[Python-Dev] Zipping Zope3

[Moore, Paul]

From: Guido van Rossum [mailto:guido@python.org]

>> My specific issue is with get_data, which is totally unneeded
>> for the import protocol itself (although it does solve real,
>> related issues). I don't think it should be a requirement of
>> the import hook API. Documenting it as an optional interface
>> which hooks may choose to support may be reasonable, though.

> I like get_data(). The caller should always be prepared for
> it to return an error (how does it do that? raise what? or
> return None? that should be specified!). An importer that
> can't do this should implement a version that always reports
> an error. This is much easier on the client than calling
> hasattr(importer, 'get_data') first or catching AttributeError.

I don't have a big problem with get_data(). But currently, it's
badly under-specified. You mention the question of how it returns
errors (not just "can't do this" - what about "file not found"?).
There's also the question of the exact format of the "filename".
Should it be like a module name (dotted)? This has the advantage
of matching how the rest of the importer logic works, but the
disadvantage of being unnatural to the user. Should it be a
pseudo-path format? This has the disadvantage of being platform
specific (the zipimporter already jumps through some hoops to
convert os.sep/os.altsep into forward slashes (which is what the
zip format uses), and other importers may have even more work to
do). Or something else?

Also is it a method of the object that implements load_module, or
the one that implements find_module? I could argue either. I can
code things either way. But I don't have enough "real world"
experience to say which is best in practice.

Paul.