Rails - Mar 2005 - Performing validations without saving

I am working on the authentication part of my application first and
the login generator and has been helpful. My application requires the
users to ''activate'' existing accounts by supplying their email
address
and a password. The email address is matched against email addresses
already in the database and if found, the password is updated and a
flag is set to indicate that the account has been activated.

My view has fields for email, password and password confirmation. The
user model has validations for length of password etc.

The view also has <%= error_messages_for ''user'' %> to
display validation errors.

For the longest time, I couldn''t figure out why this line would cause
the undefined method `errors'' for nil:NilClass error. Turns out the
error object is returned by the .save method when it applies
validations before saving the user object.

Since I only save changes if I find a match for the email in my users
table, if a match isn''t found, the user isn''t saved and hence
the
validations aren''t and no error object is returned which causes the
error_messages_for line to throw an error.

So the question is: How can I run validations against the parameters
passed from the page without initializing the user object with the
parameters and saving the object?

I''m not sure of this is what you mean but the valid? method runs
validations on a model without saving it:

http://rails.rubyonrails.com/classes/ActiveRecord/Validations.html


On Wed, 30 Mar 2005 23:17:27 -0500, H M
<airmalik-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I am working on the authentication part of my application first and
> the login generator and has been helpful. My application requires the
> users to ''activate'' existing accounts by supplying their
email address
> and a password. The email address is matched against email addresses
> already in the database and if found, the password is updated and a
> flag is set to indicate that the account has been activated.
> 
> My view has fields for email, password and password confirmation. The
> user model has validations for length of password etc.
> 
> The view also has <%= error_messages_for ''user'' %>
to display validation errors.
> 
> For the longest time, I couldn''t figure out why this line would
cause
> the undefined method `errors'' for nil:NilClass error. Turns out
the
> error object is returned by the .save method when it applies
> validations before saving the user object.
> 
> Since I only save changes if I find a match for the email in my users
> table, if a match isn''t found, the user isn''t saved and
hence the
> validations aren''t and no error object is returned which causes
the
> error_messages_for line to throw an error.
> 
> So the question is: How can I run validations against the parameters
> passed from the page without initializing the user object with the
> parameters and saving the object?
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Alan,

Thanks! That''s exactly what I was looking for.

Hammed

On Thu, 31 Mar 2005 07:51:01 +0100, Alan Bullock
<liststuff-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I''m not sure of this is what you mean but the valid? method runs
> validations on a model without saving it:
> 
> http://rails.rubyonrails.com/classes/ActiveRecord/Validations.html