[Web-SIG] A more useful command-line wsgiref.simple_server?

[Graham Dumpleton]

On 29 March 2012 21:02, Masklinn <masklinn at masklinn.net> wrote:
> Moving here as suggested by Terry Reedy as this list may be more
> interested than -ideas (note: some feedback already used to revise
> the original proposal, and a very basic patch — with no tests — is
> provided for the current CPython default branch)
>
> Currently, calling wsgiref.simple_server simply mounts the (bundled)
> demo app.
>
> I think that's a bit of a lost opportunity: the community seems to have
> mostly standardized on a wsgi script providing an application callable
> in its global namespace (though details may differ, mod_wsgi does not
> care for the script's name and mandates an `application` callable while

Apache/mod_wsgi only defaults to 'application', it is configurable.

As for the rest of the proposal, I tried to push the same idea a few
years back with intent that all WSGI servers would provide a similar
mechanism to that you describe as a lowest common denominator, but I
didn't get anywhere at the time.

Although people now perhaps appreciate more that a single approach
would be better, it has ballooned now into a much bigger goal with the
discussions on a common deployment mechanism. For example, a WARP file
(Python WAR file equivalent) being the latest idea. This was touched
on again at Web Summit at PyCon this year.

Graham

> e.g. gunicorn wants a Python module and the callable name must be
> configured), and it would be nice if simple_server could take such a
> script and mount the application provided:
>
> * This would allow testing that the script has no error without having
>  to go through mounting it in e.g. mod_wsgi
> * It would make trivial/test applications (e.g. dynamic responders to
>  local JS) simpler to bootstrap as there would be no need for the
>  half-dozen lines of wsgiref.simple_server bootstrapping and "hard"
>  dependency on wsgiref,
>
>   import wsgiref.simple_server
>
>   def application(environ, start_response):
>       'code'
>
>   if __name__ == '__main__':
>       httpd = make_server('', 8000, application)
>       httpd.serve_forever()
>
>  could become:
>
>   def application(environ, start_response):
>       'code'
>
> Since wsgiref already supports `python -mwsgiref.simple_server`, the
> changes would be pretty simple:
>
> * an optional positional argument of the form `script[:app]`, the script
>  is exec'd, the application (called "application" by default) is
>  extracted and then mounted in simple_server. If no script is specified,
>  just mount `demo_app` as before
> * Add -H/--host -p/--port options to, respectively, the hostname and the
>  port to bind the server to.
> * The current -msimple_server uses `handle_request` and only replies once,
>  to increase the usability of the CLI tool use `serve_forever` *when and
>  only when the mounted application is not demo_app*. It also avoids
>  opening a hardcoded example URL on launch.
>
> This way the current sanity test/"PHPInfo" demo app works as it did before,
> but it becomes possible to very easily serve a WSGI script with almost no
> overhead in the script itself.
>
> Attachment: patch performing the above-specified alterations, using
> argparse for arguments parsing and generation of help.
>
>
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