Armin is a true WSGI believer. And he’s part of the Pocoo team: jinja, werkzeug, sphinx and so on.
He asked for a show of hands: how many people are already using python 3 in some way? Perhaps 5% of the hands went up…
WSGI (pronounced “wiskey”) is pep 333. Almost every web framework is using it now. WSGI is a gateway interface, we’re currently expecting too much out of it if you look at how it is used. Middleware (plug-ins) is often abused.
There are some, partially theoretical, WSGI issues like input stream is not delimited, some read()/readline() issue, path info is not URL encoded. And a small, mostly unused, part of the http protocol isn’t implemented. In the real (Django) world, most of the issues aren’t a problem.
The biggest difference in Python 3 is the string handling. You now either
have a bytestring or unicode. Every string is now unicode: everything
not-unicode is explicitly an encoded bytestring. Explicit is better than
implicit. A problem is that
stdin is now a string (so: unicode) input.
And stdin is used for cgi: so you cannot receive binary data anymore, sigh.
And URIs also aren’t unicode based. Summary:
urllib is unicode.
sys.stdin is unicode.
os.environ is unicode (only new windows versions are unicode OSs).
http and wsgi are not unicode.
The result is that the reference wsgi server in standard python 3 is now, well, broken. In the end, python 3 was supposed to make unicode easier but in the wsgi case, it is causing a lot more problems than unicode environments on python 2. WSGI on python 3 is not possible at the moment.
Armin showed some changes that have to be made to get it working. Mostly you have to do a lot more encode/decode combinations to please the standard library. And partially you have to implement your own originally-stdlib functionality.
What Armin thinks will happen:
stdlib won’t be used that much in WSGI apps.
Writing middleware becomes a whole lot harder if not impossible.
Frameworks will probably reimplement urllib and cgi stlib modules.
Probably WebOb will be used by frameworks to get a standard way to work around the problem
Armin’s pony request: get involved in wsgi and play with the specification. Subscribe to web-sig.
Armin himself is probably not going to use python 3 himself anytime soon. But he dislikes it when python fractures in a python 3 community for desktop applications and python 2 for web applications. The python 3 stdlib is currently incredibly broken but because there are so few users, these bugs stay under the radar. Also read up on Graham’s posts about this topic.
My name is Reinout van Rees and I work a lot with Python (programming language) and Django (website framework). I live in The Netherlands and I'm happily married to Annie van Rees-Kooiman.
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