June 2000 - Zope-Dev

adding attributes to a python product
by Steve Alexander 29 Jun '00

29 Jun '00

Hi folks, I have a Python Product that I'm developing. During the course of development, I want to add a new attribute. All new instances get this attribute, as it is defined with a default value in the constructor. In addition, all instances that get edited via the web get the attribute, as the edit-processing method is defined to have a default value for this attribute. Is there any way of interacting with the ZODB persistence machinery to add the default attribute to all instances as they are brought out of persistent storage -- so that I can just restart Zope, and have all of my instances updated as I use them ? I can't find the right method or whatever in the ZODB on-line docs, or in the source. Thanks for any help. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Re: [Zope-dev] Searching a relational database
by Richard Taylor 29 Jun '00

29 Jun '00

James Henstridge <james(a)quoll.daa.com.au> writes: > On Sat, 24 Jun 2000, Thomas Weholt wrote: > > > Hi, > > > > How can I search a relational database thru Zope? ( I`m using PostgreSQL > > 7.0.2 on Linux ). I have a DVD/VHS-organizing project that would be > > pretty useless if people couldn`t search for movies by entering just > > parts of the title. > > > > Ex. typing alien should show "Alien" and "Alien 3". > > If you just want to do a single search term, you could easily set up an > SQL method that read something like: > select * from table where title like '%<dtml-sqlvar search>%' > > (I hope that syntax works with MS SQL server). It is probably possible to > get zope to escape special characters in the string for you as well. > I use the regexp search option in Postgresql (~*) to do complex searches. Unfortunately this means that your users will have to write regular expressions. If anyone is interested in writing a booleans search syntax to regexp converter I would be very interested. > > > > Can ZCatalog be used for this? If I have a SQL-statement that returns > > all rows in a database, can ZCatalog index this? > > This would negate the benefits of having an SQL database (eg. indexing, > etc). Just write an sql method that does the search. > > > > > What I`m looking for is similar to full-text searching on MS SQL 7.0 > > etc. > > > > Tips, hints or pointers?? > > > > Thomas > > > > James. > Richard

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RE: [Zope-dev] adding attributes to a python product
by Brian Lloyd 29 Jun '00

29 Jun '00

> I have a Python Product that I'm developing. During the course of > development, I want to add a new attribute. All new instances get this > attribute, as it is defined with a default value in the constructor. > > In addition, all instances that get edited via the web get the > attribute, as the edit-processing method is defined to have a default > value for this attribute. > > Is there any way of interacting with the ZODB persistence machinery to > add the default attribute to all instances as they are brought out of > persistent storage -- so that I can just restart Zope, and have all of > my instances updated as I use them ? > > I can't find the right method or whatever in the ZODB on-line docs, or > in the source. Steve, The "best way" to do this is to define the new attribute (with its default value) as a class attribute. That way when you ask for the attribute on old instances you'll get the default value found in the class. If you change the attribute (through the web or whatever), the changed attribute will be saved *in the instance*. That way you don't even have to bother setting a default in the constructor (though it won't really hurt anything to do so). For example: # old class class Spam: """A spam object""" def cook(self): return 'cooked!' # new class - we want to add a 'color' attribute that defaults # to 'pink' and to be able to change the color, but we need old # instances to support this too. class Spam: """A spam object""" def cook(self): return 'cooked!' # class attribute - doing a getattr on 'color' will find # this for old instances. color='pink' def setColor(self, color='green'): # if this is called, the color attr will be saved in the # *instance*. The class default will not change. self.color=color Note that there is one caveat to this approach - if the attr that you want a default for is a _mutable_ Python object (like a dict or list), then you have to be careful not to modify the class attribute directly. In those cases you need to do a little more work: class Spam: """A spam object""" # A dict of spam flavors. flavors={} def addFlavor(self, name, desc): # We have to be careful here. We can't just say # 'self.flavors[name]=desc', because if we are an old # instance then self.flavors will give us the 'flavors' # *class attribute*. We don't want to mutate that, what # we really want to do is create flavors as an instance # attribute if we are getting the default. # set dict to either the 'flavors' from the _instance_ or # a fresh new dictionary. dict=self.__dict__.get('flavors', {}) # add the entry dict[name]=desc # this is important - the Zope persistence machinery can't # automatically know about changes to mutable builtin Python # types like dictionaries, so we have do a setattr on self # to make sure the changes to the dictionary are saved! self.flavors=dict Hope this helps! Brian Lloyd brian(a)digicool.com Software Engineer 540.371.6909 Digital Creations http://www.digicool.com

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Using Java-Script with DTML
by Thomas Weholt 29 Jun '00

29 Jun '00

Hi I`m trying to send a parameter to a java-script function and then use that parameter in the java-script function to look up a record-set in a database with a dtml-method. With no luck so far. Ex. <script language="javascript1.2> function ShowStuff(params){ var text = "<dtml-in expr="sqlMethod(some_id=params>"  alert (text); } </script>  <a href=".." onClick="ShowStuff(<dtml-var some_id>);">...</a>  The link sends an id to the java-script-method. A SQL method takes that id as argument and returns a recordset. Or, that`s what I want to happen. How can I get the sqlMethod to take the passed argument and return some data?? I get the thing to work by using static content, like <dtml-in expr="sqlMethod(some_id='1')"> But I need to pass the argument from somewhere else in the document. Oh, this was one big mess. Hope it makes some sense. Thomas

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RE: [Zope-dev] Comments on Zopes performance-article??
by Chris McDonough 29 Jun '00

29 Jun '00

Zope will always fare badly in comparison to web servers that dont serve dynamic content. Zope's delivery will probably never be as fast as serving up static pages from the filesystem ala Apache or AOLServer. This is one of the reasons for ZEO. One of the other things in the wings that's being talked about on some Wiki somewhere is to build better caching in. > -----Original Message----- > From: Thomas Weholt [mailto:Thomas@cintra.no] > Sent: Thursday, June 29, 2000 6:06 AM > To: 'Zope-Dev(a)zope.org' > Subject: [Zope-dev] Comments on Zopes performance-article?? > > > > http://weblogs.userland.com/qube/2000/06/26 > > Just found this article were Zope scores really bad, - compared to the > competition that is. > Any comments? How can Zope improve performance in the future? > > I know Zope has alot of other good qualities, at least > compared to Apache, > but performance tends to be the thing that tips the scale > when people chose > platform, so how will this affect Zope? > > Thomas > > _______________________________________________ > 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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Comments on Zopes performance-article??
by Thomas Weholt 29 Jun '00

29 Jun '00

http://weblogs.userland.com/qube/2000/06/26 Just found this article were Zope scores really bad, - compared to the competition that is. Any comments? How can Zope improve performance in the future? I know Zope has alot of other good qualities, at least compared to Apache, but performance tends to be the thing that tips the scale when people chose platform, so how will this affect Zope? Thomas

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Re: [Zope-dev] Calendar tag 0.9.6 breaks with 2.2.0b3??
by Dieter Maurer 29 Jun '00

29 Jun '00

Dr. Ross Lazarus writes: > Trying the new 2.2.0b3 zope. > One zclass using ty's calendar tag now breaks with an error message I > just cannot figure out - > > Error Type: TypeError > Error Value: unexpected keyword argument: linkDate > > File /usr/local/zope/zope22b3/lib/python/DocumentTemplate/DT_Util.py, > line 262, in namespace > TypeError: (see above) > > I added __allow_access_to_unprotected_subobjects__=1 to the CalendarTag > class just in case. > > The offending line in CalendarTag.py is > > ns = namespace(self, > date = date, > mode = self.mode, > firstday = firstday, > setCalendar = self.setCalendar_, > getCalendar = self.getCalendar_, > linkDate = self.linkDate_ > )[0] > > > namespace in DT_Util seems harmless enough - > > def namespace(self, **kw): > """Create a tuple consisting of a single instance whos attributes are > provided as keyword arguments.""" > return apply(self, (), kw) The "self", more precisely, its "__call__" gets the keyword "linkDate" which it does not (no longer) likes to have. Dieter

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ZTopic displays wrong tabs
by Steve Alexander 28 Jun '00

28 Jun '00

Hi folks, I'm using ZTopic. One thing I've noticed about the management interface is that, although an appropriate tab is highlighted when you click that tab, if you go to a subsequent screen, often "contents" will erroneously become the highlighted tab. This is causing problems as I explain to non-technical folk how to use ZTopics. I say "select the contents tab", and they say "but the contents tab **is** selected!". I have a fix for this, but the real problem is in the logic of lib/python/App/manage_tabs.dtml: <dtml-call "REQUEST.set('a_', 0)"> <dtml-in manage_options mapping> <dtml-if expr="URL[-(_.len(action)):]==action or URL[-17:]=='/manage_workspace' and _['sequence-start']"> <dtml-call "REQUEST.set('a_', _['sequence-index'])"> </dtml-if> </dtml-in> Here, the variable 'a_' represents the "active" tab. If the last part of the URL matches one of the manage_options of the current object, then that tab will be the highlighted one. Otherwise, the first tab will be highlighted. It should ideally be possible to tell manage_tabs what tab should be highlighted, imperatively, when required. However, in the absence of such a mechanism, I have changed the DTML files in ZTopic like this: The form searchEdit.dtml is really part of the "Search Criteria" logic, so I want that tab highlighted. That tab's action attribute is called "editForm". Therefore, in the file searchEdit.dtml, I replace this: <BODY BGCOLOR="#FFFFFF" LINK="#000099" VLINK="#555555">  <p>Edit catalog search criterion number <dtml-var "index+1"> on Catalog <strong><dtml-var catalog_id></strong>.</p> With this: <BODY BGCOLOR="#FFFFFF" LINK="#000099" VLINK="#555555"> <dtml-with "_.namespace(URL='editForm')"> <dtml-var manage_tabs> </dtml-with> <p>Edit catalog search criterion number <dtml-var "index+1"> on Catalog <strong><dtml-var catalog_id></strong>.</p> (I modernised the  to <dtml-var ...> along the way.) To get the full effect, you'd need to do a similar trick with the other dtml files in ZTopic. Any takers for a full patch? Or, is there a better way of doing this that I don't know about? -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Prototyped folders?
by Steve Alexander 28 Jun '00

28 Jun '00

Hi Hamish, I've answered your message in Zope-Dev, as this seems to be more of a developers' question. Hamish wrote: > If a folder doesn't itself contain a required object or method, I'd > like to have another folder looked in instead. The fall-back folder > won't necessarily (and often can't) be higher in the hierarchy, so > acquisition doesn't seem to be a solution. This looks like a job for a Python class that uses the new Traversal interface. http://www.zope.org/Members/michel/Projects/Interfaces/Traversal Your requirements sound very much like those for Shane Hathaway's Transparent Folders product, except that instead of briefly diverting acquisition into the transparent folder, you want to briefly divert acquisition into some other arbitrary folder. Last I heard, Shane was going to revitalize Transparent Folders when the various interfaces it uses are finalized for Zope 2.2. I suggest that after Shane has re-released his product, you make a product based on Transparent Folders that works in this slightly different way. Or, if it is appropriate, consider your changes an enhancement to Transparent Folders, and offer it as a patch. If you don't have sufficient python-hacking-zope-hacking-Zen to do it yourself, I think I might have a go (and hopefully learn some Zope internals Zen in the process). Transparent Folders were here: http://www.zope.org/Members/hathawsh/ - but the link to them is broken -- I guess because the product was withdrawn as there was a problem with it under Zope 2.1.6. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Confera fix
by Jon Franz 28 Jun '00

28 Jun '00

Attached is a slightly modified Confera.py that does not require the ts_regex python package (something I do not have on my system and cant seem to find - and yet something Confera will choke on during message posting if it doesn't exist) I've put the moded Confera.py up in my member folder at: http://www.zope.org/Members/Coventry/Confera_Fix Anyone who has problems utilizing Confera due to no ts_regex may find this useful. Does anyone know where to find ts_regex by itself? If its not readily available (I cannot find it) I'd suggest making a minor point release of Confera that does not need it. <<Confera.py>>

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