Validates presence of special conditions not working

rubyonrails-talk
1

Here is the validation being used which is not working..

validates_presence_of :name => :controller_name, :if => :redirect?, :message => "must have the same name as the controller."

The model has a string field for name. The model has a boolean field for redirect. The model has a string field for controller_name.

What I want to do is ensure that if the redirect box is checked for true, that the name field matches the controller_name field precisely.

I'm not sure if validates_presence_of will do it. I may have to create a custom validation but am unsure how to proceed.

Much appreciation in advance...

Thanks.

2

validates_presence_of doesn't do that.

Custom validations aren't scary. Adding a class method like

def validates_foo(*attr_names)   options = attr_names.extract_options!   validates_each(attr_names, options) do |record, attr_name, value|     record.errors.add(attr_name, options[:message]) if ...     end   end end

lets you do

validates_foo :attr1, :attr2

You get stuff like :if and :unless for free

Fred

3

Thanks for the explanation Fred.

I tried doing this but it's not working properly:

def self.validates_is_exact(*attr_names)   options = attr_names.extract_options!   validates_each(*(attr_names << options)) do |record, attr_name, value|     if record.send( options[:compare_field] ) == value       record.errors.add(attr_name, options[:message])     end   end   true end

validates_is_exact :name, :compare_field => :controller_name, :if => :redirect?, :message => "must have the same name as the controller."

And ran a test in the console:

e = Page.new e.name = "testname" e.redirect = true e.controller_name = "testname" e.valid?

e.valid?

=> false

Any idea what I might be doing wrong here?

4

I was reading the errors wrong. It's working properly.

Thanks Fred for the advice.

5

Here is the finished validation, corrected:

def self.validates_is_exact(*attr_names)   options = attr_names.extract_options!   validates_each(*(attr_names << options)) do |record, attr_name, value|     if record.send( options[:compare_field] ) != value       record.errors.add(attr_name, options[:message])     end   end   true end

validates_is_exact :name, :compare_field => :controller_name, :if => :redirect?, :message => "must have the same name as the controller."

Basically, it compares the :name field value with the :compare_field field.value and if they are the same, validation is successful. If they are different, it throws my custom message.

Thanks again Fred. It was much easier than I anticipated.