Guys,
Here's my take on why that "naughty" code is there.
In short:
It is because prior to the first request, no "handler" routine is there yet,
and when the first request is handled, it's not passed as an OO-style call but
as a plain old subroutine call, so no inheritance technique was going to find a
"handler" out of somewhere else.
Example:
One of our Maypole apps is ITSRR::Prism.
<Location /prism >
SetHandler perl-script
PerlResponseHandler ITSRR::Prism
</Location>
Life-cycle of first ever request:
In a just-in-time fashion, ModPerl finds that ITSRR::Prism is not already in
its namespace so it gets automatically 'required' prior handling the first
request.
During the require, the module-level code calls Maypole::setup (via its
inheritance chain) which as we know uses the "naughty" technique to add a
handler entry into the ITSRR::Prism namespace.
Once the require is finished, modperl is finally ready to get this pending
first-ever request dealt with. It calls something like this:
ITSRR::Prism::handler($r) where the $r is an Apache::Request object (note not a
Maypole request!). That call is not an OO-style call.. it's just a call to a
sub out of that package. Therefore no rules about following inheritance chains
to find the method "handler" are going to be applied. So if the naughty bit is
not done, no handler is available to service the request.
If modperl had invoked ITSRR::Prism->handler($r) .. note the arrow technique in
other words a "method" call.. then I suppose the naughty technique would be
unnecessary. I note that modperl does support exactly this if you want, see
http://perl.apache.org/docs/2.0/user/coding/coding.html#Method_Handlers . But
I get the impression from the modperl 1&2 docs that this is unchartered waters
(by me anyway), and requires a special build of modperl.
>>> Peter Speltz <[EMAIL PROTECTED]> 16/09/05 1:57 PM >>>
On 9/15/05, David Baird <[EMAIL PROTECTED]> wrote:
> Maypole::setup() has this:
>
> # Naughty.
> *{ $calling_class . "::handler" } =
> sub { Maypole::handler( $calling_class, @_ ) };
>
> Why is this necessary? $calling_class is the application, which
> already inherits from Maypole.
>
At first I was going to say to safeguard users from messing things up
by defining a handler sub. But it looks like it is so the $r object
in @_ is passed is available and not just the class. I commented it
out and the request could not run. It is really beyond my
understanding now and i could be totally wrong. I am curious though.
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