48 lines
1.7 KiB
Markdown
48 lines
1.7 KiB
Markdown
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---
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title: "ActiveRecord: Skipping callbacks like after_save or after_update"
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kind: article
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slug: activerecord-skipping-callbacks-like-after_save-or-after_update
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created_at: 2009-06-07
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tags:
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- General
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---
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Active Records provides callbacks, which is great is you want to perform extra business logic after (or before) saving, creating or destroying an instance of that model.
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However, there are situations where you can easily fall into the trap of creating an infinite loop.
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<pre lang="ruby">class Beer < ActiveRecord::Base
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def after_save
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x = some_magic_method(self)
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update_attribute(:my_attribute, x)
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end
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end</pre>
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The above will give you a nice infinite loop (which doesn't scale). It's possible to update your model, without calling the callbacks and without resorting to SQL.
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<pre lang="ruby">class Beer < ActiveRecord::Base
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def after_save
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x = some_magic_method(self)
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Beer.update_all("my_attribute = #{x}", { :id => self.id })
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end
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end</pre>
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This is a bit unconventional, but it works nicely. You can use all the following ActiveRecord methods to update your model without calling callbacks:
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<ul>
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<li>decrement</li>
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<li>decrement_counter</li>
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<li>delete</li>
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<li>delete_all</li>
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<li>find_by_sql</li>
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<li>increment</li>
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<li>increment_counter</li>
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<li>toggle</li>
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<li>update_all</li>
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<li>update_counters</li>
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</ul>
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<em>An important warning: These methods don't do all the nice SQL injection protection stuff you're used to. In the example, the value of <code>x</code> will be inserted straight into the SQL. I recommend you only use these methods if you're absolutely sure you've cleaned the values you're inserting.</em>
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Check out the rails documentation on how to use these methods.
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