--- Clinton Gormley <[EMAIL PROTECTED]> wrote:
> > we are exploring the idea of writing medium to
> large
> > Perl apps in the future which will require
> mod_perl.
> > the current environment is apache 1.3. having
> read
> > modperl's doc and i am concerned about running
> > multiple unrelated mod_perl apps on one server,
> such
> > as 2 or 3 medium Perl apps. ( issue like database
> > handler pollution etc which i know little about )
> >
>
> The only place where you would have an issue with
> running multiple
> applications within one server (even if distributed
> across virtual
> servers) is where :
> - you have a common module that is used by more
> than one application
> - that module has the concept of a single set of
> configuration data
> rather than a per-application set
>
> Not very clear, so let me give an example.
>
> If, for example, you were to have a module called
> My::Template, that is
> used by 5 different applications.
>
> My::Template stores the path to the templates in the
> package wide
> variable $template_path.
>
> As each application sets its own template_path, it
> overrides the setting
> from the application before.
>
> The ways to avoid this are:
> * you pass the template path in to My::Template
> every time you call it
>
> process_template ($template_path,
> $template_name, $data)
>
> * you create a My::Template object which, amongst
> other things, has
> the template path as a property
>
> $t = My::Template->new();
> $t->template_path($path);
> $t->process_template($template,$data);
>
> * for classes which inherit from My::Template,
> instead of using a
> scalar $template_path, you use a hash, which has
> the class of the
> calling object as the key, and that classes
> template path as the
> value
>
> package My::Template;
>
> my %Template_Path;
>
> sub template_path {
> my $self = shift;
> my $class = ref $self || $self;
> if (@_) {
> my $path = shift;
> $Template_Path{$class} = $path};
> }
> return $Template_Path{$class}
> }
>
>
> Another example of things with global effects is the
> current working
> directory. CWD is global, and thus you cannot rely
> on it staying the
> same. The safest way to handle this is to just use
> absolute filenames.
thanks! I actually have an example of this. A module
for event logging purpose. the global variable is a
hash consists a set of default log flags corresponding
to log messages.
i can register a new flag/msg to the global variable
in my app and go on with the logging. a simplified
version :
package EventLogging;
my %EVENT_TYPES = ( log_in_ok => 'Login OK', .. );
sub add_event {
my ($self, $your_event) = @_;
while ( my ($k, $v) = each %$your_event ) {
$EVENT_TYPES{ $k } = $v;
}
}
use EventLogging;
my $elog = EventLogging->new()
$elog->add_event({...});
now under mod_perl with few apps sharing the same
module, what's the best way to solve this problem ?
mod_perl has an excellent document. but is there a
checklist kind of thing for running mod_perl in
environment like this? where can i read more about
this?
> hth
>
> Clint
>
>
thanks,
James.
____________________________________________________________________________________
Finding fabulous fares is fun.
Let Yahoo! FareChase search your favorite travel sites to find flight and hotel
bargains.
http://farechase.yahoo.com/promo-generic-14795097
