This might not be the best approach but is workable. If we declare these subroutines: 
{
    my $cgi = CGI->new();
    my $session = CGI::Session->new(...);
    my $dbh = $dbh->connect(...);

    sub get_cgi {
        return $cgi;
    }
    sub get_session {
        return $session;
    }
    sub get_dbh {
        return $dbh;
    }
}

[download]
We can then shorten the subroutines' argument lists considerably: 
MAIN: {
    my $result = do_something();

    print get_cgi()->header().$result;
}

sub do_something {
    my $dbh = get_dbh();
    my $cgi = get_cgi();

    $dbh->foo(...);
    $cgi->bar(...);

    my $foo = another_subroutine($somevar, $othervar);

    return final_result($foo);
}

sub another_subroutine {
    my ($somevar, $othervar) = @_;

    return get_dbh()->baz($somevar, $othervar);
}

# and so on

[download]
The other usual options would be wrapping these subroutines inside a class, so you can store the objects in class or instance variables; or making a package or a (singleton?) class whose only purpose is to initialise, store, and return these objects.

In reply to Re: Best practices passing database handles, cgi objects, etc. by Anonymous Monk
in thread Best practices passing database handles, cgi objects, etc. by xtpu2

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