On Sat, Jan 18, 2020 at 7:48 AM sebb <seb...@gmail.com> wrote:
>
> On Sat, 18 Jan 2020 at 12:39, Sam Ruby <ru...@intertwingly.net> wrote:
> >
> > On Fri, Jan 17, 2020 at 5:10 PM sebb <seb...@gmail.com> wrote:
> > >
> > > I'm not sure what is the purpose of the weak references when applied
> > > to instances of the LDAP class.
> > >
> > > Why does an instance not use hard references so that they last for the
> > > life of the instance?
> >
> > Passenger applications like the roster tool, the secretary workbench,
> > and board agenda tool can stay up for hours or even days. See:
> > https://whimsy.apache.org/status/passenger
>
> I see.
>
> > After every request, every hard reference will go away, enabling the
> > object to be garbage collected.
>
> I don't follow.
>
> If the hard references go away, then surely the objects can be
> garbage-collected?
ASF::LDAP is a module. It only goes away when the process exits.
Classes that inherit from ASF::LDAP base have a class instance
variable which contain a collection of instances. Class instance
variables go away when the process exits.
A common pattern in both CGI scripts and passenger application within
Whimsy is to fetch everything you might need, ideally within one LDAP
request. Maintain a hard reference on that collection, but don't
necessarily pass those objections around the application. Methods
that you call that seek to find instances of those collections will
resolve to the same instance, by that I mean that
ASF::Person.find('rubys') will always return the same object, not
merely another object with the same values for attributes. So if I've
already fetched, for example, public_name, it will be returned without
another round trip to LDAP.
> > What this generally means is that a
> > request will have a consistent view of LDAP, and new requests will get
> > fresh data.
>
> Understood.
>
> > - Sam Ruby
- Sam Ruby
