方法调用缓存导致的SearchLogic问题

Question

我正在尝试使用搜索逻辑gem在几个表Post has_many assets上执行搜索。我需要它来执行左外部连接，而不是在不存在的资产事件中执行内部连接。

根据下面的内容，查询是使用所需的外部连接生成的，并且通过了前三个测试，但在最后一个测试中失败了。但是，如果我只运行最后一个测试，它就会通过。

失败的原因是@search_logic_filter变量仅在第一个测试中设置，并用于其余所有测试。

以这种方式设置@search_logic_filter的原因是，它是对method_missing的唯一调用，该调用携带传递给Post.title_or_body_or...like("fun")的动态搜索逻辑方法调用的参数

有没有更好的方法来设置过滤器参数？

test "find posts and assets by filter for user" do
  customer = users(:customer)

  create_post_for_user(customer, {:body => "Rails is fun", :tags => "rails ruby"})
  create_post_for_user(customer, {:body => "Fun is what Emacs is all about", :title => "emacs"})


  # File with post
  asset_post = create_post_for_user(customer, {:body => "Ruby is pretty fun too",
                                     :tags => "ruby"})
  asset_post.assets << Asset.new(:upload_file_name => "ruby_tips",
                                :upload_file_size => 100,
                                :upload_content_type => "text")
  asset_post.save

  # search post
  assert_equal 3, Post.find_for_user(customer.id, "fun").size
  assert_equal 2, Post.find_for_user(customer.id, "ruby").size
  assert_equal 1, Post.find_for_user(customer.id, "emacs").size

  # search asset
  puts "about to run last test"
  assert_equal 1, Post.find_for_user(customer.id, "ruby_tips").size
end

class Post < ActiveRecord::Base

  def self.find_for_user(user_id, filter, page=1)
    Post.
      user_id_equals(user_id).
      title_or_body_or_tags_or_assets_upload_file_name_like(filter).all
  end

  class << self
    def method_missing(name, *args, &block)
      if name.to_s =~ /\w+_or_\w+_like$/
        # ** only gets here once **
        @search_logic_filter = args.first
        super
      elsif name == :assets_upload_file_name_like
        # args is [] here which is the reason for the above setting of @search_logic_filter
        named_scope :assets_upload_file_name_like, lambda {
          {:joins => "left outer join assets on posts.id = assets.post_id",
            :conditions => "assets.upload_file_name like '%#{@search_logic_filter}%'"}
        }
        assets_upload_file_name_like
      else
        super
      end
    end
  end
end

** update这是为最终测试运行的查询。请注意，upload_file_name参数是“有趣的”，而不是“ruby”。对于upload_file_name列的所有测试，都存在'fun‘参数，但它只对最后一个测试有影响。

SELECT `posts`.* 
FROM `posts` 
  left outer join assets 
    on posts.id = assets.post_id 
WHERE (
  ((posts.title LIKE '%ruby_tips%') OR (posts.body LIKE '%ruby_tips%') OR (posts.tags LIKE '%ruby_tips%') OR (assets.upload_file_name like '%fun%')) 
  AND (posts.user_id = 20549131)
)

Answer 1

您不应该以这种方式声明named_scope assets_upload_file_name_like。当它第一次被调用时，名为assets_upload_file_name_like的作用域被定义为根据当时@search_logic_filter的值生成的:conditions的值。您应该改为在lambda上设置该参数。

也不需要使用method_missing。只需在Post类中声明named_scope即可。另外，应该对查询进行过滤，以防止SQL注入攻击。

class Post < ActiveRecord::Base
  named_scope :assets_upload_file_name_like, lambda { |file_name| {
    :joins => "left outer join assets on posts.id = assets.post_id",
    # Prevent SQL injection.
    :conditions => ["assets.upload_file_name like ?", "%#{file_name}%"]
  }}
end