wsgi closing connections

app.py

"""
Start with:

    gunicorn app:application

or:

    python app.py

Then:

    curl -v -N http://127.0.0.1:8000/

What you should see is a slow trickling of an upper case alphabet
and then a closed connection.

Interestingly gunicorn claims chunked Transfer-Encoding but wsgiref
does not. If you use telnet to make a raw GET / HTTP/1.1 request
you can see that gunicorn is using chunked encoding, wsgiref is not.
The behavior of the final output is not different.
"""

import sys
import time
from wsgiref.simple_server import make_server


def handler(environ, start_response):

    start_response('200 OK', [('content-type', 'text/plain')])
    
    for i in 'abcdefhijklmnopqrstuvwxyz':
        yield '%s\n' % i
        time.sleep(0.5)


class UpperMiddleClass(object):

    def __init__(self, application):
        self.application = application

    def __call__(self, environ, start_response):
        return (output.upper() for output in
                self.application(environ, start_response))


application = UpperMiddleClass(handler)

if __name__ == '__main__':
    httpd = make_server('', 8000, application)
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        sys.exit(0)