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Enhancing Zipapp


Note: draft simplified

Abstract
======

This extracts aims at proposing enhancements to the generated zipapp
executable

Rationale
=======

One area where there remains some difficulty in Python is packaging for
end-user consumption. To that effect either the code is distributed in pure
Python form with installers [1] or native executables are built for each
target
Os [2]. Currently by default, Python does not provide such utilities. This
pro-
posal aims at finalising a Python-specific archive as the default VM exec-
utable built on zipapp.

In simple terms, it proposes to enhance zipapp from plain archive to
app-level
archive.

Advantages of archives
==================

Archives provide a great way to publish software that needs to be
distributed as
a single file script but is complex enough to need to be written as a
collection of
modules [3]

You can use archives for tasks such as lossless data compression,
archiving,
decompression, and archive unpacking. [4] Adding capabilities like digital
signing is used to verify integrity and authenticity.

Zip archives as apps
================

If we are to treat zip archives as app, here are some recommended features

- [x] Main entry point

A main entry point specifies which file to launch. Zipapp already solves
this
problem by either having a __main__.py [5] or specifying the entry point at
the
commandline ENTRYPOINT_MODULE:ENTRYPOINT_FUNCTION [6]

- [  ] App info file

An info file can have info such as author name, archiving date, company name
etc.

- [  ] Signing mechanism

Mechanisms can be added to detect the integrity of the app. App hash can be
used to check if the app has been modified and per-file hash can be used to
detect what part has been modified. This can be further enhanced if needed.

- [  ] Protecting meta data

Metadata are not protected by basic signing. There existing ways to protect
metadata and beyond [7]

 - [x] Pure-Python 3rd party package bundling

In Python, as long as the 3rd party packages are pure-python packages, we
can bundle and use them [6]. The user can maybe just include a
requirements.txt

- [  ] C-based 3rd party packages

Zipapp by default was not meant to include packages at all.

<< The executable zip format is specifically designed for standalone use,
without needing to be installed. They are in effect a multi-file version of
a
standalone Python script >>

Though the previous point shows that this can be done. Now remains the
issue of C-based packages. Distributing wheels might be the answer [8].
A zip archive is supposed to be standalone. A possible  solution might be
to
include wheels and the wheels are installed in a site-packages folder.

When running such an app, the interpreter will check first if the
app-specific
site-packages folder is empty, if not, install the wheels. This provides
package-
freezing ability. The only downside is longer first-run time.

Only specifying packages to be installed is not an option as if you really
want
stand-alone apps, using the internet etc defeats the purpose.

FAQ
====

Why not a package manager?
---------------------------------------
The zipapp pep was introduced for a reason, for easing the running of
archives.
Maybe the package manager idea came from listening to people talking about
packaging and pex and comparing it with package-managers like homebrew
and concluded that pex and hence zipapp is not worth it and people would
better off not complicate their lives with some zip utility.

This proposal is not solving any problem at all
--------------------------------------------------------------
This proposal aims at enhancing zipapp. Zipapp solved the problem. Zipapp
had an aim. This proposal aims at helping zipapp better accompplish it's
aim.


References

[1] https://pynsist.readthedocs.io/en/latest/

[2] https://www.pyinstaller.org

[3] https://www.python.org/dev/peps/pep-0441/

[4] https://docs.oracle.com/javase/tutorial/deployment/jar/basicsindex.html

[5] https://docs.python.org/3/library/zipapp.html

[6] https://gist.github.com/lukassup/cf289fdd39124d5394513a169206631c

[7] https://source.android.com/security/apksigning

[8] https://pythonwheels.com



Yours,

Abdur-Rahmaan Janhangeer
pythonmembers.club <http://www.pythonmembers.club/> | github
<https://github.com/Abdur-rahmaanJ>
Mauritius