the readme of searchlogic

Before I use a library in my application I like to glance at the source and try to at least understand the basics of how it works. If you are like me, a nice little explanation from the author is always helpful:

Searchlogic utilizes method_missing to create all of these named scopes. When it hits method_missing it creates a named scope to ensure it will never hit method missing for that named scope again. Sort of a caching mechanism. It works in the same fashion as ActiveRecord's "find_by_*" methods. This way only the named scopes you need are created and nothing more.

The search object is just a proxy to your model that only delegates calls that map to named scopes and nothing more. This is obviously done for security reasons. It also helps make form integration easier, by type casting values, and playing nice with form_for. This class is pretty simple as well.

That's about it, the named scope options are pretty bare bones and created just like you would manually.

 

Searchlogic利用method_missing的创建这些命名范围的。当它攻击的method_missing它创建一个命名范围，以确保它永远不会达到方法命名范围的method messing。这样的缓存机制。该工程作为的ActiveRecord的“find_by_ *”方法相同的方式。只有这样命名的范围你需要的是创造，仅此而已。

评论

2 楼 orcl_zhang 2010-01-08  

rails中很多地方应用到了method_missing这个方法。
searchlogic是一个不错的应用。

1 楼 orcl_zhang 2009-12-12  

=== Searchlogic provided scopes

Let's take some basic scopes that Searchlogic provides for every model:

  # We have the following relationships

  User.has_many_orders
  Order.has_many :line_items
  LineItem

  # Set conditions on association columns
  User.orders_total_greater_than(20)
  User.orders_line_items_price_greater_than(20)

  # Order by association columns
  User.ascend_by_order_total
  User.descend_by_orders_line_items_price

This is recursive, you can travel through your associations simply by typing it in the name of the method. Again these are just named scopes. You can chain them together, call methods off of them, etc.
==========

Accident.belongs_to :employee
Employee.has_many :accidents

Employee.find_by_name['z']
Accident.employee_name_like['z']

So magic!