else
        session[session_name] = params[session_name]
        filter_to_use[filter_name] = params[session_name]
      end
    elsif session[session_name]
      # If params aren't read, we still need to filter based off the users
      # session
      filter_to_use[filter_name] = session[session_name]
    end
  end

  # Just using this variable for now until I can refactor the helper code
  # so that this is passed in.
  @current_filter_values = filter_to_use

  filter_to_use[:page] = @current_page

  @isos = Iso.find_filtered( filter_to_use )

  if @isos.out_of_bounds?
    filter_to_use[:page] = session[:previous_page] = @current_page = 1
    @isos = Iso.find_filtered( filter_to_use )
  end
end

现在这个代码与另一个控制器中的代码完全相同，除了模型引用（在本例中为Iso）。有没有我可以使该模型参考动态？

基本上我想将Iso引用（包括@iso变量）替换为基于controller.controller_name或类似的东西。

Answer 1

您可以将此代码移动到模块中，将此模块混合到您需要的所有控制器中，并使用模块内部的self.class变量来确定具体的控制器名称。使用此名称，您可以使用标准字符串函数（例如，大写）和Kernel.const_get函数来按类名称获取类。

Answer 2

好的，这就是我最终的结果。我决不是Ruby / Rails的大师，但它对我有用，所以如果他们尝试类似的东西，它可能会指向一个正确方向的人：

module Filtered
  module Controller
    module InstanceMethods
      def process_filters
        # Filter hash we're going to pass to the model
        filter_to_use = {}

        # To process filters, we first query the model to find out what filters
        # we should be looking for, as the model knows what we can filter.
        Kernel.const_get( 
          self.controller_name.singularize.camelize ).available_filters.each do |filter|
          # We should have our array with our filter listing.
          # Check the purchase order model for a description
          filter_name = filter[0][:filter_name]

          # Filters are stored in a session variable, this way filters survive
          # page reloads, etc.  First thing we do, is set the session if new filters
          # have been set for the filter.
          session_name = session_filter_name( filter_name )
          if params[session_name]
            if params[session_name] == 'All'
              session[session_name] = nil
            else
              session[session_name] = params[session_name]
              filter_to_use[filter_name] = params[session_name]
            end
          elsif session[session_name]
            # If params aren't read, we still need to filter based off the users
            # session
            filter_to_use[filter_name] = session[session_name]
          end
        end

        # Just using this variable for now until I can refactor the helper code
        # so that this is passed in.
        self.instance_variable_set( '@current_filter_values', filter_to_use )

        filter_to_use[:page] = self.instance_variable_get( '@current_page' )

        self.instance_variable_set( "@#{self.controller_name}",
          Kernel.const_get( self.controller_name.singularize.camelize ).find_filtered(
            filter_to_use ) )

        if self.instance_variable_get( "@#{self.controller_name}" ).out_of_bounds?
          filter_to_use[:page] = session[:previous_page] = 1
          self.instance_variable_set( "@#{self.controller_name}",
            Kernel.const_get( self.controller_name.singularize.camelize ).find_filtered(
              filter_to_use ) )
        end
      end

      private

      # Quick helper function for generating session variable names
      def session_filter_name( name )
        "#{self.controller_name}_#{name}_filter".to_sym
      end

    end
  end
end

我通过插件，init.rb文件将它包含在我的所有控制器中，如下所示：

# Include hook for controllers
ActionController::Base.class_eval do
  include Filtered::Controller::InstanceMethods
end

如何根据控制器名称查询模型

2 个答案: