Implementation of LDAPControls

[Michael Ströder]

Ingo Steuwer wrote:
> 
> To fulfill our upcomming goals we need to use LDAPControls, but the
> latest released version of python-ldap doesn't support them. 

Yes, you'll find a hint in file TODO.

> We did some experimental implementations in the C-backend (for "proof of
> concept") and would now like to define a general approach. This should
> be done in coordination with you to see our work in upcoming versions of
> python-ldap.

Since I'm not a C programmer (David wrote the C code) I'd be really glad 
if someone would jump on in and contribute code for LDAP controls and 
extended operations.

I already tried to wrap the arguments whereever appropriate. Please 
review this.

> My attempt would defining a python-class LDAPControl (containing OID,
> iscritcal and value (dictionary)) and implement a correspondig wrapper
> to *LDAPControl.

But value can be a complex ASN.1 structure as well.

> I think the most diffcult part will be the
> representation of berval/berelement in python.

Yes.

> - is there somebody else implementing this (I didn't look at the cvs) ?

No. And I'm currently rather short on time. I'd highly appreciate your 
contributions. But note that you should give away copyright for your 
contributed code. Make sure that your legal department agrees on that.

> - are there already thoughts, definitions or an approach I should know ?

There are several approaches.

1. Python classes for controls with a method berencode(). This method 
would be called before passing the controls as argument to the functions 
in _ldap. This would be the most flexible approach and independent of 
the underlying OpenLDAP API. Drawbacks are that you need a BER module 
for this and it's much work for complex controls.

1.a Wrap libber.

1.b Implement a pure Python BER module. Maybe we could get one from a 
SNMP implementation implemented in Python?

2. We could also wrap the helper functions in libldap (see controls.c, 
vlvctrl.c, sortctrl.c). But this would add another strong dependency on 
the OpenLDAP libs.

> - do you know about wrappers between berval/berelement and python ?

No. You could try to wrap OpenLDAP's libber.

Ciao, Michael.