On Tue, 13 Jun 2000, Erich L. Markert wrote:
> I'm trying to figure out the best way to make apps (un)available without
> having to edit the apache config files.
We did something like this by making a handler like this:
package Foo::PerlHandler;
use Class::MethodMaker
new_with_init => 'new',
get_set => [qw/request/];
sub handler {
my ($class, $r) = @_;
($class, $r) = (__PACKAGE__, $class) unless defined $r;
if (-f /tmp/foo.unavailable) {
$r->headers_out->add('Location', '/maintenance/index.html');
return REDIRECT;
}
my $this = $class->new($r);
$this->service;
}
sub init {
my ($this, $r) = @_;
$this->request($r);
}
sub service {
die "service is virtual!\n";
}
__END__
Then in our actual apps, we inherit Foo::PerlHandler:
package Foo::MyApp;
use Foo::PerlHandler;
@ISA = qw(Foo::PerlHandler);
sub handler {
my ($class, $r) = @_;
($class, $r) = (__PACKAGE__, $class) unless defined $r;
# do pre-request things specific to Foo::MyApp
return $class->SUPER::handler($r);
}
sub service {
my ($this) = @_;
my $r = $this->request;
# do whatever here that you would do in your handler.
}
__END__
In httpd.conf:
<Location /foo/myapp>
SetHandler perl-script
PerlHandler Foo::MyApp
</Location>
In actuality, we usually dont have to even define a handler() in our
application classes because the one provided by Foo::PerlHandler does
everything we need. Occasionally it is useful to do overload it though (which
is why I show the simple example above.
The benefit of this is that as long as all of our applications make use of
Foo::PerlHandler as their parent class, then we can shut down all applications
and make them redirect to /maintenance/index.html by simply doing "touch
/tmp/foo.unavailable" on the web server(s). No need to restart, no need to
fiddle with config files.
To make the applications available again, just "rm /tmp/foo.unavailable" and
requests are not redirected to the maintenance page anymore.
Anyways, this is how we decided to deal with this issue. Theres lots of other
ways I am sure :).
Mike
