March 2002 - Zope-Dev

Putting a list of objects into the current namespace (or something)
by Max M 12 Mar '02

12 Mar '02

I am trying to create a "virtual" folder. It should get a list of objects from somewhere else ie. a Catalog query and then act as if the objects exists in that folder. If the objects existed in this structure: / Members/ member1/ doc1 doc2 member2/ doc3 doc4 I want to show the objects in a new context, like: / news/ doc1 doc3 articles/ doc2 doc4 So an url like "/news/doc1" should actually show doc1 from "/Members/member1/doc1" transparently. Has anybody got any pointers as to how I could do this best ? My idea is either to subclass ObjectManager and overwrite "__getitem__()", or to find a way to push my objectlist onto the request object. Any better ideas? Pointers to code that does something similar? regards Max M

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variables in zope (beginner question)
by Mike Guerrero 12 Mar '02

12 Mar '02

Hello, I the code below I want to be declare a variable 'tot_net_amt' and add 'net_amt' to it for each record returned. How can I: 1) declare the variable 2) add to it within the loop. Thanks. Is it in the Zope book? I'll read some more tonight. Thanks for your help. Mike <dtml-var standard_html_header> <h3>Current Month</h3>  <table border="1" cellspacing="0"> <tr> <th><font size="1">Sales Order No.</font></th> <th><font size="1">Net Amt.</font></th> </tr> <dtml-in sql_curr_month_decom> <tr>  <td align="center"><font size="1"><dtml-var sales_ord_no></font></td> <td align="center"><font size="1"><dtml-var net_amt></font></td> </tr> </dtml-in> </table> <dtml-var standard_html_footer>

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Zope 2.4.4b1 and Python 2.1.2 crash again
by Stefano Noferi 12 Mar '02

12 Mar '02

Hi, With zope 2.4.4b1 and python 2.1.2 my system auto-restart (crash) running python script again.. It's the Restricted Python problem resolved? Thanks Stefano ---------------------------------------------------------- Stefano Noferi n o z e S.r.l. Soluzioni Open-Source Via Caduti del Lavoro, 32 56122 Pisa (PI) - Italy Tel: +39 (0)50 533320 Fax: +39 (0)50 526604 Email: stefano(a)noze.it Web: http://www.noze.it ----------------------------------------------------------

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Underscore trouble.
by Romain Slootmaekers 12 Mar '02

12 Mar '02

Yo, We have to connect to an existing database from zope. In this database, some of the fieldnames start with an underscore (fi _url). Zope sees these as protected and raises an exception when we try to access the tables with a select... Is there a way to disable this Zope 'feature' on ZMySQL methods ? TIA, Sloot.

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setPermissionDefault not working???
by Sidnei da Silva 11 Mar '02

11 Mar '02

Hello everyone, Im writing to this list cause i talked with Andreas Jung and it told me to do so. Im having a problem with the method setPermissionDefault, as stated on issue 275 of the Zope collector, http://collector.zope.org/Zope/275, and Andreas told me that he was too busy to take a look at that, so im wondering if anyone is free to take this issue and solve it ASAP. The problem is that setPermissionDefault, when used from a simple Folder based python product is not working at all. There is a sample class attached to the collector issue which i have tested and confirmed not to work. thanx. []'s -- Sidnei da Silva X3ng Web Technology sidnei(a)x3ng.com.br

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Transaction Bugs
by kapil thangavelu 11 Mar '02

11 Mar '02

I wrote some unittests to investigate some odd transaction behavior i noticed while doing unittests of integrating non sub transaction aware objects, and to insure proper txn behavior. these tests test the transaction system independent of the rest of the zodb and test failure modes as well. i've found a few bugs. 1. TM.py ignores calls to tpc_abort. this i believe is the likely cause of most of the rdbms integration problems that are referenced above as TM.py generally forms the integration point between db adapters and zope's transaction framework. if an error occurs in the two-phase-commit protocol, the database adapter will never recieve a finish/commit or abort message, and will therefore (due to how TM works) never be able to register again for a zope transaction. 2. A Non Sub Transaction aware object (including any TM derived object) that participates in a sub-transaction will recieve a tpc_finish message (which for TM derivatives calls _finish) as part of the subtransaction commit process. this means that if the outer transaction is latter aborted, there will be a loss data integrity. 3. As part of the commit process for a transaction involving subtransactions, any objects registered since the last subtransaction commit will be involved in an implicit subtransaction commit. if an error occurs during this implicit subtransaction, none of the objects registered previously to the last explicit subtransaction commit will recieve any messages. i'm not sure totally sure this is a bug since any calls to explicitly begin a new transaction should abort the objects that haven't recieved any transaction messages. in a zope setting this is done automatically, however standalone users should be aware of this. i've posted a modified TM.py to my zope.org member page that contains fixes/workarounds for problems 1 and 2. http://www.zope.org/Members/k_vertigo/ShortStories/Transaction/ in addition the unittests i've been using are posted there as well. i'll commit these changes to TM.py latter today, but have posted the above to zope.org for those who don't want to immediately upgrade. actual fixes for problems 2 and 3 i'll leave to ZC. if you're using a rdbms with zope, i would recommend installing the modified TM.py in replace of the exiting TM.py at lib/python/Shared/DC/ZRDB/TM.py. i would appreciate any feedback from rdbms users who were previously experiencing problems. if this does not solve your problem, and you believe its the fault of the transaction system, please email me. i don't use an rdbms with zope, but i'm happy to further investigate. cheers kapil thangavelu

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Unauthorized users can writelock helpfiles in /Control_Panel/Products
by Ivo van der Wijk 11 Mar '02

11 Mar '02

Hi, I'm sorry to repost my question here, but noone seems to be able to give me any information on the standard Zope mailinlist. I still do, however, find the problem described below annoying, and it could be even considered a security bug (somewhat), or at least a Help page DOS :) -- Hi all, We run Freezope.org, a site where people can get their own folder with Manager/Owner access. Of course, users should not be able to mess up things outside their own folder. However, they can. The problem seems to be with the helpfiles included with the installed products. For some reason, these are sometimes/always changed (as in: writable, modified) when accessed. This often gives us (harmless?) log entries such as: 2002-03-06T03:48:56 INFO(0) Z2 CONFLICT Competing writes at, /HelpSys/menu Traceback (innermost last): File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/Publish.py, line 171, in publish File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: menu) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/Publish.py, line 112, in call_object (Object: menu) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/Shared/DC/Scripts/Bindings.py, line 324, in __call__ (Object: menu) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/Shared/DC/Scripts/Bindings.py, line 354, in _bindAndExec (Object: menu) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/App/special_dtml.py, line 244, in _exec (Object: menu) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/TreeDisplay/TreeTag.py, line 159, in render (Object: a tree tag) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/TreeDisplay/TreeTag.py, line 269, in tpRender (Object: HelpSys) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/TreeDisplay/TreeTag.py, line 523, in tpRenderTABLE (Object: HelpSys) (Info: (['Tm9uZQ==', []], {'childless_decoration': '', 'id': 'tpId', 'branches': 'tpValues', 'url': 'tpURL'}, (['Tm9uZQ==', []],), (['Tm9uZQ==', []],))) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/TreeDisplay/TreeTag.py, line 323, in tpRenderTABLE File /usr/local/zope/Zope-2.4.4b1-src/lib/python/HelpSys/HelpSys.py, line 228, in tpValues File /usr/local/zope/Zope-2.4.4b1-src/lib/python/HelpSys/HelpSys.py, line 331, in tpValues (Object: Help) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZODB/Connection.py, line 535, in setstate ConflictError: ("'\\x00\\x00\\x00\\x00\\x00\\x0f{\\xee'", '<extension class HelpSys.HelpTopic.STXTopic at 85934e8>') --- end of trace --- However, if one of the freezope users creates a version, starts working in this version, and then consults any of the help pages for the installed products, this page will be write-locked, and unaccessible for all other users. When accessing the helppages, the following error appears: Zope Error Zope has encountered an error while publishing this resource. Error Type: VersionLockError Error Value: ("'\\x00\\x00\\x00\\x00\\x00\\x10&r'", '/ZopeHosting/freezope/ivotest.freezope.org/myversion') Troubleshooting Suggestions * The URL may be incorrect. * The parameters passed to this resource may be incorrect. * A resource that this resource relies on may be encountering an error. For more detailed information about the error, please refer to the HTML source for this page. If the error persists please contact the site maintainer. Thank you for your patience. Traceback (innermost last): File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/Publish.py, line 223, in publish_module File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/Publish.py, line 187, in publish File /usr/local/zope/Zope-2.4.4b1-src/lib/python/Zope/__init__.py, line 226, in zpublisher_exception_hook (Object: Config.stx) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZPublisher/Publish.py, line 175, in publish File /usr/local/zope/Zope-2.4.4b1-src/lib/python/Zope/__init__.py, line 240, in commit File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZODB/Transaction.py, line 302, in commit File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZODB/Connection.py, line 420, in commit (Info: (('HelpSys.HelpTopic', 'STXTopic'), '\x00\x00\x00\x00\x00\x10&r', '')) File /usr/local/zope/Zope-2.4.4b1-src/lib/python/ZODB/FileStorage.py, line 658, in store (Object: /usr/local/zope/zopesites/freezope/var/Data.fs) VersionLockError: (see above) --- end of trace --- Could this be considered a bug? Why is this happening at all? With regards, Ivo -- Drs. I.R. van der Wijk -=- Brouwersgracht 132 Amaze Internet Services V.O.F. 1013 HA Amsterdam, NL -=- Tel: +31-20-4688336 Linux/Web/Zope/SQL/MMBase Fax: +31-20-4688337 Network Solutions Web: http://www.amaze.nl/ Consultancy Email: ivo(a)amaze.nl -=-

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Re: [Zope-dev] Usage of try: .. except: .. in zope
by Ivo van der Wijk 11 Mar '02

11 Mar '02

On Sun, Mar 10, 2002 at 05:40:58PM -0500, Craeg K. Strong wrote: > Sorry, I am not answering your question.... > > but I was curious about your product. Have you thought about > restricting Folder contents based on type? That could be extremely > interesting. > It is also something that is on the list to be potentially incorporated > into Zope 2.6 > I definately have, that is, I'm considering filtering allowed metatypes. It won't be in my first release however. Ivo -- Drs. I.R. van der Wijk -=- Brouwersgracht 132 Amaze Internet Services V.O.F. 1013 HA Amsterdam, NL -=- Tel: +31-20-4688336 Linux/Web/Zope/SQL/MMBase Fax: +31-20-4688337 Network Solutions Web: http://www.amaze.nl/ Consultancy Email: ivo(a)amaze.nl -=-

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The future of ZPatterns and LoginManager
by Johan Carlsson [Torped] 11 Mar '02

11 Mar '02

Hi everybody, (I did ask this question to the ZPatterns list, but without any answer. So I hope one better luck here.) I finally got the opportunity to use ZPatterns in a project and am quite please with the result (after the mandatory wrestling :) Anyway, I would like to use both ZPatterns again, as well as LoginManager, but I feel somewhat of a doubt what they will be around in the future and in Zope 3. So, are they? Or what I really want to know, is it safe to base my applications on ZP and/or LM or is it something I'm going to regret? Best Regards, Johan Carlsson torped strategi och kommunikation ab johan carlsson johanc(a)torped.se birkagatan 9 113 36 stockholm västmannagatan 67 http://www.torped.se http://easypublisher.torped.se

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ZODB thread safety issue.
by Romain Slootmaekers 11 Mar '02

11 Mar '02

Yo, I read on the doc's : """ A key feature of Zope 2 (ZODB 3) is that (a copy of) a persistent object is never accessed by more than one thread (unless the programmer goes way out of thier way). Each thread uses it's own database connection(s). Each connection has it's own copies of persistent objects. This feature provides a major simplification for application developers. """ This explains the problems we have with our system: we have a multithreaded system where each thread iteratese over a set of objects in the ZODB, and sees of something needs to be done... if so the thread does it. Now since each thread gets its own version of the object. our actions occur multiple times... This is not the desired behaviour. Is there a way we can share the access to the objects, or do we have to create a global lock ? And if we have to create a global lock, what's the desired/standard approach in doing so. TIA, Sloot.

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