[Zope] adding dtml/zpt methods to product classes

[Pascal Peregrina]

Why don't you simply define the DTML/ZPT objects attributes outside any
class method ?

class HyperTextArea(Implicit, Globals.Persistent, RoleManager, Item): 
	my_method = Globals.HTMLFile("dtml/my_method",globals())
	my_new_method = Globals.HTMLFile("dtml/my_new_method",globals()) 
	...

This is what I do, and any new DTML/ZPT object I define that way gets added
to any existing instance of this class type when I restart Zope (or when
refresh my product).

Pascal


-----Message d'origine-----
De : zope-bounces+pperegrina=lastminute.com at zope.org
[mailto:zope-bounces+pperegrina=lastminute.com at zope.org]De la part de Keith
Alperin
Envoyé : vendredi 28 janvier 2005 04:59
À : zope at zope.org
Objet : [Zope] adding dtml/zpt methods to product classes


Greetings Zopistas! 


I have been a Zope tinkerer for a few years and have never been able to
adequately solve this problem: When I create a Product class with DTML/ZPT
methods, how can I make those methods members of the class rather than
simply instance methods? These examples should illustrate what I mean. 


My first try was like this: 
class HyperTextArea(Implicit, Globals.Persistent, RoleManager, Item): 
        def __init__(self,resourcePath, imageFolder): 
               self.my_method = Globals.HTMLFile("dtml/my_method",globals())



That works fine until you want to add a new method to your class like so: class HyperTextArea(Implicit, Globals.Persistent, RoleManager, Item): 
        def __init__(self,resourcePath, imageFolder): 
               self.my_method = Globals.HTMLFile("dtml/my_method",globals())

               self.my_new_method =
Globals.HTMLFile("dtml/my_new_method",globals()) 


new instances of your product will get the my_new_method, but instances that
have already been created will not. 


My second try was like this: 
class HyperTextArea(Implicit, Globals.Persistent, RoleManager, Item): 
        def my_method(self, REQUEST): 
                """ template """ 
                if (not hasattr(self,"my_method_member")): 
                        self.my_method_member =
Globals.DTMLFile("dtml/my_method",globals()) 
                return self.my_method_member(self,REQUEST) 


This allows me to add methods to the class at any time and all instances
will get the method. However, for some reason, when I use this pattern, i
get strange acquisition results (for example, some of my objects children's
dtml methods will use the parent's namespace for lookups). 


Currently, I'm doing this: 
class HyperTextArea(Implicit, Globals.Persistent, RoleManager, Item): 
        def my_method(self, REQUEST): 
                """ template """ 
                self.my_method_member =
Globals.DTMLFile("dtml/my_method",globals()) 
                return self.my_method_member(self,REQUEST) 
which seems ugly, and like it might have performance problems, but i haven't
had any acquisition problems yet. 


My real question here is: What is the standard way to handle this problem of
being able to add dtml/zpt methods to classes such that all instances of
those classes get the new methods? 


Thanks in advance for any insight. 


Sincerely, 
Keith Alperin 


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