[Zope] Re: Appending to a file via manage_edit?

[Josef Meile]

>> I've been looking around for this, but can't seem to find anything.  I'm
>> assuming that it is just not possible, but thought I'd ask just in case.
>>
>> For File objects, I see that manage_edit() has the parameters: title,
>> content_type, precondition, filedata & REQUEST.  Setting something in the
>> filedata parameter will replace the file's current data with that.
>>
>> This implies (to me at least) that the only way one can edit a file is a
>> complete rewrite.  Does there exist a way to simply append data to the 
>> end
>> of the file?  For instance, if one wanted to write to a file line by 
>> line,
>> is that possible in Zope?
> 
> out-of-the-box: NO
> 
> Appending data would require the manipulation of the linked list of Pdata
> elements. There is no API for this available...so basically forget it.
What about the python pickle/cpickle and marshal modules? If I'm not
wrong zope uses cpickle to append data to the Data.fs, or am I wrong?

I haven't read the module documetation deeply, but as I understand,
pickle/cpickle is used for serializing python objects, while marshal is
for binary data.

http://docs.python.org/lib/module-pickle.html
http://docs.python.org/lib/module-marshal.html

Anyway, you still need to load the whole file into a temporal memory.

Best regards
Josef