Re: "Per-user" polymorphism -- newbie question

Al Pacifico wrote:

>is authorized and what he/she is authorized to do is determined by a lookup
>in an external resource (for this application, an LDAP directory). The level
>  
>
ok.

>I'd like to make my content served by Quixote essentially polymorphic,
>determined by the role the user takes. This points me in the direction of
>  
>
yes,

>subclassing a base class for each role. I imagine q_lookup() would call a
>method within a class determined by the client's role.
>  
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or just having several instances of the same class, but with different 
parameters?

hm, do you mean something like:

#this is totally untested and not too much thought of either..

class Content:
    """ Basic content class - also defines the interface."""
    def __init__(self, text):
         self.text = text

class PolymorphicContent:
    """ Content that has many versions for e.g. different people based 
on roles / clearance. """
    def __init__(self, role2text):
        self.role2text = role2text

    def get_text(self):
        requester = Requester(quixote.get_request().get_user())
        return self.role2text[requester.role]
    text = property(get_text)

frontpage = PolymorphicContent({ \
    'anonymous': 'Welcome, do %s an accout' % href(register()),
    'user': 'Welcome back, %s' % user,
    'admin': 'Currently logged in are: %s' % users
}

def _q_index():
    return frontpage.text

?

>each class will have a set of stylesheets that are class attributes derived
>from class methods (pardon me if my OO-terminology is a bit off, but what I
>mean is every instance of a given class will share the same set of
>stylesheets, each a singleton). The libxml2 and libxslt modules seem to work
>really well for this.
>  
>
the terminology sounds sane .. if you wanna have some attribute, e.g. 
the stylesheet used, the same for all instances of a class, it makes 
sense to have it as a class attribute. and they can be derived from 
'class methods' .. i guess that's static methods in python (or just 
functions?)

>Is this problem really as trivial as it seems?
>  
>
i don't get that part on xml processing really, but didn't see anything 
that would make this non-trivial :)

>Before experimenting with my own ideas, I'd like to solicit ideas about how
>others would incorporate this into a q_lookup() method?
>Thanks in advance.
>  
>
i didn't really think of that (the code example above is just .. trying 
to illustrate your question)

dunno if it might be relevant or interesting for you or anyone here, but 
i have a related publication draft about some old research we did on 
this a while ago .. really simple basic stuff, 
http://an.org/owla/jodi.html 'Visual specification of adaptive 
hypermedia' but connected to OO design too.

>-al
>
~Toni