validation help please

[Dave Castellano]

Hi,

Can anyone take a look at this.... i've been banging my head on the
wall for several days trying to figure this out. I can't figure out why
the validation is bypassed. The only clue I have is it seems its not
evaluating :question_type == "standard" to true.

Model:
validates :question_type, :presence => true
if :question_type == "standard"
validates :question, :presence => true
...

Controller:
def create
@question = Question.new(params[:question])
if @question.save
if params[:question_type] == "standard"
flash[:success] = "Question created!"
redirect_to @question
else
.....

new.html.erb:
<%= f.submit 'Save', question_type: "standard" ...

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Posted via http://www.ruby-forum.com/.

[Colin Law]

On 1 March 2013 13:20, Dave Castellano <li...@ruby-forum.com> wrote:
> Hi,
>
> Can anyone take a look at this.... i've been banging my head on the
> wall for several days trying to figure this out. I can't figure out why
> the validation is bypassed. The only clue I have is it seems its not
> evaluating :question_type == "standard" to true.
>
> Model:
> validates :question_type, :presence => true
> if :question_type == "standard"
> validates :question, :presence => true

Is that code just inline in the model? If so then it is only executed
once, when the code is loaded, so the if statement is not tested for
each object being validated. Have a look at the Rails Guide on
ActiveRecord Validations and Callbacks to see ways that you can
accomplish what you want.

Colin

[Walther Diechmann]

Hi Dave,

I believe you should do something along the lines of

Model:

validates_each :question do |record, attr, value|
record.errors.add attr, 'The question is not present!?' if value.blank? and record.question_type=="standard"
end

plz correct me if I'm wrong, Colin :)

cheers,
Walther

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[Colin Law]

On 1 March 2013 13:46, Walther Diechmann <wal...@diechmann.net> wrote:
> Hi Dave,
>
> I believe you should do something along the lines of
>
> Model:
>
> validates_each :question do |record, attr, value|
> record.errors.add attr, 'The question is not present!?' if value.blank? and record.question_type=="standard"
> end
>
> plz correct me if I'm wrong, Colin :)

It might be easier to use :if

Colin

[Frederick Cheung]

On Friday, March 1, 2013 1:20:24 PM UTC, Ruby-Forum.com User wrote:

Hi,

Can anyone take a look at this....  i've been banging my head on the
wall for several days trying to figure this out.  I can't figure out why
the validation is bypassed.  The only clue I have is it seems its not
evaluating :question_type == "standard"  to true.

Model:
validates :question_type,     :presence  => true
    if :question_type == "standard"
      validates :question,        :presence   => true
    ...

This code is evaluated when the model is loaded. It compares the symbol :question_type to the string 'standard' (which are of course never equal) and so doesn't add the validation.

You want the choice of whether to apply the validation or not to be taken when the model is about to be validated. The standard way of doing that is with the :if option

validates :question_type,     :presence  => true 

validates :question,        :presence   => true, :if => :standard_question?

will call the standard_question? method and only enforce the presence validation on question if the method returns true. There is also a lambda form 

validates :question,        :presence   => true, :if => lambda {|record| record.question_type == 'standard'}

Fred

[Dave Castellano]

Ok,

Thank you. I read Rails Guide on ActiveRecord Validations and
Callbacks, specifically Conditional Validation.

So,
validates :question, :presence => true, :if => "question_type.blank?"
placed inline in model should be the simplest way to do this. It does
not work however. My lack of understanding seems to be related to how I
specify question_type in the condition?

As you can see i'm still on the bottom of the steep part of the learning
curve.'

Thanks for the help

[Dave Castellano]

Frederick Cheung wrote in post #1099720:

> On Friday, March 1, 2013 1:20:24 PM UTC, Ruby-Forum.com User wrote:
>> if :question_type == "standard"
>> validates :question, :presence => true
>> ...

> with the :if option
>
> validates :question_type, :presence => true
> validates :question, :presence => true, :if =>
> :standard_question?
>
> will call the standard_question? method and only enforce the presence
> validation on question if the method returns true. There is also a
> lambda
> form
>
> validates :question, :presence => true, :if => lambda {|record|
> record.question_type == 'standard'}
>
> Fred

Thanks Fred,
Got this error
undefined method `standard_question?' for #<Question:0x007f947ddb2e00>
Do I need to write a standard_question method

(I'm beginner)

[Dave Castellano]

Lambda method works, although I don't understand it :-)

Thanks!!

Dave

[Frederick Cheung]

On Friday, March 1, 2013 2:58:53 PM UTC, Ruby-Forum.com User wrote:

> with the :if option
>
> validates :question_type,     :presence  => true
> validates :question,        :presence   => true, :if =>
> :standard_question?
>
> will call the standard_question? method and only enforce the presence
> validation on question if the method returns true. There is also a
> lambda
> form
>
> validates :question,        :presence   => true, :if => lambda {|record|
> record.question_type == 'standard'}
>
> Fred

Thanks Fred,
Got this error
undefined method `standard_question?' for #<Question:0x007f947ddb2e00>
Do I need to write a  standard_question method

Yes - it's up to you to write a standard_question? method. The lambda saves you having to have the condition in a separate method but can make your validation look more cluttered (especially for more complicated conditions).

Fred 

[Dave Castellano]

Thanks again,

Is there a way to add a message if validation fails using lambda method
(I am using Lambda method until I can figure out why

validates :question, :presence => true, :if
=>:standard_question?

generates
undefined method `standard_question?' for #<Question:0x007f947ddb2e00>)

[Jodi Showers]

Dave,  you have to add an instance method "standard_question?" to your model

def standard_question?

end

from the url below you can see that you can pass a :message param to customize the error message

http://guides.rubyonrails.org/active_record_validations_callbacks.html#message

[nannasin smith]

You want the choice of whether to apply the validation or not to be
taken when the model is about to be validated.

http://www.hqew.net