(z) SUPER and Class::DBI

zigdon has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I thought I understood how SUPER works - but today I tried to override a method in a CDBI object, and things didn't happen as I expected.

I have a My::User.pm, which (among other columns), has a Password column. Since I'm hashing the password, I wanted to able to call $u->password("secret"), and have it stored in the database automatically hashed. So in my User.pm module, I tried to override the password method:

sub password {
  my $self = shift;

  if (@_) { # we're setting a value
    $_[0] = Digest::MD5::md5_base64($_[0]);
  }

  return $self->SUPER::password(@_);
}
[download]

But when I try this, I get the following error:

Can't locate object method "password" via package "My::User" at My/Use
+r.pm line 37.
[download]

So I have two questions:

What am I doing wrong with the SUPER call?
I'm sure this can be done with triggers - is "before_set_password" the only one I need to set?

Thanks!

-- zigdon

Comment on (z) SUPER and Class::DBI Select or Download Code

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Re: (z) SUPER and Class::DBI
by edoc (Chaplain) on Dec 30, 2003 at 22:10 UTC

mm.. can't find the reference I've read but basically..

In CDBI your column accessors are dynamically created, not inherited from another class so when you override a method, then it's gone and there is no SUPER::method.

In this instance you probably want to use the basic set method:

  # ...
  return $self->set(password => $_[0]);
[download]

cheers,

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Re: (z) SUPER and Class::DBI
by duct_tape (Hermit) on Dec 30, 2003 at 22:27 UTC

I believe that SUPER:: isn't going to work because that would be trying to call the password method from whatever your class is inheriting from. ie: Class::DBI. (not 100% positive on that). Since the password method is going to exist in your current package, you are overwriting it and SUPER:: will not work.

CDBI uses Class::Accessor to handle the accessor/mutator creation. When it creates an accessor it creates an alias to it called _WHATEVER_accessor. So you can do this instead:

return $self->_password_accessor(@_)

However that this will not work when using create or find_or_create. Only for modification. I would go for the trigger option instead. If you are going to use triggers you can use before_create and before_set_password.

The one other method you can do is create a class for the passwords, and then set a has_a relationship for the password column. Since this is a fairly simple task, that may be overkill. But it is something to think about.

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Re: (z) SUPER and Class::DBI
by PodMaster (Abbot) on Dec 31, 2003 at 07:08 UTC

DATA NORMALIZATION

DATA VALIDATION

Class::DBI

MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"
I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).
** The third rule of perl club is a statement of fact: pod is sexy.

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(z) Re^2: SUPER and Class::DBI

by zigdon (Deacon) on Dec 31, 2003 at 13:52 UTC

exactly

sub normalize_column_values {
  my $self = shift;
  my $hashref = shift;

  if (exists $hashref->{password}) {
    $hashref->{password} = Digest::MD5::md5_base64($hashref->{password
+});
  }
}
[download]

-- zigdon

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Re: (z) SUPER and Class::DBI
by sgifford (Prior) on Dec 30, 2003 at 21:50 UTC

What you've got looks OK to me on its own. Perhaps it's something else in your class?

What's in your @ISA array? Is your package declaration right? Is your reference blessed correctly? Can you post more of your module, especially the declarations that make it work like an object?

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(z) Re^2: SUPER and Class::DBI

by zigdon (Deacon) on Dec 31, 2003 at 13:45 UTC

Here's the relevatn declarations:

package My::User;
use base 'My::DBI';
Library::User->table('Users');
Library::User->columns(All => qw/UserID Email Password/);
[download]

-- zigdon

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