[Python-Dev] PEP 273: Import Modules from Zip Archives

[Finn Bock]

[me]

> In the current implementaion in jython, we can put python modules under
> any path and add the zipfile!path to sys.path:
> 
>    sys.path.append("/path/to/zipfile.zip!Lib")
> 
> which will look for Lib/Q/R/modfoo.py (and Lib/Q/R/modfoo$py.class) in
> the archive.

[GvR]

>Maybe it's possible to allow "/path/to/zipfile.zip/subdirectory/etc/"
>in sys.path?  That sounds better than picking a random new character
>as delimiter.

Fine by me. From a java POV the bang ("!") was not random:

>>> import java
>>> java.lang.Class.getResource(type(1), "/java/lang/Class.class")
jar:file:/D:/java/jdk1.4/jre/lib/rt.jar!/java/lang/Class.class
>>>

The URL library in java can of course open the string above as an input
stream.

>> Would entries in the static python dict be removed when a zipfile is
>> removed from sys.path? 
>
>It can be arranged that they are removed at some later point
>(e.g. when sys.path is next searched).

An API to do this could be usefull for jython. Right now we depend on
the GC thread to close the file. Since files are a limited resource it
would be a good thing to have an explicit way to clean up the cached
resources.

I don't expect the lack of a cleanup method to be a huge problem in real
life.

>> What is the __path__ vrbl set to in a module imported from a zipfile?
>> Can the module make changes to __path__ and will be changes to used when
>> importing submodules?
>> 
>> What value should __file__ have?
>
>IMO these two questions are answered by the pathname semantics
>that Jim proposes: __file__ = "/C/D/E/Archive.zip/Q/R/modfoo.pyc" and
>__path__ = ["/C/D/E/Archive.zip/Q/R"].

Ok.

I assume that as long as some module exists with a __path__ like this,
it not possible to clear the cached entries for /C/D/E/Archive.zip.

If importing from zip is regarded mainly as a deployment/bootstrapping
feature, then the cleanup issues does not exist. I have no problem
looking at it as a deployment feature (that is all I need it for
myself), I just didn't dare to put such a limit on my jython
implementation.

regards,
finn