July 2002 - Zope-Dev

How to override __getattr__ and not break acquisition
by Erik A. Dahl 17 Oct '02

17 Oct '02

Ok I need to override __getattr__ in one of my product classes. I'm sure this is killing acquisition but not sure about the persistence stuff (I think this is working). Is there a way to make this work? Here is what I'm doing: def __getattr__(self, name): if name == 'myattr': return self.myattr() I assume that somewhere in the Acquisition code there is a __getattr__ but I can't find it. I tried calling Implicit.__getattr__ but its not there. If some one has an example that would be great. -EAD

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Refresh trashes acquisition
by Gary Speer 14 Aug '02

14 Aug '02

Dear Ross - I strongly encourage you to switch to the zope(a)zope.org mailing list as this one is dedicated to next-generation product enhancement as opposed to peer user assistance. The approach you are taking seems a bit convoluted and I, for one, do not understand the business/project objectives reason to construct the objects as you do and create the acquisition cvhallenge you hope to solve. Perhaps you can elaborate on the goal you hope to accomplish so others can suggest the better tools and object containment structure to use. It seems earlier design decisions have taken you to solving issues that might not exist with an alternative, more-naturally-zope-like approach. Gary Message: 2 Date: Wed, 24 Jul 2002 13:05:59 -0700 To: "Matthew T. Kromer" <matt(a)zope.com> Cc: Ross Boylan <RossBoylan(a)stanfordalumni.org>, zope-dev(a)zope.org Subject: Re: [Zope-dev] Refresh trashes acquisition From: Ross Boylan <RossBoylan(a)stanfordalumni.org> On Wed, Jul 24, 2002 at 10:38:44AM -0400, Matthew T. Kromer wrote: > Ross Boylan wrote: > > >I find that when I refresh my product it destroys some of the > >containment relationships. Things start failing, and as far as I can > >tell the only recovery is to completely rebuild the object. > > > >This is a big problem, and if anyone could explain what is going on > >and how to avoid it I would appreciate it. > > > >Here is the result of aq_chain before the refresh: > >[<RankQuestion instance at 8dd5620>, > ><OriginalSuborder instance at 8c9f8d8>, <EMailBallot instance at > >8dfc870>, <__FactoryDispatcher__ instance at 8e73770>, > ><ProductDispatcher instance at 83f0618>, <Folder instance at 8d5733 > > > >and after > >[<RankQuestion instance at 8dee2d0>] > > > > > [...] > > > > > > > Hmm, while what you're referring to is "refresh" in the sense of a > product reload, it's important to first state that *no* acquisition is > expected to survive between transactions. > > Each transaction must separately acquire its objects; if you try to pass > wrapped objects between transactions or threads you're going to end up > in trouble. > > Secondly, when a product is refreshed, the extensionclass module will > probably create new base classes for any ExtensionClass derived class > file. I dont *think* you can get much mileage out of knowing the id > (address) of a class now, but be aware that a refresh will likely cause > that address to change. I have seen some bizarre errors where module > "constants" changed because of a reload, and "is" tests broke because > "is" tests the object address. > > None of this is explicitly what you're asking about -- but I think what > you're trying to do is in violation of the "no wrapped objects should be > stored past a transaction boundary" rule. > > However, I may be misreading your question too -- which is why I mention > those two rules above so YOU can see if they make sense in your context. > The first point is definitely relevant, and explains why I am having problems. It's surprising what I'm doing is workign at all! The class redefinition in the second point might explain some of the timing of the problems, but it's the instances, not the classes that I am interested in. The acquisition I want to do is in the object containment hierarchy, but URL of the request will also have this hieararchy. Is there some way I can grab it at the appropriate time? Your comments also clarify a point that was unclear to me from the documentation on acquisition. The documents refers to the object containment hierarchy and the request path hierarchy, and recommend keeping them consistent. But I didn't understand which hierarchy it used if they weren't. Apparently only the request path matters. It may be helpful to say more about the exact relations in my case: [indentation indicates containment in this diagram; capital letters are for objects] B ballot Q1 question R1a response R1b response SR suborder of responses see below for suborders R1a R1b (same objects as the R1's above) Q2 question ... NQ "namestyle" of questions (determines labeling) NR namestyle of responses SQ suborder of questions (sequential, random, ...) this suborder contains a list of the same questions Q1, Q2, etc that the ballot B holds. It also the name of the namestyle, to be acquired from the container. Generally, B and maybe Q will be in my request path, and the other items are not. I ask the suborders for list of items, so they give me back a list of Q's or R's. The items in those lists were the ones I was trying to wrap. At the most extreme case, I get a response R from the suborder list of a question Q, and I get the Q from the suborder of the ballot. So I't two levels removed from my original context, the ballot B, that has the namestyle I'm trying to acquire. The suborder on the Question needs to acquire the namestyle from the Ballot. Finally, I may be making an overly conservative assumption about ObjectManagers. Without it, the suborders would not need to hold onto object references. It's easiest to explain this with a specific example. I want to be able to recover the original order questions were entered into the ballot. Ballot is a subclass of ObjectManager. I believe I am not allowed to make any assumptions about the order its items will be returned by objectItems(), so I am using the suborder to track that. P.S. I also assume that objectItems('type') gets only objects of that type, not subtypes. Does anyone know if that's so? --__--__-- _______________________________________________ Zope-Dev maillist - Zope-Dev(a)zope.org http://lists.zope.org/mailman/listinfo/zope-dev (To receive general Zope announcements, see: http://lists.zope.org/mailman/listinfo/zope-announce For non-developer, user-level issues, zope(a)zope.org, http://lists.zope.org/mailman/listinfo/zope ) End of Zope-Dev Digest

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Memory Leaks
by Andy McKay 07 Aug '02

07 Aug '02

Hey all, A client of mine seems to be plagued with memory leaks. I have a CMF / Plone site on We fixed some security issues that caused a major leak this is the same I believe as http://collector.zope.org/Zope/421, by jiggling settings this no longer an issue. Anyway we are still getting some minor leaks that severly limit the amount of the traffic the box is going to be able take. Lots of different objects are being leaked, including good old DateTime, however I dont believe its this, DateTime just happens to be there. Possible culprits are (trimmed down debug page) ZPT: Products.PageTemplates.Expressions.PathExpr, Products.PageTemplates.Expressions.SubPathExpr, Products.PageTemplates.TALES.TALESError etc... or AccessControl AccessControl.unauthorized.Unauthorized, AccessControl.SecurityManager.SecurityManager etc... A quick rummage through LeakFinder hasn't helped too much so Im not sure what too recommend. Good old install ZEO and restart Zope every few hours? Is anyone else having issues? Configuration: Plone 0.99 "Almost There" CMF Beta 1.3 beta 1 Zope 2.5.1 Python 2.1.3 RedHat Linux 7.1 Using Apache and pcgi to serve... -- Andy McKay

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Refer to zope attribute or object in source
by kent sin 01 Aug '02

01 Aug '02

In PropertySheets.py of zope/lib/python/OFS def xml_escape(v): ..... return unicode(v, "latin-1").encode("utf-8") Are there anyway to substitute the "latin-1" with an attribute of the zope site's attribute say: "zope-charset" which a site maintainer can modify through the web? I raise this question because the current-cvs version of zope is turned into unicode, but all the source everywhere is assumed that the data input is "latin-1" but I am very sure that it will not always the case. Some sites simply don't work in that assumption, turning many sites using zope stop upgrade or stop using zope. This will seriously hurt the zope community. The initial act to make zope understand unicode is to help zope internationalize, but the actual effect was not. I urge the zope developer, the zope coporation as well as product developers (some products like ieDocument and worldPilot have "8859-1" specified in their source) alert on this issue, and take action before it is too late. The best solution I could come up with is to allow individual site manager to choose its default charset and allow other site-branch manager to overwrite it with acquisition, thus the attribute zope-charset will be used to determine both the "Content-type: text/plain; charset="<dtml-var zope-charset>" and the code convertion of Zope like PropertySheets.py __________________________________________________ Do You Yahoo!? Yahoo! Health - Feel better, live better http://health.yahoo.com

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Zope hangs, with processes being idle ... (rather urgent problem)
by Joachim Werner 01 Aug '02

01 Aug '02

Hi! I have a Zope 2.5.1 using ZEO on Linux, with Apache as proxy server. The two ZEO clients run fine for a couple of hours, and then suddenly one of them stops responding. It's the type of Zope hangs when all processes are fine, but ZServer just doesn't respond (load is very low, with the CPU 90% idle, so it is not a performance issue or recursion problem). There is no error before this situation happens. The processes just don't respond any more. The second ZEO keeps running, but that machine also hangs from time to time, so I guess ZEO is not the problem, and the hardware or any Linux-specific problems aren't either. When the ZServer hangs, I can not access it directly, so it is no problem with the Apache. You see, I don't have any clue on what is happening here. The servers worked fine for months, and I don't know what specific change could have caused the problem. How can such a situation be debugged? Cheers Joachim

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Extension class and __init__
by Ross Boylan 28 Jul '02

28 Jul '02

I had the bright idea of defining a mixin class whose methods I thought I could use in my regular Zope product classes: class AMixin: def __init__(self): blah, blah blah class B(AMixin, Persistent, Folder, ....): def __init__(self): # do some of my own stuff AMixin.__init__(self) This fails with the warning (as I recall) that the unbound method AMixin.__init__ needs to be called with an instance as its first argument. (I've stripped the example down to give what I think are the essentials). self in the context of B is an Extension class, and I'm guessing this is making AMixin unhappy because it's not. I assume I'll have the same problem with other methods that I attempt to access using AMixin.foo(self). Can anyone confirm this diagnosis? And what's the best solution? I have redefined things class AMixin: def _mixin_init(self): #stuff class B(AMixin, .....): def __init__(self): #my own stuff self._mixin_init(self) and this seems to work, but I wonder if there's a way to get the classes to play together better (maybe "class AMixin(ExtensionClass):"? though since ExtensionClass is a type I guess that's not exactly it). This was after already discovering that isinstance doesn't work with ExtensionClass (which I see confirmed on the list, along with the fact that ExtensionClass generally has a lot of rough spots and may be on the way out). This is with Zope 2.5.1.

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Re: [Zope-dev] Refresh trashes acquisition
by Gary Speer 26 Jul '02

26 Jul '02

Thanks for your note Steve. I know not to post HTML, this one accidentally slipped by and I noticed as soon as I got the copy back - My apologies to the group!!!! I was trying to assist on what seemed to me to be more of an app design issue instead of a possible bug in the refresh module. It seemed that this was the wrong forum to provide my suggestions until it was determined that it was a bug/zope design issue instead of a misuse/misunderstanding of acquisition or app design issue. Because of that I came out of the lurker shadows to take it to the forum that was appropriate to participate and make application design suggestions in. I had no idea I would start a minor flame war by trying to be helpful. My apologies to the group ... Back to the shadows ... Gary ----- Original Message ----- From: "Steve Alexander" <steve(a)cat-box.net> To: "Myroslav Opyr" <myroslav(a)zope.net.ua>; "Gary Speer" <gspeer(a)cortech.org> Sent: Thursday, July 25, 2002 4:08 PM Subject: Re: [Zope-dev] Refresh trashes acquisition Myroslav Opyr wrote: > > P.S. It is really interesting what X-Spam-Status this message will get > ;) the one of Gary had 3.2 :) Maybe there is a sense to lower threshold > from 5.0 to 3.0 ;) Gary sent his email HTML encoded, which won't have helped the rating. Gary, please don't email HTML encoded mailings to the zope-dev(a)zope.org.list. Thanks. -- Steve Alexander

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Refresh trashes acquisition
by Ross Boylan 24 Jul '02

24 Jul '02

I find that when I refresh my product it destroys some of the containment relationships. Things start failing, and as far as I can tell the only recovery is to completely rebuild the object. This is a big problem, and if anyone could explain what is going on and how to avoid it I would appreciate it. Here is the result of aq_chain before the refresh: [<RankQuestion instance at 8dd5620>, <OriginalSuborder instance at 8c9f8d8>, <EMailBallot instance at 8dfc870>, <__FactoryDispatcher__ instance at 8e73770>, <ProductDispatcher instance at 83f0618>, <Folder instance at 8d5733 and after [<RankQuestion instance at 8dee2d0>] Interestingly, and object inside this retained some context: Before: [<RandomSuborder instance at 8df6248>, <RankQuestion instance at 8dd5620>, <OriginalSuborder instance at 8c9f8d8>, <EMailBallot instance at 8dfc870>, <__FactoryDispatcher__ instance at 8e73770>, <ProductDispatcher instance at 83f0618>, <Folder instance at 8d57330>, <Application instance at 8e44ae0>, <RequestContainer instance at 8ed53e8>] After: [<RandomSuborder instance at 8be7128>, <RankQuestion instance at 8dee2d0>] Notice that the new RandomSuborder instance (new, judging by the address, though it should be the same object) points to the new RankQuestion. Unfortunately, I need to go a little further than that to get the variable I'm looking for :(. It may be relevant that I am explicitly wrapping objects uses a.__of__(b). I did this because I thought things weren't being wrapped at all, but the results above show the problem is different: the wrappers are lost on refresh. The refresh changes nothing structural, just some method code. One thought that occurred to me is that it is not the changes to my product classes that is causing the trouble, but the inclusion of some of the items higher up the chain.

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pending collector issues
by Christian Theune 24 Jul '02

24 Jul '02

Hi. I don't know if this mail comes around a second time today, i had some serious problems with my MTA configurations ... I submitted 4 issues some time ago (ranging from march to june) but never got any response. I don't think that they are totally uninteresting to not at least get a "no we won't care about them" as a response. I would be glad if somebody who does the daily collector maintenance could take a look at those issues: 269, 407, 418, 460 Thanks in advance Christian -- Christian Theune - ct(a)gocept.com gocept gmbh & co.kg - schalaunische strasse 6 - 06366 koethen/anhalt tel.+49 3641 511586 - fax.+49 3496 3099118 mob. - +49 179 7808366 reduce(lambda x,y:x+y,[chr(ord(x)^42) for x in 'zS^BED\nX_FOY\x0b'])

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Folder(id)
by Florent Guillaume 24 Jul '02

24 Jul '02

Currently OFS.Folder.Folder doesn't have a constructor, so (I think) defaults to that of ExtensionClass.Base which accepts anything. The problem is that a number of places in the code, and a number of people, expect ob=Folder(id) to create a correct folder, whereas the id is actually not used. Noa got bitten by this today, and a number of tests even call Folder with an argument. Whereas the rest of the code painstakingly does ob = Folder() ob.id = id Is anyone opposed to having a def __init__(id=None, title=None): if id is not None: self.id = id if title is not None: self.title = title in Folder ? Florent -- Florent Guillaume, Nuxeo (Paris, France) +33 1 40 33 79 87 http://nuxeo.com mailto:fg@nuxeo.com

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