On Apr 26, 2005, at 8:24 PM, Guido van Rossum wrote:
Someone should think about rewriting the zipfile module to be less hideous, include a repair feature, and be up to date with the latest specifications <http://www.pkware.com/company/standards/appnote/>.
-- and allow *deleting* a file from a zipfile. As far as I can tell,
you now can't (except by rewriting everything but that to a new zipfile
and renaming). Somewhere I saw a patch request for this, but it was
languishing, a year or more old. Or am I just totally missing
something?
Please don't propose a grand rewrite (even it's only a single module). Given that the API is mostly sensible, please propose gradual refactoring of the implementation, perhaps some new API methods, and so on. Don't throw away the work that went into making it work in the first place!
Well, I didn't necessarily mean it should be thrown away and started from scratch -- however, once you get all the ugly out of it, there's not much left! Obviously there's something wrong with the way it's written if it took years and *several passes* to correctly identify and fix a simple format character case bug. Most of this can be blamed on the struct module, which is more obscure and error-prone than writing the same code in C.
One of the most useful things that could happen to the zipfile module would be a stream interface for both reading and writing. Right now it's slow and memory hungry when dealing with large chunks. The use case that lead me to fix this bug is a tool that archives video to zip files of targa sequences with a reference QuickTime movie.. so I end up with thousands of bite sized chunks.
This >2GB bug really caused me some grief in that I didn't test with such large sequences because I didn't have any. I didn't end up finding out about it until months later because client *ignored* the exceptions raised by the GUI and came back to me with broken zip files. Fortunately the TOC in a zip file can be reconstructed from an otherwise pristine stream. Of course, I had to rewrite half of the zipfile module to come up with such a recovery program, because it's not designed well enough to let me build such a tool on top of it.
Another "bug" I ran into was that it has some crazy default for the ZipInfo record: it assumes the platform ("create_system") is Windows regardless of where you are! This caused some really subtle and annoying issues with some unzip tools (of course, on everyone's machines except mine). Fortunately someone was able to figure out why and send me a patch, but it was completely unexpected and I didn't see such craziness documented anywhere. If it weren't for this patch, it'd either still be broken, or I'd have switched to some other way of creating archives!
The zipfile module is good enough to create input files for zipimport.. which is well tested and generally works -- barring the fact that zipimport has quite a few rough edges of its own. I certainly wouldn't recommend it for any heavy duty tasks in its current state.
-bob
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