[Twisted-Python] an easy twisted application question

Phil Christensen phil at bubblehouse.org
Tue Nov 11 16:28:55 EST 2003

Okay, that answers another question I had, but I'm still not clear on how
to get at that service object from a couple of places.

For example, here's my Realm implementation:

class InnerSpaceRealm:
    __implements__ = portal.IRealm

    def requestAvatar(self, avatarId, mind, *interfaces):
        if pb.IPerspective in interfaces:
            registry = ### how do i get this?
            avatar = UserPerspective(mind, registry.get(avatarId))
            return pb.IPerspective, avatar, avatar.logout
            raise NotImplementedError("no interface")

what's the right way to get that service object?

this issue comes up again in my UserPerspective class, where i need to
access that registry object during perspective_xxx methods...

there is a part of me that just wants to use registry as a one-off class
with a class variable that returns the current instance, but i don't like
that part ;-).....

thanks again,

>   Newly written programs should implement makeService() instead of
> updateApplication().  As a bonus, purely service-based programs can easily
> and cleanly do things like the above:
>     from twisted.application import service
>     class RegistryService(service.Service):
>         def __init__(self):
>             self.registry = registry.Registry()
>     def makeService(config):
>         s = RegistryService()
>         ...
>         anotherS = SomeotherService()
>         anotherS.setServiceParent(s)  # Or s.setServiceParent(anotherS)
>         ...
>         return s # or return anotherS
>   `s' can be the parent service of other services, in which case it can be
> accessed simply by looking up the parent service, or it could be a child
> service of something else, in which case it would be accessed via a call
> to
> getServiceNamed() on the appropriate parent.
>   This avoids the need for globals and lets services/applications be more
> readily configurable alongside other services/applications (since neither
> will have global state that might interfer with the other).
>   Jp

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