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Document validations and callbacks Array support for :if and :unless options

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João Britto 2012-03-09 12:12:58 -03:00
parent 8761824037
commit 3288107d30
1 changed files with 16 additions and 2 deletions
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18
railties/guides/source/active_record_validations_callbacks.textile
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@ -531,7 +531,7 @@ Person.new.valid? => ActiveModel::StrictValidationFailed: Name can't be blank
h3. Conditional Validation
Sometimes it will make sense to validate an object just when a given predicate is satisfied. You can do that by using the +:if+ and +:unless+ options, which can take a symbol, a string or a +Proc+. You may use the +:if+ option when you want to specify when the validation *should* happen. If you want to specify when the validation *should not* happen, then you may use the +:unless+ option.
Sometimes it will make sense to validate an object just when a given predicate is satisfied. You can do that by using the +:if+ and +:unless+ options, which can take a symbol, a string, a +Proc+ or an +Array+. You may use the +:if+ option when you want to specify when the validation *should* happen. If you want to specify when the validation *should not* happen, then you may use the +:unless+ option.
h4. Using a Symbol with +:if+ and +:unless+
@ -583,6 +583,20 @@ end
All validations inside of +with_options+ block will have automatically passed the condition +:if => :is_admin?+
h4. Combining validation conditions
On the other hand, when multiple conditions define whether or not a validation should happen, an +Array+ can be used. Moreover, you can apply both +:if:+ and +:unless+ to the same validation.
<ruby>
class Computer < ActiveRecord::Base
validates :mouse, :presence => true,
:if => ["market.retail?", :desktop?]
:unless => Proc.new { |c| c.trackpad.present? }
end
</ruby>
The validation only runs when all the +:if+ conditions and none of the +:unless+ conditions are evaluated to +true+.
h3. Performing Custom Validations
When the built-in validation helpers are not enough for your needs, you can write your own validators or validation methods as you prefer.
@ -1107,7 +1121,7 @@ Post destroyed
h3. Conditional Callbacks
As with validations, we can also make the calling of a callback method conditional on the satisfaction of a given predicate. We can do this using the +:if+ and +:unless+ options, which can take a symbol, a string or a +Proc+. You may use the +:if+ option when you want to specify under which conditions the callback *should* be called. If you want to specify the conditions under which the callback *should not* be called, then you may use the +:unless+ option.
As with validations, we can also make the calling of a callback method conditional on the satisfaction of a given predicate. We can do this using the +:if+ and +:unless+ options, which can take a symbol, a string, a +Proc+ or an +Array+. You may use the +:if+ option when you want to specify under which conditions the callback *should* be called. If you want to specify the conditions under which the callback *should not* be called, then you may use the +:unless+ option.
h4. Using +:if+ and +:unless+ with a +Symbol+