User::Simple - Simple user sessions management

  $usr = User::Simple->new(db => $db,
                           [tbl => $user_table],
                           [durat => $duration],
                           [debug => $debug]);

  $ok = $usr->ck_session($session);
  $ok = $usr->ck_login($login, $passwd, [$no_sess]);
  $ok = $usr->set_passwd($new_pass);
  $usr->end_session;

  $id = $usr->id;
  $session = $usr->session;

  $otherattrib = $user->otherattrib
  $ok = $user->set_otherattrib($value);

User::Simple provides a very simple framework for validating users, managing their sessions and storing a minimal set of information (this is, a meaningful user login/password pair, and privilege level) via a database, while providing a transparent way to access any other attributes you might define. The sessions can be used as identifiers for i.e. cookies on a Web system. The passwords are stored as MD5 hashes (this means, the password is never stored in clear text).

User::Simple was originally developed with a PostgreSQL database in mind, but should work with any real DBMS. Sadly, this rules out DBD::CSV, DBD::XBase, DBD::Excel and many other implementations based on SQL::Statement - The user table requires the driver to implement primary keys and NOT NULL/UNIQUE constraints.

The functionality is split into two modules, User::Simple and User::Simple::Admin. This module provides the functionality your system will need for any interaction started by the user - Authentication, session management, querying the user's data, changing the password and changing any attributes you define not beginning with CWadm_. Note that you cannot directly modify a user's login, session or session expiry from within this module - Just as a general principle, avoid changing logins. If you absolutely must, use User::Simple::Admin instead ;-)

In order to create a User::Simple object, call the new argument with an active DBI (database connection) object as its only argument:

  $usr = User::Simple->new(db => $db, [tbl => $table], [durat => $duration],
                           [debug => $debug]);

Of course, the database must have the right structure in it - please check User::Simple::Admin for more information.

The CWtbl parameter is the name of the table where the user information is stored. If not specified, it defaults to 'user_simple'.

CWdurat is the number of minutes a user's session should last. Its default is of 30 minutes.

CWdebug is the verbosity level of the debugging messages - The default is 2, it accepts integers between 0 and 5 (higher means more messages). Messages of high relevance (i.e. the database failing to reflect any changes we request it to make) are shown if debug is >= 1, regular failure messages are shown if debug >= 3, absolutely everything is shown if debug == 5. Be warned that when debug is set to 5, information such as cleartext passwords will be logged as well!

Once the object is created, we can ask it to verify that a given user is valid, either by checking against a session string or against a login/password pair::

  $ok = $usr->ck_session($session);
  $ok = $usr->ck_login($login, $passwd, [$no_sess]);

The optional CW$no_sess argument should be used if we do not want to modify the current session (or to create a new session), we want only to verify the password matches (i.e. when asking for the current password as a confirmation in order to change a user's password). It will almost always be left false.

To end a session:

  $ok = $usr->end_session;

To verify whether we have successfully validated a user:

  $ok = $usr->is_valid;

To check the user's core attributes (login and ID):

  $login = $usr->login;
  $id = $usr->id;

You might add extra columns to the User::Simple table in your database - You will still be able to query for them in the same way:

  $otherattrib = $user->otherattrib;

i.e.:

  $name = $user->name
  $login = $usr->login;

Note that 'name' and 'level' were core attributes until User::Simple version 1.0 - In order to keep User::Simple as simple and extensible as possible, they became extended attributes. You should not have to modify your code using CWUser::Simple anyway, as changes are transparent. Some minor API changes do happen in CWUser::Simple::Admin, though.

Extended attributes are not checked in any way by User::Simple, they are just stored in the database just as they are received - Some DBDs might not even verify they are of the correct data type. As always, if you want to ensure consistence, use a real RDBMS.

Of course, beware: if the field does not exist, User::Simple will raise an error and die just as if an unknown method had been called.

To change the user's password:

  $ok = $usr->set_passwd($new_pass);

Note that an empty password will not be accepted.

To change any attribute defined by you and not labeled as for administrative use (this is, its name does not start with CWadm_):

  $ok = $usr->set_otherattrib($new_value);

Date::Calc

Digest::MD5

DBI (and a suitable DBD backend)

User::Simple::Admin for administrative routines

Gunnar Wolf <gwolf@gwolf.org>

Copyright 2005 Gunnar Wolf / Instituto de Investigaciones Economicas UNAM This module is Free Software, it can be redistributed under the same terms as Perl.