- Zope-Dev - Zope lists

Zope Job in Charlotte, NC
by Jeff K. Hoffman 14 Feb '00

14 Feb '00

Going Virtual, L.L.C., an internet company serving the non-profit industry, is immediately seeking a Python/Zope developer in the greater Charlotte area and the surrounding Carolinas to add to our small, tightly knit development team. This position requires 2-3 years of programming experience, in general; 1 year of experience with Python; and 6 months of experience with Zope. Must have good working knowledge of relational databases. Candidates with a strong background in Object Oriented development will be preferred. Salary commensurate with skills and experience. If you live outside the local area and wish to relocate, please advise accordingly. Applicants must be authorized to work in the USA. For further information please e-mail your most current resume to mailto:jeff@goingv. Plain text preferred, StarWriter, Word, and RTF accepted. --- Jeff K. Hoffman 704.849.0731 x108 Chief Technology Officer mailto:jeff@goingv.com Going Virtual, L.L.C. http://www.goingv.com/

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Announce: Persistent list class
by Andrew Wilcox 14 Feb '00

14 Feb '00

Here's a small but useful utility class that implements persistent lists. It recognizes when it has been modified, and triggers the ZODB persistence mechanism. I also threw in a PersistentDict class that implements persistent dictionaries. This is very similar to the PersistentMapping that comes with Zope, but is a little more straightforward. It doesn't restrict keys to be strings, and doesn't hide keys that begin with an underline. Code is available at http://www.zope.org/Members/AndrewWilcox/PersistentListDict As an example, here's a class that uses a regular Python list. Because the ZODB doesn't know when the list has been modified automatically, the programmer needs to trigger persistence by setting one of the object's attributes. class Myclass (Persistent): def __init__(self): self.l = [1, 2, 3, 4, 5, 6] def act(self): l = self.l l[2:4] = [33, 37, 39, 41, 44] self.l = l By using a PersistentList, the ZODB will know when the list has been changed. class Myclass (Persistent): def __init__(self): self.l = PersistentList([1, 2, 3, 4, 5, 6]) def act(self): self.l[2:4] = [33, 37, 39, 41, 44] I am experiencing a bug in Zope 2.1.4 where the comparision method, __cmp__, is not getting called consistently in Persistent subclasses. Don't know what that it about. If you need to compare persistent lists, use list() to get you a regular list and compare on that.

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RE: [Zope-dev] Computed fields in ZCatalog
by Martijn Pieters 14 Feb '00

14 Feb '00

From: Kevin Dangoor [mailto:kid@kendermedia.com] > > Looking at the ZCatalog code, if an index or metadata > field is callable > for a particular object, then that function will be called. > However, it > isn't called with *any* parameters. Is there any way to make > that metadata > value based upon other values in the object? > > For example, if I wanted to create a method that would return > Property1+Property2 and have that value show up in the > Catalog, can that be > done? Only with methods that don't need any arguments, like an External Method. DTML Methods required arguments, so they will not do. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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Enabling cut/copy/paste/rename in ObjectManagers
by Adrian Hungate 13 Feb '00

13 Feb '00

I have re-written my ZStyleSheet product in python (I was having problems that I could not solve easily with DTML Methods) but I have hit another problem. I have 4 basic object classes, two of which are ObjectManagers, and I had (naively) expected them to immediately support cut/copy/paste/rename, but it would seem that my objects don't support these functions, and I can't work out why. Could someone tell me what an object needs to support these functions, and do the changes need to be to the parent or child objects? Haqa...

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RE: [Zope-dev] tracking user usage
by Martijn Pieters 13 Feb '00

13 Feb '00

From: ethan mindlace fremen [mailto:mindlace@imeme.net] > > A long time ago in a galaxy far, far, away, a Zopista said > that I could > easily track user's space utilization. Could someone point me to the > hooks or wherever else I need to go to implement something like this? > > Specifically, I just need to track how big the stuff in a SiteAccess > folder gets. > > (of course, i have to cross-reference that with disk quotas, > but that's > another kettle of fish) > I think this is the email you are referring to: http://lists.zope.org/pipermail/zope-dev/1999-December/002537.html It contains just about all _I_ know about the accounting hooks. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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RE: [Zope-dev] Database connections
by Martijn Pieters 13 Feb '00

13 Feb '00

From: Stephan Richter [mailto:srichter@cbu.edu] > My client went live with a site today and we are having huge problems > with the DB connections. Every one out of five times the request will > time out. We are heavily using DB tables for our data storage. (We are > using PostGres.) > > My client has read that other people experienced the same issue, since > only 7 DB connections are allowed at a given time. She read > that you can > hack the python code somewhere. I am sure you guys know how > to do this. > If you could send me a set of instructions of how to fix it, > that would > be great. As the ZPostgreSQLDA is not thread safe, it uses only one DB connection for all threads. It is a so-called level 2 DA. For an explanation, see: http://www.zope.org/Members/petrilli/DARoadmap I thus doubt that your problem is related to the 7 ZODB connection limit. I you don't specify how many threads Zope should use (with z2.py), you will never run into this limit. I suggest you first try and pinpoint the problem. The following HowTos might help: http://www.zope.org/Members/mcdonc/HowTos/DEBUG-LOG http://www.zope.org/Members/klm/debuggingzope http://www.zope.org/Documentation/Misc/DEBUGGING.txt Also, have a look at /Control_Panel/manage_debug. I have a feeling it might be related to the ZPostgreSQLDA, but that is only a hunch, nothing concrete. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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tree tag interfer with other
by Sin Hang Kin 13 Feb '00

13 Feb '00

I just found out that if you grow more than one tree, if you click on one, all will expand or collesp. HA!

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RE: [Zope-dev] Expressions like <dtml-var this url> bail out cont rary to intuition -- proposed fix enclosed
by Martijn Pieters 13 Feb '00

13 Feb '00

From: Jarkko Kniivilä [mailto:jarkko.kniivila@ambientfactor.fi] > > While upgrading a Zope 2.1.0 beta installation recently to 2.1.3, I > discovered that a recent change made to 'DT_Var.py' rendered DTML > expressions like <dtml-var this url> and &dtml.url-this; > inoperative. I had > been relying on them for a default action url on my forms (in > DTML methods). > Especially the entity reference syntax is quite a nice > abbreviation for the > more explicit <dtml-var "this().absolute_url()"> which still > continues to > work. > > The enclosed fix simply acknowledges that 'this' isn't a ZODB > namespace > object but a method encapsulating python 'self' and thus > always needs to be > invoked. I'm not quite on the top of things why the previous > behavior was > changed in the first place (Jim? Anyone?). > > I'll file this to the Collector if there's no objection by > you. Copyright to > the patch is hereby transfered to Digital Creations to be used freely. Breaking access to this().abosulte_url() in the above way was probably not intentional. Yes, please put it in the Collector, as it may get lost otherwise. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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RE: [Zope-dev] Scheduler product, anyone?
by Martijn Pieters 13 Feb '00

13 Feb '00

From: Loren Stafford [mailto:lstafford@icompression.com] > 1. Starting the Dispatcher on Zope start-up. > The only place I can think to put this kind of initialization > logic is in > __init__.py of the product. > That code would have to look for any already-created instance > and (if found) > run it's Dispatcher method in a separate thread. Is there any > way to do > this? I have a feeling I'm confused on this point. I seems odd for > __init__.py to look for instances. > > 2. Does it make sense to provide for more than one instance of the > scheduler? I can't think of a reason. But then you couldn't > prevent someone > from creating as many as they want, could you? > > 3. Managing separate threads. > Will Zope's persistence and transaction mechanism provide all > the mutual > exclusion I need on the schedule queue? ...or do I need some > kind of lock? As a little follow-up: It was I who had already started a ZScheduler project, and worked out how to do the architecture, and wrote some initial code. Due to a new job here at DC, I ran out of time for the project completely. I have now however, transferred my ideas to Loren in a private email conversation, including all code I had on the subject. Code included a ZCatalog based scheduler object automatically being created in the root, and 'write-protecting' it (like the standard_html_header, _footer, and _error objects). Also, registering of Event objects was in place. I hereby have handed over my project to Loren to do with it as he sees fit. =) -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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RE: [Zope-dev] HTTP HEADER
by Martijn Pieters 13 Feb '00

13 Feb '00

From: Sin Hang Kin [mailto:iekentsin@infoez.com.mo] > > I am trying to make the following with XMLDocument: > > Extract a branch of the xml-tree and adding a xml header with > apropriate xsl > which the browser which can recogniz xml can use the xsl to render the > branch of the tree. > > I have made a method which have : > > <?xml version="1.0"?> > <dtml-var "toXML()"> > > however, Zope send > > <html><head> > <base href="http://..... > > before the method's output. > > Can I ask Zope not to send this? Yes, by setting the content-type to text/xml, or anything that is not text/html. Add the following line to your code somewhere: <dtml-call "RESPONSE.setHeader('content-type', 'text/xml')"> -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

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