A very simple web framework and application

simple_wsgi.py

import re
import traceback


class wsgiapplication(object):
    """Base class for wsgiapplication."""

    def __init__(self, environ, start_response):
        self.environ = environ
        self.start = start_response
        self.status = '200 OK'
        self._headers = []

    def __iter__(self):
        try:
            x = self.delegate()
            self.start(self.status, self._headers)
        except:
            headers = [('Content-Type', 'text/plain')]
            self.start('500 Internal Error', headers)
            x = 'Internal Error:\n\n' + traceback.format_exc()

        if isinstance(x, str):
            return iter([x])
        else:
            return iter(x)

    def header(self, name, value):
        self._headers.append((name, value))

    def delegate(self):
        path = self.environ.get('PATH_INFO')
        method = self.environ.get('REQUEST_METHOD')

        for pattern, name in urls:
            m = re.match('^' + pattern + '$', path)
            if m:
                args = m.groups()
                funcname = '%s_%s' % (method.upper(), name)
                func = getattr(self, funcname)
                return func(*args)

        return self.notfound()

    def notfound(self):
        self.status = '404 Not Found'
        self.header('Content-type', 'text/plain')
        return 'Not Found\n'

urls = [
    ('/', 'index'),
    ('/(.*)', 'names'),
]


class application(wsgiapplication):

    def GET_index(self):
        self.header('Content-type', 'text/plain')
        return 'Hello world!\n'

    def GET_name(self, name):
        self.header('Content-type', 'text/plain')
        return 'Hello %s!\n' % name

if __name__ == '__main__':
    from wsgiref.simple_server import make_server
    srv = make_server('localhost', 8080, application)
    srv.serve_forever()