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[ZGotW] Issue #1 Entry
by Zope Guru of the Week 21 Jan '00

21 Jan '00

=================================================================== Issue #1 -- DTML Subroutines =================================================================== Status: Open Zen Level: Novice (1/8) Keywords: DTML Submitted by: Tres Seaver tseaver(a)palladion.com ------------------------------------------------------------------- Suppose you have been happily hacking away at your Zope site, and discover that you are reusing a chunk of DTML over and over::  <dtml-in "objectValues( 'FooType' )"> <tr> <td> <a href="&dtml-id;"><dtml-var id></a> </td>  </tr> </dtml-in> Now, you decide to "refactor" the site to follow the "Once and Only Once":http://c2.com/cgi/wiki?OnceAndOnlyOnce dictum of "Extreme Programming":http://www.extremeprogramming.org : i.e., you'd like to make this snippet a reusable "subroutine," so that you could make changes to it in just one place. How do you move this code out into a DTML Method and then replace all the cloned copies with calls to that method? ------------------------------------------------------------------- Entry from: ross lazarus rossl(a)med.usyd.edu.au ------------------------------------------------------------------- making a dtml method showfoo and calling it as <dtml-call "displayfootypes(_.None,_)"> will work. I've even done it once or twice. A long time ago. In my view, the most efficient and effective way to deal with this common situation is to write a python script and make it an external method. Called in the same way. My personal experience is that writing anything beyond mildly complex requires truly brain destroying dtml - the time to design, write, test, debug and so on is much longer with dtml once you go over a certain level of complexity compared with coding and testing in Python - which is much quicker for me. Remember, dtml was not designed for heavy duty programming. Python was. I've also informally benchmarked python external methods to be 5 to 10 times faster on the first call (yes, there's overhead in dtml) for anything longer than a few lines - although zope caching means second and subsequent cached calls are generally indistinguishable. Downside is that you have to move your external methods with the application. No big deal as long as you remember (!). You lose the total through the web thing too - editing python scripts means some additional software and futzing. My 2c worth. Use dtml only for extremely simple stuff. When the going gets tough, make it easy on yourself and use external methods... -------------------------------------------------------------------

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Re: Zope digest, Vol 1 #593 - 58 msgs
by Tres Seaver 21 Jan '00

21 Jan '00

> From: "Shaw, Mark" <Mark.Shaw(a)cadus.com> > To: zope(a)zope.org > Subject: [Zope] Upgrading Zope - Effect on Z Classes > Date: Thu, 20 Jan 2000 10:39:30 -0500 > charset="iso-8859-1" > > Hello All, > > I'm trying to upgrade a Zope 2.0.1 site to 2.1.2. I used > http://www.zope.org/Members/mcdonc/HowTos/zopeinstall/ZOPE-INSTALL-HOWTO > <http://www.zope.org/Members/mcdonc/HowTos/zopeinstall/ZOPE-INSTALL-HOWTO> > as a reference guide. Everything seems to have worked fine except for a Z > class that I had previously created. I created a new product as described > in http://www.zope.org/Members/lstaffor/zProperties > <http://www.zope.org/Members/lstaffor/zProperties> After performing the > upgrade, the product is no longer functional. > > As an alternate route, I tried exporting the product to a .zexp file. That > worked fine, but I was then unable to import the file into the new Zope > instance. > > Is there an upgrade path for Z Classes that I am as yet unaware of? I still > consider myself a newbie. Any ideas? Thanks in advance for any help > provided. > > -Mark Hmm, I move ZClass-based products back and forth between 2.0.1 and 2.1.2 all the time. A couple of possible gotchas: * When you export the product DO select it in the Products list and push the "Export" button, but DON'T select the "As XML" checkbox (Zope can't reimport the file as XML). * If your ZClasses have ExternalMethods, then you need to move them as well. On 2.0.1, these have to be in the $INSTANCE_HOME/Extensions directory; in 2.1.2, you can create a directory for your Product under $INSTANCE_HOME/lib/Python/Products, and then put the Python file into the Extensions subdirectory under it -- you can then refer to it as "FooProduct.SomeModule" in the ExternalMethods. * If your ZClass inherits from another non-standard ZClass, you need to install the base class first. Hope this helps! Tres. -- ========================================================= Tres Seaver tseaver(a)palladion.com 713-523-6582 Palladion Software http://www.palladion.com

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Re: [Zope] dtml-sendmail gotcha
by Tres Seaver 20 Jan '00

20 Jan '00

Donald G Porter <dgp(a)cam.nist.gov> wrote: > > Here's a challenge. What's wrong with the following DTML snippet? > > <dtml-sendmail mailhost="MailHost"> > To: <dtml-var email> > From: Example.Net <WebStaff(a)example.net> > Subject: Joining Example.Net > > To complete your registration with Example.Net (blah blah...) > > </dtml-sendmail> > > On my Zope site I had a similar DTML snippet, and it refused to > send the mail message, but it also gave no error message that I > could see, so debugging it took a ***long*** time. Do you see > the problem? > > Here's what worked for me: > > <dtml-sendmail mailhost="MailHost"> > To: <dtml-var email> > From: "Example.Net" <WebStaff(a)example.net> > Subject: Joining Example.Net > > To complete your registration with Example.Net ... > > </dtml-sendmail> > > Those double quotes can make a world of difference. I'm posting this > to the Zope mailing list in the hope that it will keep others out > of this blind alley which cost me so much time and frustration. Good > thing my site is for fun and not for profit! I have another fun one for you. Imagine a ZClass which sends e-mail automagically as its state changes, and embeds attributes like its id and title in the mail. The DTML method which sends the mail looks like:: <dtml-sendmail mailhost=MailHost> From: Zope Guru of the Week <ZGotW(a)palladion.com> To: <dtml-var "_.string.join( toAddressList, ',' )"> Cc: <dtml-var "_.string.join( ccAddressList, ',' )"> Subject: [ZGotW] Issue #<dtml-var id> (<dtml-var status>) Date: <dtml-var ZopeTime>  <dtml-var issue_txt> </dtml-sendmail> </dtml-let> The sendmail tag seems to push the MailHost onto the top of the acquisition stack, so that id, title, and absolute_url now render via the folder containing the MailHost, rather than the ZClass instance whose method is being called! The fix is to externalize the values before entering the sendmail tag:: <dtml-let issueID=id issueURL=absolute_url issueTitle=title> <dtml-sendmail mailhost=MailHost> From: Zope Guru of the Week <ZGotW(a)palladion.com> To: <dtml-var "_.string.join( toAddressList, ',' )"> Cc: <dtml-var "_.string.join( ccAddressList, ',' )"> Subject: [ZGotW] Issue #<dtml-var issueID> (<dtml-var status>) Date: <dtml-var ZopeTime> <dtml-var "issue_txt( _.None, _ , issueTitle=issueTitle , issueURL=issueURL )"> </dtml-sendmail> </dtml-let> Ugh! -- ========================================================= Tres Seaver tseaver(a)palladion.com 713-523-6582 Palladion Software http://www.palladion.com

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[Announce] Zope Guru of the Week Debut
by Tres Seaver 20 Jan '00

20 Jan '00

*Apologies for publishing the first issue in advance of this explanation: my "trigger finger" bounced on the mouse.!* What is Zope GotW? Zope GotW is a "contest," run on the Zope(a)zope.org mailing list, where the prize is undying glory. ZGotW is designed to highlight some of the non-obvious corners of Zope usage -- the Zope Zen of the True Guru. The idea is drawn from the popular C++ GotW run by Herb Sutter on comp.lang.c++. How does it work? 1. Members of the Zope community submit suggested problems for future issues using the "Submit an Issue Topic" link in the navigation bar. 2. The Editor selects a topic for a new issue, either from among the submissions or on his own, and identifies a Reviewer for the topic, soliciting agreement from the Reviewer. 3. The Editor pretties up the issue and publishes it, which causes it to appear in the "Current Issues" secion of the site's navigation bar, and sends e-mail to the Zope list containing the question and a link to the issue's page. 4. Zope community members respond to the issue, posting their solutions via the issue's page. These solutions are mailed to the Reviewer, and optionally, to the Zope list for discussion. 5. At the end of the issue's "life" (normally a week), the Reviewer closes the issue to new submissions, summarizes the responses, awards "guru points", and posts a full solution. This solution is then mailed to the Zope list, where it may provoke further discussion. Where is the Code? I have set up a Software Product on my Zope.org homepage: "ZGotW Product":http://www.zope/org/Members/tseaver/ZGotW ToDo's * Add search functionaliy (the Catalog is already there, just needs UI). * Add knob to allow submitter/editor/contestant/reviewer to upload one or more files with their message (the message is already folderish). -- ========================================================= Tres Seaver tseaver(a)palladion.com 713-523-6582 Palladion Software http://www.palladion.com

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RE: [Zope] ZSQL Methods and +
by Chris McDonough 20 Jan '00

20 Jan '00

Matt, I'm in the process right now of establishing use cases for banner ad management products. Many of our customers are asking for this kind of thing. We haven't decided yet whether to build a product, build on the efforts of the community, or to refer our customers to outsourcers or 3rd-party software tools. But I'd be very interested in hearing what your "perfect" banner ad management software would look like. Chris McDonough mailto:chrism@digicool.com Digital Creations http://www.digicool.com Publishers of Zope http://www.zope.org > -----Original Message----- > From: Matt Miller [mailto:matt.miller@thelinuxstore.com] > Sent: Thursday, January 20, 2000 5:24 PM > To: Bill Anderson > Cc: zope(a)zope.org > Subject: Re: [Zope] ZSQL Methods and + > > > Bill Anderson wrote: > > > > Matt Miller wrote: > > > > > > I have just joined this list, so forgive me as I break my > cardinal rule > > > of reaidng a list for a while before posting. > > > > > > I am working on a banner ad rotation system for my Zope > installation. > > > To that end I am using a rather simple algorithm to > determine which ad > > > should be shown: > > > > While not specifically solving your problem, have you looked at the > > Advertsising Banner Folder product? > > Yes, I have. I couldn't find a good way to produce the > reports which my > boss (and presumeably our customers) demand. I need to be > able to count > impresions AND click throughs. > > > I am currently working on modifiying and extending it, but > am running > > into some issues. > > Welcome to my world! > > > > Each time an ad is selected, ads not shown have their > "notshown" count > > > incremented by 2. > > > An ad is selected whenever the number of impressions > remaining PLUS its > > > "notshown" is the largest in the DB. > > > > Hmmm sounds like that number could get quite large. Is this > a method you > > are using for 'weighting' various banners? IOW, give > certain banners a > > higher base notshown count? > > Yes, this is a eighting. I have two considerations in the weighting. > One I don't want to just shuffle thru the banners.. some customers ma > buy twice as many banners as another.. usually they want maximum short > term impact, so I don't want to stretch their 10 million impressions > over 100 million hits (in the case of ten banner sin the > system).. but I > don't want to wait for the numbers to equalize, either. This method > seems like a 'fair' way to get heavy buyers heavy rotation up front. > > I forgot an important piece of this. When a banner IS shown, its > notshown gets reset to 0. So the idea is if you have more > impressions, > we show you more often.. but not to the exclusion of the other ads in > the system... eventually they will get 'niced' up to the top, even if > they only have one impression left and another has 10 million. > > I know I will need a more sophisticated algorithm in the > future, but for > today, I just need my addition! > > > > > This is part of where I am working on in a banner product. > > Cool, maybe I should look more carefully at the banner > product. I have > written one similar to the one I am trying to recreate here, so it > seemed this would be quicker... but perhaps not if I can't > add in my SQL > selects. > > > -- > Matt Miller > matt.miller(a)thelinuxstore.com > > _______________________________________________ > Zope maillist - Zope(a)zope.org > http://lists.zope.org/mailman/listinfo/zope > ** No cross posts or HTML encoding! ** > (Related lists - > http://lists.zope.org/mailman/listinfo/zope-announce > http://lists.zope.org/mailman/listinfo/zope-dev ) >

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Database loss problems
by Gregor 20 Jan '00

20 Jan '00

Does Zope store changes to the database in memory for an extended period, rather than storing them in the data.fs file? I've been noticing that after a system crash (unrelated to Zope) the database will revert to an earlier state *even if Zope was running for some time after the changes were made*. I must be misunderstanding the way the undo system works. I wasn't aware that the database had to be packed in order to be actually saved to disk. - Gregor http://anime.at/gregordyne Mage, Anime, Gernsback, Eidolon, Miscellany

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BannerFolder banner and aquisition?
by Bill Anderson 20 Jan '00

20 Jan '00

OK, having been a while since I last worked on a non-horrible-kludge banner product, I decided to give BannerFolder a shot. Works quite well. However, it is only fo rbanners where the image is stored locally. Many banners these days are not done this way, rather you get a full href, including an <img src=....> tag. So what I thought I would start with was to add a property called local, and modify Banner's render method to return _jusr_ the hit_URL for non-local banners. Works fine except when it comes time to render the image. Th eimage is always broken. After some digging, I determined that Zope is inserting the bannerfolder's id into the image tag's image tag such that: <img src="<http://link-toimage-on-other-site"> becomes: <img src="hbanner/http://link-toimage-on-other-site"> Now, what I was doing in my banner kludge was to have the same basic setup, and I used a with tag for the banner folder. So, my question is "how do I get Zope to _not_ put the 'hbanner/' into the img src tag?" That aside, anyone know of any good way of implementing a weighting mechanism to work with BannerFolder? So far, I have an idea about creating a list of banners to choose from, banners would have a weight of 1, with the weight being the number of times they appear in the list. Thoughts? (this aspect of the question may be more sutied to the zope-commerce list) Bill -- In flying I have learned that carelessness and overconfidence are usually far more dangerous than deliberately accepted risks. -- Wilbur Wright in a letter to his father, September 1900

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ZSQL Methods and +
by Matt Miller 20 Jan '00

20 Jan '00

I have just joined this list, so forgive me as I break my cardinal rule of reaidng a list for a while before posting. I am working on a banner ad rotation system for my Zope installation. To that end I am using a rather simple algorithm to determine which ad should be shown: Each time an ad is selected, ads not shown have their "notshown" count incremented by 2. An ad is selected whenever the number of impressions remaining PLUS its "notshown" is the largest in the DB. To that end I am trying to use the following query template to return the pointers to the ad to be displayed: select image, alt, id, imprem+notshown as fr from ads where imprem > 0 order by fr DESC LIMIT 1 As I quickly discovered the use of the '+' causes Zope to choke with a "keyError": Error, exceptions.KeyError: unhandled SQL used: select image, alt, id, imprem+notshown as fr from ads where imprem > 0 order by fr desc LIMIT 1 Traceback (innermost last): File /usr/local/www/Zope-2.0.0b5/lib/python/ZPublisher/Publish.py, line 209, in publish_module File /usr/local/www/Zope-2.0.0b5/lib/python/ZPublisher/Publish.py, line 179, in publish File /usr/local/www/Zope-2.0.0b5/lib/python/Zope/__init__.py, line 199, in zpublisher_exception_hook (Object: getad) File /usr/local/www/Zope-2.0.0b5/lib/python/ZPublisher/Publish.py, line 165, in publish File /usr/local/www/Zope-2.0.0b5/lib/python/ZPublisher/mapply.py, line 154, in mapply (Object: manage_test) File /usr/local/www/Zope-2.0.0b5/lib/python/ZPublisher/Publish.py, line 102, in call_object (Object: manage_test) File /usr/local/www/Zope-2.0.0b5/lib/python/Shared/DC/ZRDB/DA.py, line 310, in manage_test (Object: getad) File /usr/local/www/Zope-2.0.0b5/lib/python/Shared/DC/ZRDB/DA.py, line 291, in manage_test (Object: getad) File /usr/local/www/Zope-2.0.0b5/lib/python/Shared/DC/ZRDB/DA.py, line 395, in __call__ (Object: getad) File lib/python/Products/ZMySQLDA/db.py, line 191, in query KeyError: (see above) Is this a known problem? Have I done something incredibly stupid? I am able to use this syntax from the mysql monitor as well as in perl cripts. I have tried various combos of parens and escaping, to no avail. Thanks. -- Matt Miller matt.miller(a)thelinuxstore.com

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RE: [Zope] WebDAV, Zope object locking
by Hung Jung Lu 20 Jan '00

20 Jan '00

>From: Michel Pelletier > > When several people are working on the same site, > > what is the current approach in preventing two > > people modifying the same object? >Lock the object in a version so that the user who is not currently >logged into the version gets an error when they try to modify the >object. Wow! I never played with Zope version feature, partially because I am used to Microsoft's Visual Source Safe and it is a monsterous pain. Zope's version feature is so much simpler and makes so much more sense! I am impressed. I guess I'll have to be more careful with what Microsoft wants to make me believe. :) thanks! Hung Jung ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com

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Editing Properties of ZClasses
by James W. Howe 20 Jan '00

20 Jan '00

I've just created a ZClass which subclasses from Image. I've added a property sheet to allow for an additional attribute called caption. I tweaked the factory/addForm/add methods to let a user specify the caption when they specify an image. Basically the add form is just like you see with an Image add, except there is an additional field for the caption. My ZClass currently has views for things like Edit, Upload, Properties, etc which it mostly inherited from Image. The Properties view displays the property sheet appropriate for my ZClass. What I would like to do, however, is let the user modify the caption property from the Edit screen instead of the Properties screen. I used the code from imageEdit.dtml and made modifications to show the caption value and to let the user change it. However, the caption doesn't show up. I think I understand why (the caption property is in a property sheet which isn't visible to this particular DTMLMethod) but I'm not sure how to fix the problem. Can anyone provide some suggestions? Thanks. James W. Howe mailto:jwh@allencreek.com Allen Creek Software, Inc. pgpkey: http://ic.net/~jwh/pgpkey.html Ann Arbor, MI 48103

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