[Python-Dev] Require loaders set __package__ and __loader__

Christian Heimes lists at cheimes.de
Sun Apr 15 02:06:47 CEST 2012

Am 15.04.2012 00:56, schrieb Guido van Rossum:
> Well, if it's a real file, and you need a stream, that's efficient,
> and if you need the data, you can read it. But if it comes from a
> loader, and you need a stream, you'd have to wrap it in a StringIO
> instance. So having two APIs, one to get a stream, and one to get the
> data, allows the implementation to be more optimal -- it would be bad
> to wrap a StringIO instance around data only so you can read the data
> from the stream again...

We need a third way to access a file. The two methods get_data() and
get_stream() aren't sufficient for libraries that need a read file that
lifes on the file system. In order to have real files the loader (or
some other abstraction layer) needs to create a temporary directory for
the current process and clean it up when the process ends. The file is
saved to the temporary directory the first time it's accessed.

The get_file() feature has a neat benefit. Since it transparently
extracts files from the loader, users can ship binary extensions and
shared libraries (dlls) in a ZIP file and use them without too much hassle.


More information about the Python-Dev mailing list