Re: [Zope] __bobo_traverse__ (Cont.)

31 Aug 2004

      Johan Carlsson wrote:
...
Garito wrote:
...
Hi
In my last mail I ask you (thanks for your responses) about an error 
publishing the object in __bobo_traverse__
The solution passes by returning an object instead a string (I would 
like to return a string :( )
Then my __bobo_traverse__ is something like:
def __bobo_traverse__(self, REQUEST, name):
   obj = getattr(self, name, None)
       if obj is not None:
           return obj
       else:
           return getattr(self, 'Result')
But I need to process some information in bobo_traverse before 
returns Result
If you change the line return getattr(self, 'Result') for return 
getattr(self, 'Result')('someresults') doesn't work
For that I need to do something like:
_Results = dict() # I put these declaration in my class
def __bobo_traverse__(self, REQUEST, name):
   obj = getattr(self, name, None)
       if obj is not None:
           return obj
       else:
           self._Results[str(REQUEST.SESSION.id)] = self.MyResult()
           return getattr(self, 'Result')
def MyResult(self):
   """MyResult"""
   return 'This is my test result'
def GetResults(self, Session):
   """ GetResults"""
   return self._Results[str(Session)]
Then I create a Python Script called Result like:
return context.GetResults(context.REQUEST.SESSION.id)
But all these code raise:
Traceback (innermost last):
 Module ZPublisher.Publish, line 91, in publish
 Module ZPublisher.BaseRequest, line 302, in traverse
 Module Products.MyProducts.MyProduct, line 116, in __bobo_traverse__
TypeError: object does not support item assignment
I can't undersand why can't I assign a dictionary. I can understand 
if I try to assign a number like dictionary key (but I convert the 
session id to a string)
Exactly what is self._Results when you're trying to assign it.
It sounds to me that it's not what you think it is.
Remember Python is a Dynamically Typed language :-)
I'd check that anyway.
Second, from your example "return getattr(self, 'Result')" doesn't 
make sense because Result is never set (as far as the exemple code goes).
All this seems very complicated though, I think there can be a cleaner
solution (for instance returning a object that does the calculation:
def __bobo_traverse__(self, REQUEST, name):
    obj = getattr(self, name, None)
    if obj is not None:
        return obj
    else:
    brain=CalculatingBrain(REQUEST.SESSION.id, or what ever
            data is needed )
        return brain
with:
class CalculatingBrain(Implicit):
security = ClassSecurityInfo()
    security.declareObjectProtected(View) #Or what ever.
    def __init__(self, session_id, or what ever):
    pass or do stuff
def MyProduct(self, REQUEST=None):
    """You could even make this traversable if you'd like"""
    return 'Result'
Thanks again Johan for your response
getattr(self, 'Result') is a python script inside my product (my product
is a container)
I can't undersant the complexity in these case
Perhaps could be interesant to explain what I try to do before continue
these conversation
I try to process TraversalRequestNameStack (traverse_subpath) as user query
Then I would like to generate the response and serve it to the user
For example:
user tye some thing like:
http://myserver:myport/MyProduct/Value1
User wants Value1 in MyProduct
Value1 is a processed value that returns: 'This is the result of
precessing Value1'
How could I do it? (Perhaps with these point of view we can understand
ourselves better)

My thoughts:
Override __bobo_traverse__ to process TraversalRequestNameStack because
traverse_subpath is not available in products
Then return the results to be printed in the screen

I assume these would be truly in fact easier :'(

These explanation illuminate you? (I hope so!!!)

THANKS AGAIN

PD: Sorry for my english!