Re: [Zope-dev] Acquisition, __getattr__ and making a Proxy/Symlink class
> Also, be sure optimize, because __getattr__ gets called *a lot*. In > some cases, I've measured it getting invoked hundreds of thousands of > times in a single request! Ouch! How was that happening? Chris ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Acquisition, __getattr__ and making a Proxy/Symlink class
Lupus Yonderboy writes: > I'm having some troubles trying to develop a > particular zope object and would really appreciate a > bit of help. I'll explain what I'm trying to do: > ... Symbolic Link ... I did not read your lengthy explanation, just got the above keyword There is a "SymLink" product of Shane. Check whether it does what you need. Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Acquisition, __getattr__ and making a Proxy/Symlink class
Lupus Yonderboy wrote: > I have tried hooking __getattr__ and have a hard time > avoiding recursion; I have taken a look at the > ever-productive Shane Hathaway's TransparentFolder > product as well but I think I am let down by my lack > of understanding of the particulars of acquisition. Here are a few hints for avoiding recursion in __getattr__(): - Every attribute __getattr__ accesses that is expected to be in self.__dict__ should also be a class attribute. - Use self.__dict__.get(). - The "self" passed to __getattr__ is *not* wrapped, as it is for other methods, meaning you can't access anything in the object's context from __getattr__. CMF uses a combination of __of__(), volatile attributes, and Zope's threading model to get around this. Also, be sure optimize, because __getattr__ gets called *a lot*. In some cases, I've measured it getting invoked hundreds of thousands of times in a single request! Shane ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Acquisition, __getattr__ and making a Proxy/Symlink class
Lupus Yonderboy wrote: > > Can anyone shed some light on how i might do this? All > objects under the DocumentRoot will be derived from > one of our base classes, so if we need to override > __getattr__ as per TransparentFolders it can be done > easily. Have you looked at the __bobo_traverse__ traversal hook? http://www.zope.org/Documentation/ZDG/ObjectPublishing.dtml -- Steve Alexander Software Engineer Cat-Box limited ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] Acquisition, __getattr__ and making a Proxy/Symlink class
Hi folks,
I'm having some troubles trying to develop a
particular zope object and would really appreciate a
bit of help. I'll explain what I'm trying to do:
What we have is a tree of nodes rooted in a folder
(excuse my ascii art) like so:
+ DocumentRoot (folder)
+ a
+ b
+ c
+ d
+ e
+ e
+ f
+ g
+ X (proxy, pointing to 'e')
Here [a-g] are our node objects, and X is a
proxy-object. The proxy-object is intended to behave a
bit like a sybolic link with a few extra features.
I have looked at Shane Hathaway's Symlink product,
which does the linking job just fine. It allows us to
create a proxy that behaves just like the target, but
we also need the proxy-object to have it's own
attributes and methods.
In the above hierachy, the desired way of finding an
attribute of the proxy 'X' goes something like:
- look in the proxy object ('X')
- if not there look in the proxy target ('e')
- (maybe) if still not found acquire from aq_parent
('g')
- otherwise raise AttributeError
I guess we are wanting X to behave as though it were a
child of the object it links to, so X always behaves
as though it were X.__of__(e) (and possibly also a
child of g, ((X o g) o e) or ((X o e) o g) if not too
complicated).
I have tried hooking __getattr__ and have a hard time
avoiding recursion; I have taken a look at the
ever-productive Shane Hathaway's TransparentFolder
product as well but I think I am let down by my lack
of understanding of the particulars of acquisition.
Can anyone shed some light on how i might do this? All
objects under the DocumentRoot will be derived from
one of our base classes, so if we need to override
__getattr__ as per TransparentFolders it can be done
easily.
Cheers
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