August 2000 - Zope-Dev

Re: [Zope-dev] ZPatterns bug with patch
by Steve Alexander 28 Aug '00

28 Aug '00

"Phillip J. Eby" wrote: > > At 10:22 AM 8/27/00 +0100, Steve Alexander wrote: > > > >I've fixed this by adding a test to the start of __set_attr__ of > >DataSkins.py: > > > > def __set_attr__(self,name,val,_v_dm_=_v_dm_): > >+ if name=='id' and val==self.__dict__['id']: > >+ return > > dm = self.__dict__[_v_dm_] > > This looks reasonable, and backward-compatible, since __init__ guarantees > the dict will have an id. I'm not thrilled with adding more overhead to > attribute setting, however, so I'll probably do it like this: > > try: > dm = self.__dict__[_v_dm_] > except KeyError: > if name=='id' and val==self.__dict__['id']: return > raise > > Hopefully this should only perform the extra computations when the first > part fails... Are Python classes derived from DataSkin supposed to call DataSkin.__init__ ? Anyway, perhaps this would be a small improvement: try: dm = self.__dict__[_v_dm_] except KeyError: if (name=='id' and self.__dict__.has_key('id') and val==self.__dict__['id']): return raise -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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RE: [Zope-dev] Transaction question
by Chris McDonough 28 Aug '00

28 Aug '00

Using a mutex by way of example, without using anything Zope-specific (the following uses the Python threading module): import threading lock = threading.Lock() myglobal = [] def changeglobal(val): lock.acquire() try: myglobal.append(val) finally: lock.release() > > (I suppose class attributes needs to be protected to be thread-safe? > > Does anybody have an example how to do that?) > > You can use allocate_lock() to accomplish thread safety with class > attributes.

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inheritedAttribute
by Steve Alexander 28 Aug '00

28 Aug '00

In the latest Zope source, I've noticed calls to inheritedAttribute in the Python code. I've found the C source code in ExtensionClass.c, but it doesn't help me understand when I should use it from Python, and why. *reads more source* Ah! About 70 lines further on in ExtensionClass.c: "inheritedAttribute(class,name) -- Get an inherited attribute\n\n" "Get an attribute that would be inherited if the given (extension)\n" "class did not define it. This method is used when overriding\n" "inherited methods. It provides 2 advantages over accessing\n" "\n" "attributes directly through a superclass:\n" "\n" "1. The superclass need not be known,\n" "\n" "2. The superclass may be a Python class. Without this method, it would\n" " be possible to override methods inherited from python classes because\n" " unbound methods gotten from Python classes cannot be called with \n" " extension class instances. \n" Is there some documentation of this on zope.org or dev.zope.org that I've missed? Thanks. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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New method for ZCatalog: recatalog_object
by Steve Alexander 27 Aug '00

27 Aug '00

ZCatalog would be easier to use if it had a recatalog_object method: def recatalog_object(self, obj, uid): """Adds object to the catalog if not already present. Removes old entry first, if already in present.""" self.uncatalog_object(uid) self.catalog_object(obj, uid) This, and a new method in Traverable.py would make cataloging in ZPatterns SkinScript very easy indeed. Add to Traversable.py: getPathAsString__roles__=None # Public def getPathAsString(self): '''Returns the physical path as a string. The returned string will always start with a slash.''' return join(self.getPhysicalPath(), '/') Otherwise, ZCatalog could be altered to accept lists of strings as uid method attributes, and automatically convert them into slash-separated strings. Example SkinScript: WHEN OBJECT ADDED, CHANGED CALL Catalog.recatalog_object(self, self.getPathAsString()) WHEN OBJECT DELETED CALL Catalog.uncatalog_object(self.getPathAsString()) Any comments? -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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keeping state of tree over different documents
by Marcus Schopen 27 Aug '00

27 Aug '00

Hello, I'm trying to do the following: - documents containing a tree navigation are created dynamically using standard_header and footer. - the navigation tree is NOT located in a frame but in a table cell which is reloaded together with the rest of the page each time a link in that navigation is selected - the navigation tree is automatically created by using a dtml-method. The problem that occurs is, that the tree`s open/close state is not correctly maintained over the different documents. A solution to that might be to append the state of the tree after selection of a link to the it's URL as ?tree-s=.... ; that means pass the future state of the tree to the selected page by using URL-Parameters. Any ideas how to do that or any other ideas? Thank you Marcus

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ZPatterns bug with patch
by Steve Alexander 27 Aug '00

27 Aug '00

Zope 2.2.1, ZPatterns 0-4-1snap1 I can't add a Dataskin-derived ZClass beneath a Customizer Folder any more. I think the order of something in the initialization of ZClasses has changed in Zope. It appears that the DataSkin's datamanager isn't being found before __set_attr__ is called for the first time. __set_attr__ is being called with name="id" val="id_of_object" Interestingly, __init__ in DataSkins.py is also being called with the value id. This is because in ZClass.py:createInObjectManager, the id is given to __init__ in the first statement, and set as an attribute in the second. def createInObjectManager(self, id, REQUEST, RESPONSE=None): """ Create Z instance. If called with a RESPONSE, the RESPONSE will be redirected to the management screen of the new instance's parent Folder. Otherwise, the instance will be returned. """ i=mapply(self._zclass_, (), REQUEST) i._setId(id) I've fixed this by adding a test to the start of __set_attr__ of DataSkins.py: def __set_attr__(self,name,val,_v_dm_=_v_dm_): + if name=='id' and val==self.__dict__['id']: + return dm = self.__dict__[_v_dm_] Here's the traceback before I applied the patch: Error Type: KeyError Error Value: _v_dm_ Traceback (innermost last): File lib/python/ZPublisher/Publish.py, line 222, in publish_module File lib/python/ZPublisher/Publish.py, line 187, in publish File lib/python/Zope/__init__.py, line 221, in zpublisher_exception_hook (Object: RoleManager) File lib/python/ZPublisher/Publish.py, line 171, in publish File lib/python/ZPublisher/mapply.py, line 160, in mapply (Object: Drug_add) File lib/python/ZPublisher/Publish.py, line 112, in call_object (Object: Drug_add) File lib/python/OFS/DTMLMethod.py, line 172, in __call__ (Object: Drug_add) File lib/python/DocumentTemplate/DT_String.py, line 528, in __call__ (Object: Drug_add) File lib/python/DocumentTemplate/DT_With.py, line 133, in render (Object: Drug.createInObjectManager(REQUEST['id'], REQUEST)) File lib/python/DocumentTemplate/DT_Util.py, line 337, in eval (Object: Drug.createInObjectManager(REQUEST['id'], REQUEST)) (Info: REQUEST) File <string>, line 0, in ? File lib/python/ZClasses/ZClass.py, line 452, in createInObjectManager (Object: Drug) File lib/python/OFS/CopySupport.py, line 442, in _setId (Object: asdasd) File lib/python/Products/ZPatterns/DataSkins.py, line 208, in __set_attr__ (Object: asdasd) KeyError: (see above) -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Porting EMarket to ZPatterns....
by Steve Spicklemire 27 Aug '00

27 Aug '00

Well.. I've started down the long winding road of porting EMarket to ZPatterns. I'm sure I'll learn a lot. ;-) Every time I start something I discover that my understanding is shakey.. but getting less so as time goes on.. Here is a concrete problem. (I always work better with concrete problems... even though I occasionally aspire to an abstract thought or two... that usually comes later...) I've got a class: class Shopper( OFS.SimpleItem.Item, ZPatterns.DataSkins.DataSkin, Acquisition.Implicit, AccessControl.Role.RoleManager, ): As you can see this class now inherits from data skin. I've got a specialist that manages the shopper objects. My previous constructor looked like this: def __init__(self, id, email, name, passwd, address='', city='', state='', phone='', fax='', country='', zip='', company='' ): """ Create a new shopper instance. """ # self.id=id self.email = email self.name = name self.passwd = passwd self.address = address self.city = city self.state = state self.phone = phone self.fax = fax self.zip = zip self.company = company self.country = country self.transNum = 1 self.transDict = {} self.basket = Basket(self) # firm offers... self.pendingBasket = Basket(self) # not yet firm offers.... self.pendingBasket.ClearTransaction() self.salesItems = SalesBooth(self) self.transID = self.createTransID() self.addTime = time.time() and my addShopper method used to look (essentially) like this: def addShopper(self, id, email, name, passwd, passwd2, address, city, state, phone, fax, country, zip, REQUEST=None, company = '', passExcept = 0, noCheck = 0): """Add an shopper to a folder The argument 'self' will be bound to a folder. The arguments, 'id', 'passwd', and 'passwd2' just get us started... """ # # a bunch of code to validata passwords etc.... and then... # newShopper = Shopper(id, email, name, passwd, address, city, state, phone, fax, country, zip, company) self._setObject(id, newShopper ) # get a 'result' blah blah... return result Moving this to ZPatterns brings up all sorts of questions. First of all I no longer know that the actual class stored my shopper specialist is a 'Shopper'. It could be any class kept in the shopper manager's rack(s). Soo... my addShopper should probably become: def addShopper(self, id, REQUEST): """ add a new shopper... self is now the shopperManager (Specialist) """ newShopper = self.newItem( id ) newShopper.propertysheets.methodToUpdatePropertySheetsFromMappingObject( REQUEST ) Looking through VirtualSheets and PropertySheets code I see __propsets__ so I was thinking something like: for prop in newShopper.propertysheets.__propsets__(): setattr(newShopper, prop, REQUEST.get(prop,None)) but this doesn't seem to work.... (I get 'nameError 'client'') in the debugger.... I have no clue where 'client' comes from, reminds me of the 'DTML Method' argument called 'client'... but I don't see a traceback in the debugger.. anyway.. I've come to something like this, though it doesn't do what I need.... : newShopper = self.newItem(id) newShopper.passwd = passwd newShopper.propertysheets.manage_addPropertySheet(id='EMarketProps', ns='') emp = newShopper.propertysheets.get('EMarketProps') emp.manage_addProperty('email', '', 'string') emp.manage_addProperty('name','','string') # # ... blah blah blah... # emp.manage_changeProperties(REQUEST) self._setObject(id, newShopper) I am hopeful that this will expose a glaring misconception of mine about propertysheets. ;-) Someone please tell me how stupid I am and what I'm missing here... This does me no good... since I have to create the propertysheets and I want to allow for properties that I *don't know about* (i.e., customizations that individual applications need to make these 'shoppers' work as 'clients' or 'memebrs' or whatever else...) Clearly I'm flailing here.. Any ideas from the wizards of Z? How would you modify addShopper to make it work with other applications and allow for multiple propertysheets that need to be set up from the addShopperForm.... Also.. I'm hoping for some advice about the old 'Basket' object. Basically the old basked object was a simple container, one for each shopper, that held 'Basket Items' which were essentially references to MarketItems, that were on sale in the store, along with quantity, options, etc.. How should I work these in with ZPatterns? Should there be a BasketManager for each shopper that is essentially a Specialist for BasketItems? Other ideas welcome... thanks, -steve

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bug in CatalogAwareness?
by Steve Alexander 27 Aug '00

27 Aug '00

I just checked out the latest Zope 2 CVS. In lib/python/Products/ZCatalog/CatalogAwareness.py, the method "url": def url(self, ftype=urllib.splittype, fhost=urllib.splithost): """Return a SCRIPT_NAME-based url for an object.""" if hasattr(self, 'DestinationURL') and \ callable(self.DestinationURL): url='%s/%s' % (self.DestinationURL(), self.id) else: url=self.absolute_url() type, uri=ftype(url) host, uri=fhost(uri) script_name=self.REQUEST['SCRIPT_NAME'] __traceback_info__=(`uri`, `script_name`) if script_name: uri=filter(None, string.split(uri, script_name))[0] * if uri[0] != '/': uri = '/' + uri * uri=uri or '/' return urllib.unquote(uri) I'm suspicious of the two lines marked with a "*". The line uri=uri or '/' seems to imply that url can be the empty string, or possibly None. However, the line before if uri[0] != '/': uri = '/' + uri Will fail with an IndexError if uri is ''. Perhaps the two lines ought to be replaced with: uri=uri and uri[0]!='/' and '/'+uri or uri or '/' and perhaps a comment # input output # None '/' # '' '/' # '/' '/' # 'foo' '/foo' # '/foo' '/foo' This is now in the Collector: http://classic.zope.org:8080/Collector/1551/view -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Bug in error logging in Catalog
by Steve Alexander 27 Aug '00

27 Aug '00

Zope 2.2.1, lib/python/Products/ZCatalog/Catalog.py When there is an error uncataloging an object, uncatalogObject() attempts to log the fact with this line: LOG('Catalog', ERROR, ('uncatalogObject unsuccessfully ' 'attempted to uncatalog an object ' 'with a uid of %s. ' % uid)) However, if uncatalogObject has been passed a tuple, the error logging will fail with "TypeError Error Value: not all arguments converted". The fix is to change the line to: LOG('Catalog', ERROR, ('uncatalogObject unsuccessfully ' 'attempted to uncatalog an object ' 'with a uid of %s. ' % `uid`)) or, to fit with the rest of the calls to LOG in Catalog.py: LOG('Catalog', ERROR, ('uncatalogObject unsuccessfully ' 'attempted to uncatalog an object ' 'with a uid of %s. ' % str(uid))) -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net

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Re: [Zope-dev] Porting EMarket to ZPatterns....
by Steve Spicklemire 27 Aug '00

27 Aug '00

Thanks Phillip! OK. that helped a lot. The problem is that when things don't work as I expect.. I guess (usually with a high degree of success) that I am off base. Now I've just been experimenting with this in a simpler 'dtml-only' way just to clarify how it's supposed to work. I created a simple ZClass with no ZClass based propertysheets. (The ZClass is called MyTestSkin, subclass of DataSkin) I created a specialists that manages instances of this ZClass. (The specialist is called myTest) I set up the default rack of myTest with a PlugIn SheetProvider with "SheetNames" set to "ShopperData". Based on your last email the addShopper method in 'myTest' looks like this: <dtml-var standard_html_header> <h2><dtml-var title_or_id> <dtml-var document_title></h2> <dtml-let newObj="newItem(REQUEST['id'])"> <dtml-if "newObj.propertysheets.manage_addPropertySheet(id='ShopperData',ns='')"> <dtml-let newPPS="newObj.propertysheets.get('ShopperData')"> <dtml-call "newPPS.manage_addProperty(id='email',type='string',value='')"> <dtml-call "newPPS.manage_addProperty(id='passwd',type='string',value='')"> <dtml-call "newPPS.manage_addProperty(id='address',type='string',value='')"> <dtml-call "newPPS.manage_changeProperties(REQUEST)"> New Shopper Added! <form action="<dtml-var "myTest.absolute_url()">"> <input type=submit value="OK!"> </form> </dtml-let> <dtml-else> Cannot add property sheet. </dtml-if> </dtml-let> <dtml-var standard_html_footer> It seems to work OK. Now.. the index_html for my ZClass wants to look like this: <dtml-var standard_html_header> <h2><dtml-var title_or_id> <dtml-var document_title></h2> <p> email: <dtml-var "email"><br> address: <dtml-var "address"><br> </p> </dtml-let> <dtml-var standard_html_footer> But I get 'KeyError" on any attribute. I guess I thought that the SheetProvider would kick in when a request was made for 'email' and automagically search the instances propertysheets for an attribute that matched. The following did work however: <dtml-var standard_html_header> <h2><dtml-var title_or_id> <dtml-var document_title></h2> <dtml-let myPPS="propertysheets.get('ShopperData')"> <p> email: <dtml-var "myPPS.getProperty('email')"> address: <dtml-var "myPPS.getProperty('address')"> </p> </dtml-let> <dtml-var standard_html_footer> This doesn't seem quite right to me... when I use a GenericAttributeProvider that talks to a database... I can just say <dtml-var foo> and it works. I'm sure I'm still not getting something... but I don't know what. I can look at: /myTest/a/propertysheets/ShopperData/manage and it allows me to edit the instance's property sheet through the web.. I was hoping (and maybe this is really really just wrong...) that there was some 'central' propertsheet that could be modified and thereby give all instances new properties.. sorta like ZClass property sheets... Anyway.. I'm now off to try SkinScripts with these test cases... thanks! -steve

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