Rails - Jan 2006 - How to display the error messages from the controller

I have a wizard which consists of two pages. To keep it simple let''s
say
that the first page asks the user to select a state from the drop down menu.
In case the user doesn''t select any state, an error message needs to be
displayed.

Ideally I would like to do something like this.

  def new
    selected_value = params[:addevent][:state_id]
    if selected_value == "-1"
      errors.add(:state_id,"Please select a valid state")
    else
      # go to the next page
    end
  end


But errors is not available in the controller. It''s available only in
the
model. I could use flash[:notice] but using errors would have have helped.
It would have kept everything consistent with the other error message.

Anything I''m missing here.

Thanks.
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On Jan 11, 2006, at 9:56 AM, Neeraj Kumar wrote:
> I have a wizard which consists of two pages. To keep it simple  
> let''s say that the first page asks the user to select a state from
> the drop down menu. In case the user doesn''t select any state, an
> error message needs to be displayed.
>
> Ideally I would like to do something like this.
>
>   def new
>     selected_value = params[:addevent][:state_id]
>     if selected_value == "-1"
>       errors.add(:state_id,"Please select a valid state")
>     else
>       # go to the next page
>     end
>   end
>
>
> But errors is not available in the controller. It''s available only
> in the model. I could use flash[:notice] but using errors would  
> have have helped. It would have kept everything consistent with the  
> other error message.
>
I''m not sure I understand why your controller has to add the error  
message.  Does state_id belong to a model, or is it kind of  
"floating" as unrelated data?

If it belongs to a model, I would do the check inside your model by  
overriding the "validate" method.

e.g.

class User < ActiveRecord::Base
   def validate
     if state_id == -1
       errors.add :state_id, "isn''t valid"
     end
   end
end

If it''s floating data, you can either attach it to a model:

class User < ActiveRecord::Base
   attr_accessor :state_id #not in the database, but connected with  
the User model
end

or you can handle it separately by using the flash, as you suggested.

Duane Johnson
(canadaduane)
http://blog.inquirylabs.com/

Thanks Duane.

As I mentioned it''s a wizard. The state_id is related to the database
but it
will be saved only when the rest of the data comes from the page2.

One the page1, the user has to choose a state that''s it and hit enter.
I
need to verify if a state has been selected or not. I could use flash here
but then it''s difficult to get the same look-n-feel. For example:
1) Displaying messages like (one error prevented the submission of form).
2) A state must be selected.

Having the same look-n-feel is difficult with flash and hence I was looking
for an easier way.

-=- Neeraj

On 1/11/06, Duane Johnson <duane.johnson@gmail.com>
wrote:
>
>
> On Jan 11, 2006, at 9:56 AM, Neeraj Kumar wrote:
>
> > I have a wizard which consists of two pages. To keep it simple
> > let''s say that the first page asks the user to select a state
from
> > the drop down menu. In case the user doesn''t select any
state, an
> > error message needs to be displayed.
> >
> > Ideally I would like to do something like this.
> >
> >   def new
> >     selected_value = params[:addevent][:state_id]
> >     if selected_value == "-1"
> >       errors.add(:state_id,"Please select a valid state")
> >     else
> >       # go to the next page
> >     end
> >   end
> >
> >
> > But errors is not available in the controller. It''s available
only
> > in the model. I could use flash[:notice] but using errors would
> > have have helped. It would have kept everything consistent with the
> > other error message.
> >
>
> I''m not sure I understand why your controller has to add the error
> message.  Does state_id belong to a model, or is it kind of
> "floating" as unrelated data?
>
> If it belongs to a model, I would do the check inside your model by
> overriding the "validate" method.
>
> e.g.
>
> class User < ActiveRecord::Base
>    def validate
>      if state_id == -1
>        errors.add :state_id, "isn''t valid"
>      end
>    end
> end
>
> If it''s floating data, you can either attach it to a model:
>
> class User < ActiveRecord::Base
>    attr_accessor :state_id #not in the database, but connected with
> the User model
> end
>
> or you can handle it separately by using the flash, as you suggested.
>
> Duane Johnson
> (canadaduane)
> http://blog.inquirylabs.com/
>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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On 1/11/06, Duane Johnson <duane.johnson@gmail.com>
wrote:
>
> On Jan 11, 2006, at 9:56 AM, Neeraj Kumar wrote:
>
> > I have a wizard which consists of two pages. To keep it simple
> > let''s say that the first page asks the user to select a state
from
> > the drop down menu. In case the user doesn''t select any
state, an
> > error message needs to be displayed.
> >
> > Ideally I would like to do something like this.
> >
> >   def new
> >     selected_value = params[:addevent][:state_id]
> >     if selected_value == "-1"
> >       errors.add(:state_id,"Please select a valid state")
> >     else
> >       # go to the next page
> >     end
> >   end
> >
> >
> > But errors is not available in the controller. It''s available
only
> > in the model. I could use flash[:notice] but using errors would
> > have have helped. It would have kept everything consistent with the
> > other error message.
> >
>
> I''m not sure I understand why your controller has to add the error
> message.  Does state_id belong to a model, or is it kind of
> "floating" as unrelated data?
>
> If it belongs to a model, I would do the check inside your model by
> overriding the "validate" method.
>
> e.g.
>
> class User < ActiveRecord::Base
>    def validate
>      if state_id == -1
>        errors.add :state_id, "isn''t valid"
>      end
>    end
> end
>
If you override the validate method, does all the other automagical
validation in the model go away, or does this just add to it?

Thanks,

- Ian

I haven''t tried it yet. Will give it a shot tonight.

The problem is that the model will have validations for page2 too and I
don''t want page2 stuff to be validated while performing the operation
for
page1.

I guess one solution could be to use a dummy model just for page1. Not very
appealing but it might work and each alternative has it''s own kinks.

-=- Neeraj


On 1/11/06, Ian Harding <harding.ian@gmail.com>
wrote:
>
> On 1/11/06, Duane Johnson <duane.johnson@gmail.com> wrote:
> >
> > On Jan 11, 2006, at 9:56 AM, Neeraj Kumar wrote:
> >
> > > I have a wizard which consists of two pages. To keep it simple
> > > let''s say that the first page asks the user to select a
state from
> > > the drop down menu. In case the user doesn''t select any
state, an
> > > error message needs to be displayed.
> > >
> > > Ideally I would like to do something like this.
> > >
> > >   def new
> > >     selected_value = params[:addevent][:state_id]
> > >     if selected_value == "-1"
> > >       errors.add(:state_id,"Please select a valid
state")
> > >     else
> > >       # go to the next page
> > >     end
> > >   end
> > >
> > >
> > > But errors is not available in the controller. It''s
available only
> > > in the model. I could use flash[:notice] but using errors would
> > > have have helped. It would have kept everything consistent with
the
> > > other error message.
> > >
> >
> > I''m not sure I understand why your controller has to add the
error
> > message.  Does state_id belong to a model, or is it kind of
> > "floating" as unrelated data?
> >
> > If it belongs to a model, I would do the check inside your model by
> > overriding the "validate" method.
> >
> > e.g.
> >
> > class User < ActiveRecord::Base
> >    def validate
> >      if state_id == -1
> >        errors.add :state_id, "isn''t valid"
> >      end
> >    end
> > end
> >
>
> If you override the validate method, does all the other automagical
> validation in the model go away, or does this just add to it?
>
> Thanks,
>
> - Ian
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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On Jan 11, 2006, at 11:45 AM, Ian Harding wrote:
>>
>> If it belongs to a model, I would do the check inside your model by
>> overriding the "validate" method.
>>
>> e.g.
>>
>> class User < ActiveRecord::Base
>>    def validate
>>      if state_id == -1
>>        errors.add :state_id, "isn''t valid"
>>      end
>>    end
>> end
>>
>
> If you override the validate method, does all the other automagical
> validation in the model go away, or does this just add to it?
>
Adds to it.

Duane Johnson
(canadaduane)
http://blog.inquirylabs.com/

On Jan 11, 2006, at 11:51 AM, Neeraj Kumar wrote:
> I haven''t tried it yet. Will give it a shot tonight.
>
> The problem is that the model will have validations for page2 too  
> and I don''t want page2 stuff to be validated while performing the
> operation for page1.
>
> I guess one solution could be to use a dummy model just for page1.  
> Not very appealing but it might work and each alternative has it''s
> own kinks.
>
> -=- Neeraj
You can include variables in your model that you use to determine its  
state.  Later, you can check those variables in order to know what  
should be validated.

For example:

class User < ActiveRecord::Base
   attr_writer :steps_completed

   def steps_completed
     @steps_completed || 0
   end

   def validate
     if steps_completed > 0
       # ... validate step 1 ...
     end

     if steps_completed > 1
       # ... validate step 2 ...
     end
   end
end

You can also use conditional validations if you''re using the shortcut  
validators:


class User < ActiveRecord::Base
   attr_writer :steps_completed

   def steps_completed
     @steps_completed || 0
   end

   def after_step_one
     @steps_completed > 1
   end

   validates_presence_of :state_id, :if => :after_step_one
end

Duane Johnson
(canadaduane)
http://blog.inquirylabs.com/