Re^3: Problems getting session management to work: is_expired seems to lie to me

[ted.byers]

I did some digging of my own. Here is what I found.

Function load begins:

sub load {
    my $class = shift;
    return $class->set_error( "called as instance method")    if ref $
+class;
    return $class->set_error( "Too many arguments provided to load()")
+  if @_ > 5;

    my $self = bless {
        _DATA       => {
            _SESSION_ID     => undef,
            _SESSION_CTIME  => undef,
            _SESSION_ATIME  => undef,
            _SESSION_REMOTE_ADDR => $ENV{REMOTE_ADDR} || "",
            #
            # Following two attributes may not exist in every single s
+ession, and declaring
            # them now will force these to get serialized into databas
+e, wasting space. But they
            # are here to remind the coder of their purpose
            #
#            _SESSION_ETIME  => undef,
#            _SESSION_EXPIRE_LIST => {}
        },          # session data
        _DSN        => {},          # parsed DSN params
        _OBJECTS    => {},          # keeps necessary objects
        _DRIVER_ARGS=> {},          # arguments to be passed to driver
        _CLAIMED_ID => undef,       # id **claimed** by client
        _STATUS     => STATUS_UNSET,# status of the session object
        _QUERY      => undef        # query object
    }, $class;

Here we see that _STATUS is part of _DATA. Then, a little further on in load, where it checks for whether or not the session has timed out, we have:

    # checking for expiration ticker
    if ( $self->{_DATA}->{_SESSION_ETIME} ) {
        if ( ($self->{_DATA}->{_SESSION_ATIME} + $self->{_DATA}->{_SES
+SION_ETIME}) <= time() ) {
            $self->_set_status( STATUS_EXPIRED |    # <-- so client ca
+n detect expired sessions
                STATUS_DELETED );                   # <-- session shou
+ld be removed from database
            $self->flush();                         # <-- flush() will
+ do the actual removal!
            return $self;
        }
    }

Which, I believe you quoted. But then in flush, we have:

sub flush {
    my $self = shift;

    # Would it be better to die or err if something very basic is wron
+g here? 
    # I'm trying to address the DESTROY related warning
    # from: http://rt.cpan.org/Ticket/Display.html?id=17541
    # return unless defined $self;

    return unless $self->id;            # <-- empty session
    
    # neither new, nor deleted nor modified
    return if !defined($self->{_STATUS}) or $self->{_STATUS} == STATUS
+_UNSET;

    if ( $self->_test_status(STATUS_NEW) && $self->_test_status(STATUS
+_DELETED) ) {
        $self->{_DATA} = {};
        return $self->_unset_status(STATUS_NEW | STATUS_DELETED);
    }

    my $driver      = $self->_driver();
    my $serializer  = $self->_serializer();

    if ( $self->_test_status(STATUS_DELETED) ) {
        defined($driver->remove($self->id)) or
            return $self->set_error( "flush(): couldn't remove session
+ data: " . $driver->errstr );
        $self->{_DATA} = {};                        # <-- removing all
+ the data, making sure
                                                    # it won't be acce
+ssible after flush()
        return $self->_unset_status(STATUS_DELETED);
    }

    if ( $self->_test_status(STATUS_NEW | STATUS_MODIFIED) ) {
        my $datastr = $serializer->freeze( $self->dataref );
        unless ( defined $datastr ) {
            return $self->set_error( "flush(): couldn't freeze data: "
+ . $serializer->errstr );
        }
        defined( $driver->store($self->id, $datastr) ) or
            return $self->set_error( "flush(): couldn't store datastr:
+ " . $driver->errstr);
        $self->_unset_status(STATUS_NEW | STATUS_MODIFIED);
    }
    return 1;
}

In the block that begins with "if ( $self->_test_status(STATUS_DELETED) ) {", we have "$self->{_DATA} = {};". Doesn't this have the effect of blowing away the "STATUS_EXPIRED" status, resulting in a false value being returned by is_expired because it is checking against a member in the hash that does not exist after the flush when the status has been given a status of DELETED?

Thanks

Ted

[Anonymous Monk]

No, status isn't part of data, see _set_status

[ted.byers]

Sorry, my mistake. I misread it. But then, why does it have an incorrect value once the session expires? All of my colleagues see the same behaviour, in that they always see the session being empty, but they never get the right value from is_expired once the session has expired.

Always, we create the sessions using:

  $session = CGI::Session->new('driver:mysql',$query,{ DataSource  => 
+'dbi:mysql:profitorius',
                              User        => 'rejbyers',
                              Password    => 'Didr39Qcab' });
  $session->expire("5m");

Obviously with different DB credentials and timeout value. And we check it always with something like:

  $session = CGI::Session->load('driver:mysql',$query,{ DataSource  =>
+ 'dbi:mysql:profitorius',
                              User        => 'rejbyers',
                              Password    => 'Didr39Qcab' });
  my $extest = $session->is_expired;

Again, obviously, with different DB credentials. As we always add session parameters, we seem to be able to rely on the session being empty to know the session expired, but we have never been able to get a correct value from is_expired once a session has actually expired. It always returns false to us, when we use it in an actual CGI script. Why?

Thanks.

Ted

[Anonymous Monk]

See Re^5: Problems getting session management to work: is_expired seems to lie to me (cookies)