[lxml-dev] LXML and persistence with the ZODB?

[Martijn Faassen]

Martijn Faassen wrote:
> Marius Gedminas wrote:
>> On Thu, Jun 26, 2008 at 04:50:30PM -0500, Kenneth Miller wrote:
>>> Anyone done anything with this? I know it's simple enough to simply  
>>> store an XML string, but has anyone bothered with storying lxml objects?
>> I wouldn't even try.  ZODB is tricky to get right, especially if you're
>> trying to store mutable objects not designed to be stored in the ZODB.
>> And if future-compatibility with your old database is important, you
>> must commit to never renaming a class or an attribute, which is hard to do
>> when you rely on an external library without such commitment.
> 
> Actually we're pickling a very well known data structure, XML, not a 
> tree of elements. You could therefore write a pickler that takes 
> advantage of this particular property. You'd only worry about the outer 
> class name at most.

Checking the lxml.objectify code, it's indeed using this strategy. Since 
libxml2 serialization and deserialization of XML is pretty fast, this 
should be okay to use in a pickler.

Regards,

Martijn