July 2002 - Zope-Dev

Re: [Zope-dev] Ambiguities in "Inheritance and Class Security Declaration"
by Chris McDonough 21 Jul '02

21 Jul '02

> > I'm sort of stumped as to how the subclass' assertions are applied in > > the absence of InitializeClass! This is not what I expected, I would > > have thought that differing assertions would only be applied if > > InitializeClass was called on the subclass. There's some magic going > > on here that I don't understand. > > The magic is that Persistent has a __class_init__ that calls > InitializeClass for you. (This attribute is actually set by > App.PersistentExtra, called from Globals.) Aha. This is what I was missing! I used to know that, too. ;-) Thanks for clearing it up! - C

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Ambiguities in "Inheritance and Class Security Declaration"
by Ross Boylan 20 Jul '02

20 Jul '02

After reading this section of the development guide, I have a lot of questions (pp 75-76 of the guide). 1. If a subclass redefines a base class method, does the subclass need to do a security declaration on it? The document says "You only need to make security declarations for methods .... your class actually defines. If your class inherits from other classes, the methods of the base classes are protected by the security declarations made in the base classes." The first sentence seems to indicate a security declaration is necessary (since you define the method); the second sentence suggests its not. It depends partly on the meaning of "define" and also "method" (that is, is redefinition considered definition? does method refer to a name or to a specific classes implementation of that name?). 2. Does a subclass need to have security = ClassSecurityInfo() in it if the base class does? Judging from the example, yes. 3. Under what circumstances is the declaration in 2 necessary? For example, only if new method names are introduced and protected? Or any reference to security in the subclass? It seems the latter, from the example. 4. Suppose we wanted to change the security of a base class method without otherwise redefining it. What's necessary then? 5. Under what conditions is InitializeClass necessary for the subclass when the base class has been through InitializeClass? (The guide only addresses the case when the base class has not been so processed. It also says the declarations "filter down", but the implication of this for new method is unclear.) This section has a lot of explicit discussion of odd cases (no security in superclass, redefining permissions on existing methods without changing them) and not enough about the normal cases (my subclass extends some base class methods and defines some new ones). Also, the second paragraph uses "superclass" where I hope it means subclass. Although I would appreciate and responses from the list, I would also like to send these comments to the documents authors. Unfortunately, I see no authorship or contact information in the document. Can anyone suggest some? Thanks.

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Re: [Zope-dev] Leak in 2.5.1 cAccessControl.c !?
by Stefan H. Holek 20 Jul '02

20 Jul '02

Could be. ;-) Does your problem go away when you put export ZOPE_SECURITY_POLICY=PYTHON in your start script? Mine did. I would otherwise not have suspected cAccessControl. Stefan --On Donnerstag, 18. Juli 2002 13:28 -0700 Charlie Reiman <creiman(a)kefta.com> wrote: > Could this be related to the collector issue I already filed? > > http://collector.zope.org/Zope/421 > -- Those who write software only for pay should go hurt some other field. /Erik Naggum/

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How to concatenate ID + string to check for object?
by EvH 20 Jul '02

20 Jul '02

Hi, I've done my homework before posting, but can't find a way out: When adding articles to my intranet, if an icon exists (eg. if it's an article about Zope, I added the Zope icon to ZODB), I will display it in a corner; If no icon exists for this article, I'll display a default icon to avoid having an empty "IMG" box. I've tried multiple things, but none work. Here's the latest trial: //Zope complains that the first line below is NOK <dtml-if expr="<dtml-var id>+'.png'"> <img src="<dtml-var id>.png" border=0> //To check that concatenating both strings works <dtml-var id>.png <dtml-else> <img src="default_icon.png" border=0> <dtml-var id>.png </dtml-if> Any idea? Thx EvH.

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Re: [Zope-dev] Leak in 2.5.1 cAccessControl.c !?
by Charlie Reiman 19 Jul '02

19 Jul '02

Hmm. It appears the script modification did not fix the problem, but patching the source did. So you have my blessing to use collector issue 421 if you want to justify your checkin and drop the bug count by one. Thank you! > -----Original Message----- > From: Stefan H. Holek [mailto:stefan@epy.co.at] > Sent: Friday, July 19, 2002 1:39 AM > To: Charlie Reiman > Cc: zope-dev(a)zope.org > Subject: Re: [Zope-dev] Leak in 2.5.1 cAccessControl.c !? > > > Could be. ;-) > > Does your problem go away when you put > export ZOPE_SECURITY_POLICY=PYTHON > in your start script? > > Mine did. I would otherwise not have suspected cAccessControl. > > Stefan > > > --On Donnerstag, 18. Juli 2002 13:28 -0700 Charlie Reiman > <creiman(a)kefta.com> wrote: > > > Could this be related to the collector issue I already filed? > > > > http://collector.zope.org/Zope/421 > > > > -- > Those who write software only for pay should go hurt some other field. > /Erik Naggum/ >

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Nesting Forms
by Ross Boylan 19 Jul '02

19 Jul '02

I have a product with a number of classes that have subclasses. It seems natural to make the screens for the subclasses by extending those of the superclass. Can anyone suggest a good way to do that? The naive approach is that I have a manage_edit_A.dtml that gives a management screen for A. If B subclasses A, I create manage_edit_B.dtml by copying from the first file and then fiddling with it. Obviously, it would be desirable for a change in A to only require changing a single file. I would prefer a more elegant approach. Perhaps I can define some method in A that the dtml will reference, and then B can override the method to add some extra stuff (the method would return a DTML snippet). First, I'm not exactly sure how to pick up the method from the DTML. Second, I'm not sure if this is the best solution. For one thing, I would prefer to keep all my dtml in separate files, rather than defining it into my methods. Any suggestions? P.S. I'd like to thank Toby Dickenson, Casey Duncan, and R. David Murray for their very helpful responses to my previous question.

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BitTorrent
by Shane Hathaway 19 Jul '02

19 Jul '02

BitTorrent is an interesting, new, open source project. It enhances Internet file downloading with peer-to-peer ideas, taking a lot of the burden off the central server. I tried it out last night. What I didn't know until after I had downloaded it is that BitTorrent is written in pure Python! It integrates with the browser in the same way as ExternalEditor does, with a special mime type that launches BitTorrent. The client is relatively easy to install and very easy to use. http://bitconjurer.org/BitTorrent/ It would be cool to see a Zope product that takes advantage of this. It would be very simple--it would allow users to download anything in Zope via BitTorrent. Say you have a file at: http://zope.example.com/linux/kernels/kernel-2.4.19.tar.gz You could point your users at the following URL and have everything "just work": http://zope.example.com/linux/kernels/kernel-2.4.19.tar.gz/torrentify It would take a huge burden off your server. Anyone interested? I shouldn't take this on myself, but I'd happily help someone out! Shane

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bad bare except in PageTemplateFile.py
by Steve Alexander 19 Jul '02

19 Jul '02

lib/python/Products/PageTemplateFile.py, line 110, method _cook_check try: mtime=os.stat(self.filename)[8] except: mtime=0 I've just spent an hour or so tracking down an awkward bug in some unit-tests. The true error was being hidden by this bare except. I'd change it, and commit the change, except that I don't know what it is supposed to be catching. Any hints? Actually, I'd rather just remove the try: except: and let os.stat fail if it is going to fail. Any objections? (of course there will be... even bare excepts were put there for some reason...) -- Steve Alexander

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Fw: [Zope-dev] Nesting Forms
by Adrian Hungate 19 Jul '02

19 Jul '02

Ooops, I meant this to go to the list as well... Adrian... ----- Original Message ----- From: "Adrian Hungate" <adrian(a)haqa.co.uk> To: "Ross Boylan" <RossBoylan(a)stanfordalumni.org> Sent: Friday, July 19, 2002 8:40 AM Subject: Re: [Zope-dev] Nesting Forms > Although I would probably avoid what you are trying to do, it doesn't seem > that hard. Here is how I would do it (Which I think is just an extension of > the other sugestions here). > > Have one base class which contains (For example class _base) > * a method to produce an empty, or almost empty, page - All classes will > override this. > * a DTML Method which contains "header", "form start", a call to the method > above, "form buttons", "form end", "footer". No classes will override this. > > Then each desendant class would work something like (e.g. class A(_base) ) > * Override the method, get the HTML returned by _base.method() and add your > new HTML to it. > * Do not override the DTML Method.... > > All descendants of A could do the same by adding their own HTML onto the end > of A.method() etc... > > This should work (And could be repeated for as many screens as there are in > the product), because the <head></head>, <body></body> and <form></form> > elements are NOT part of the HTML returned by the base class method, so the > ordering should be correct. > > Of course, you will need to do the same with the form handler functions, but > that is basic python, and all products do that without thinking. > > I hope this is clearer to you than it is to me now I am re-reading it. :) > > Adrian... > > -- > Adrian Hungate > EMail: adrian(a)haqa.co.uk > Web: http://www.haqa.co.uk > > ----- Original Message ----- > From: "Ross Boylan" <RossBoylan(a)stanfordalumni.org> > To: "Dieter Maurer" <dieter(a)handshake.de> > Cc: "Ross Boylan" <RossBoylan(a)stanfordalumni.org>; <zope-dev(a)zope.org> > Sent: Friday, July 19, 2002 6:38 AM > Subject: Re: [Zope-dev] Nesting Forms > > > > On Thu, Jul 18, 2002 at 08:41:02PM +0200, Dieter Maurer wrote: > > > Ross Boylan writes: > > > > ... > > > > I would prefer a more elegant approach. Perhaps I can define some > > > > method in A that the dtml will reference, and then B can override the > > > > method to add some extra stuff (the method would return a DTML > > > > snippet). > > > That sounds good. It is how the ZMI works... > > > > ZMI = Zope Management Interface (i.e., in the core app), or is this > > something else? At any rate, I'm not sure what you're referring to, > > or where to look. > > > > > > > > > First, I'm not exactly sure how to pick up the method from the DTML. > > > There are two cases: > > > > > > * view of an existing object > > > > > > then the object is the client of the primary view. > > > Make all you snippets attributes of the object > > > and you can simply access them by name. > > > > > > The ZMI does this. If necessary, look how it does. > > > > The problem isn't just accessing them, but combining them. Say C is a > > subclass of B is a subclass of A. Each subclass has the entire user > > interface of its base class (aka superclass) and some extra stuff. > > > > Either each class implements its novel stuff with a unique name. In > > that case, I still have to make a separate dtml file for each, > > referencing the appropriate names (though your suggestion below helps > > on that). > > > > Or each has the same name. Then the problem is how to get the > > subclasses method to return its unique stuff plus everything in its > > base class. For vanilla methods that's not a big deal, but if each is > > a DTMLFile, I don't think it will work. More about that at the very > > bottom. > > > > > > > > * object creation form > > > > > > That's much more difficult. ZMI does not reuse fragments for > > > this case. > > > > > > There is a partial solution for DTMLFiles, but it is not nice > > > and restricted to DTML. > > > > > > "DTMLFile" constructors accept a dictionary with default > > > name bindings. This way, you can customize your > > > DTMLFile with different bindings according to context, > > > e.g. > > > > > > addAForm= DTMLFile('dtml/addForm', globals(), > > > comp1= AComp1 > > > comp2= AComp2 > > > ...) > > > addBForm= DTMLFile('dtml/addForm', globals(), > > > comp1= BComp1 > > > comp2= BComp2 > > > ...) > > > > This suggests one semi-refined strategy: the file defines the maximal > > interface, and then parts of it are guarded by <dtml-if ... > tests on > these > > extra variables I pass in. I could even pass the class in, but I > > suppose if I try to do issubclass(PassedInClass, MyApplicationClass) > > in the dtml-if I will find that I lack security to access > > PassedInClass, issubclass, or MyApplicationClass. > > > > > > > > > > > Second, I'm not sure if this is the best solution. For one thing, I > > > > would prefer to keep all my dtml in separate files, rather than > > > > defining it into my methods. > > > You can have separate files and do something like: > > > > > > class YourProduct: > > > .... > > > mySnippet= DTMLFile('dtml/mySnippetFile',globals()) > > > .... > > > > > > > The problem comes if I stick the different interface segments in > > different files, so A.dtml has the user interface for A and B.dtml has > > just the added interface for B, a subclass of A. But I want the user > > interface for B to be the combination of the A and B parts. > > > > > > > > Dieter > > > > > > > > > _______________________________________________ > > Zope-Dev maillist - Zope-Dev(a)zope.org > > 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 ) > > >

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adding custom products programmatically
by Kaimar Karu 19 Jul '02

19 Jul '02

Hi, I created a new Product, "GalahadFile" and in it I created several Z Classes, GalahadImageFile for example. Now if i want to use python script to add a GalahadImageFile programmatically - what should I do? I add Image files this way: context.galahad.file_storage[str(org_id)].manage_addImage(str(new_id), file=new_contents, title=new_title) and I want to add GalahadImageFiles this way: context.galahad.file_storage[str(org_id)].manage_addGalahadImageFile(str(new_id), file=new_contents, title=new_title) What should I do for this? What methods should I add and where for this "manage_addGalahadImageFile" to work? TIA, Kaimar

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