Z Classes hangup.
Hello, I recently posted a message on the Zope list asking a very important (to us) question about Z Classes, and haven't received a response, so I thought I would try zope-dev instead. I need to be able to create the following setup: Z Class: + MyBaseClass (inherits ObjectManager, isFolderish) Methods: - index_html (DTML Method) - doc_a (DTML Method) - doc_b (DTML Method) where index_html is: <!--#var doc_a--> <!--#var doc_b--> and doc_a is: This is Base Document A. and doc_b is: This is Base Document B. Now, when I make the following (in Zope Management interface): + / (Root Folder) - MyBaseClassInstance (MyBaseClass) I can browse to http://localhost/MyBaseClassInstance/index_html and see: This is Base Document A. This is Base Document B. So far so good. Now, here's where I am having problems. I need to override doc_a in the INSTANCE ONLY, like: + / (Root Folder) + MyBaseClassInstance (MyBaseClass) - doc_a (DTML Method) where doc_a is: This is Instance Document A. such that navigating to http://localhost/MyBaseClassInstance/index_html yields: This is Instance Document A. This is Base Document B. When I try to drop doc_a (DTML Method) in MyBaseClassInstance I get a "Bad Request" message, telling me the id doc_a is already in use. :( I don't want to have to make a new Z Class, and I don't want to mess with index_html or doc_b at all (though I may, in another instance, want to change index_html to reverse the order of doc_a and doc_b, or just redefine doc_b instead, etc. Each instance will be unique. Changing the base class should change all instances, except those which have overloaded the changed aspect. As I understand it, Z Classes already do this just fine.) Making a new Z Class works, but I'll end up with 300 (NOT an exageration) Z Classes, and my Zope Management UI will be quite ugly (plus, it will require all of our web developers to work in Control Panel all the time, which isn't the usual way of doing things.) I tried being a bad boy and patching the source such that _checkId's allow_dup parameter defaulted to 1, but it didn't do as I thought it would. I shouldn't be messing around in there, anyways, since I'm not very familiar with Zope's internals, yet. If only I can get this to work, my company will be using Zope on two MAJOR deals we just got. I can't mention names, now, but I promise DC would benefit from the press involved once the projects are complete. This is the only hitch in our gitty-up at the moment. How frustrating to be sooo close. :^) HEEELP! :^) Thanks, --jkh ____________________________________________________________________ Get free e-mail and a permanent address at http://www.netaddress.com/?N=1
Don't know much about ZClasses, but can't this be solved to have an empty property in the ZClass and set this when an new doc_a (doc_a2) is put into an instance. index_html can then look for the value of the property (doc_a2) or render doc_a. Just a workaround, as I think it should be possible to do this like in the aquisition case. __Janko Jeff K.Hoffman writes:
Hello,
I recently posted a message on the Zope list asking a very important (to us) question about Z Classes, and haven't received a response, so I thought I would try zope-dev instead.
I need to be able to create the following setup:
Z Class: + MyBaseClass (inherits ObjectManager, isFolderish) Methods: - index_html (DTML Method) - doc_a (DTML Method) - doc_b (DTML Method)
where index_html is:
<!--#var doc_a--> <!--#var doc_b-->
and doc_a is:
This is Base Document A.
and doc_b is:
This is Base Document B.
Now, when I make the following (in Zope Management interface):
+ / (Root Folder) - MyBaseClassInstance (MyBaseClass)
I can browse to http://localhost/MyBaseClassInstance/index_html and see:
This is Base Document A. This is Base Document B.
So far so good. Now, here's where I am having problems. I need to override doc_a in the INSTANCE ONLY, like:
+ / (Root Folder) + MyBaseClassInstance (MyBaseClass) - doc_a (DTML Method)
where doc_a is:
This is Instance Document A.
such that navigating to http://localhost/MyBaseClassInstance/index_html yields:
This is Instance Document A. This is Base Document B.
When I try to drop doc_a (DTML Method) in MyBaseClassInstance I get a "Bad Request" message, telling me the id doc_a is already in use. :(
I don't want to have to make a new Z Class, and I don't want to mess with index_html or doc_b at all (though I may, in another instance, want to change index_html to reverse the order of doc_a and doc_b, or just redefine doc_b instead, etc. Each instance will be unique. Changing the base class should change all instances, except those which have overloaded the changed aspect. As I understand it, Z Classes already do this just fine.)
Making a new Z Class works, but I'll end up with 300 (NOT an exageration) Z Classes, and my Zope Management UI will be quite ugly (plus, it will require all of our web developers to work in Control Panel all the time, which isn't the usual way of doing things.)
I tried being a bad boy and patching the source such that _checkId's allow_dup parameter defaulted to 1, but it didn't do as I thought it would. I shouldn't be messing around in there, anyways, since I'm not very familiar with Zope's internals, yet.
If only I can get this to work, my company will be using Zope on two MAJOR deals we just got. I can't mention names, now, but I promise DC would benefit from the press involved once the projects are complete.
This is the only hitch in our gitty-up at the moment. How frustrating to be sooo close. :^) HEEELP! :^)
Thanks,
--jkh
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"Jeff K.Hoffman" wrote:
I need to be able to create the following setup:
Z Class: + MyBaseClass (inherits ObjectManager, isFolderish) Methods: - index_html (DTML Method) - doc_a (DTML Method) - doc_b (DTML Method)
where index_html is:
<!--#var doc_a--> <!--#var doc_b-->
and doc_a is:
This is Base Document A.
and doc_b is:
This is Base Document B.
Now, when I make the following (in Zope Management interface):
+ / (Root Folder) - MyBaseClassInstance (MyBaseClass)
I can browse to http://localhost/MyBaseClassInstance/index_html and see:
This is Base Document A. This is Base Document B.
So far so good. Now, here's where I am having problems. I need to override doc_a in the INSTANCE ONLY, like:
+ / (Root Folder) + MyBaseClassInstance (MyBaseClass) - doc_a (DTML Method)
where doc_a is:
This is Instance Document A.
such that navigating to http://localhost/MyBaseClassInstance/index_html yields:
This is Instance Document A. This is Base Document B.
When I try to drop doc_a (DTML Method) in MyBaseClassInstance I get a "Bad Request" message, telling me the id doc_a is already in use. :(
I don't want to have to make a new Z Class, and I don't want to mess with index_html or doc_b at all (though I may, in another instance, want to change index_html to reverse the order of doc_a and doc_b, or just redefine doc_b instead, etc. Each instance will be unique. Changing the base class should change all instances, except those which have overloaded the changed aspect. As I understand it, Z Classes already do this just fine.)
The ObjectManager class doesn't let you add an object if the id of the new object matches the name of an existing attribute. This is not just true of ZClasses instances, it is true of folders and other object managers. This is a feature. I suppose you could create a mix-in class that provided a _checkId that was less restrictive. You'd want to allow the object to be added if the object didn't aleady have the id as a key in it's instance dictionary and if the name was in some list of overridable names. Alternatively, you could try one of the following approaches: 1. Ommit doc_a from the class and make it's insertion conditional: <!--#if "_.hasattr(aq_explicit, 'doc_a')"--> <!--#var doc_a--> <!--#else--> <!--#var default_doc_a--> <!--#/if--> 2. Ommit doc_a from the class and create it in the instance during construction: <!--#with "theClass.index_html(REQUEST['id'], REQUEST)"--> <!--#call "manage_addDTMLDocument( 'doc_a','', '<!--#var default_doc_a-->')"--> <!--#/with-->
If only I can get this to work, my company will be using Zope on two MAJOR deals we just got.
Cool.
This is the only hitch in our gitty-up at the moment. How frustrating to be sooo close. :^) HEEELP! :^)
I hope you are just prototyping at this point. ZClasses have some *current* limitations that make them risky for production applications. In particular: - If a ZClass instance is exported and imported, it will be disconnected from the class in Products, because the class gets exported to. In other words, the instance will have a *copy* of the class. - Because copy and paste use the same machinery as export/import, copy and paste have the same problem as described above. We plan to fix this ASAP, but it probably won't get fixed till the end of May or early June. Jim -- Jim Fulton mailto:jim@digicool.com Technical Director (540) 371-6909 Python Powered! Digital Creations http://www.digicool.com http://www.python.org Under US Code Title 47, Sec.227(b)(1)(C), Sec.227(a)(2)(B) This email address may not be added to any commercial mail list with out my permission. Violation of my privacy with advertising or SPAM will result in a suit for a MINIMUM of $500 damages/incident, $1500 for repeats.
participants (3)
-
Jeff K.Hoffman -
jhauser＠ifm.uni-kiel.de -
Jim Fulton