This sounds like a valuable refactoring to me. Is it API compatible with the current zipfile module docs?
On Mon, 3 Jun 2019, 20:23 Daniel Hillier, <dhillierc...@gmail.com> wrote: > Hi, > > I've written a package that can read and write zip files encrypted with > Winzip's AES encryption scheme (https://github.com/danifus/pyzipper/). It > is > based on Python's zipfile module which I refactored to facilitate adding > the > AES code as subclasses of the classes defined in the zipfile module. > > I would like to explore integrating some of the refactoring effort into > Python > if they are wanted. While the AES specfic code probably isn't suitable for > integration due to its dependence on a crypto package, my hope is that the > refactor of the zipfile project may be beneficial and, in particular, help > development on other features of the zip spec. I'm happy to rework the > changes for inclusion in Python. > > The general goals of the refactor were: > - Keep the AES implementation changes in a separate file so changes to > zipfile.py could potentially be merged into Python (the cryptically named > "minimal_pep8" branch contains minimal cosmetic changes to the code > unless the lines around it were changed. The master branch contains all > the > changes in the minimal_pep8 plus pep8 and a few other changes). > - Add hooks for extending the way zipfile works to enable the addition of > AES > encryption without having to duplicate most of the zipfile module. This > included adding hooks to: > - Select and call encrypt and decrypt methods. > - Read and write new "extra" data records in the central file directory > and local header records. > - Provide a mechanism to substitute ZipInfo, ZipExtFile and > ZipWriteFile > classes used in a subclass of ZipFile to ease use of subclassed > ZipInfo, > ZipExtFile or ZipWriteFile. This avoids having to rewrite large > parts of > the zipfile module if we only want to change the behaviour of a small > part of one of those classes. > - Contain all code that reads the header, contents and tail of a file in > the > archive to within ZipExtFile. Previously reading the header and some > other > things were done in the ZipFile class before handing the rest of the > processing to ZipExtFile. > - Contain all code that writes the header, contents and tail of a file in > the > archive to within ZipWriteFile. Previously reading the header and some > other > things were done in the ZipFile class before handing the rest of the > processing to ZipExtFile. > - Move generation of local file header and central directory record > content to > the ZipInfo class to be alongside the data that it is packing. > - Add comments to provide context from the zip spec. Replace explicit > numbers > to variables with explanatory names or adding comments. > > Concerns: > - The change set is not small. I've attempted to keep each commit in the > minimal_pep8 branch focused on a single change to simplify review and > kept > the unrelated changes, like pep8, to a minimum. I'm happy to put in > the work to > get these changes into a patch for the Python project, if it is deemed > useful. > - This could move the internals of zipfile towards a public API (maybe it > would be?) which brings additional complexity in managing future changes. > - Are the hooks inline with Python's coding style? Is there a different > approach to extensibility preferred within the Python project? > > Let me know any improvements, suggestions or concerns to this refactoring > approach you may have. Happy for feedback even if it isn't about > integrating the > code into Python. > > Thanks, > Dan > _______________________________________________ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ >
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