simplify Web Server base on wsgi on gunicorn, gevent. visit eg. http://localhost/DEMO/Hello?method=Say&other=otherparameter

Hello.py

#!/usr/bin/env python
# coding:utf-8

import requsts
import imghdr, json

''' this file is in package DEMO folder '''

def Say(parameters, start_response):
    s = {
         'content': 'how are you?',
    }
    start_response('200 OK', [('Content-Type', "application/json")])
    return json.dumps(s)


def Remote(parameters, start_response):
    ''' get remote img from server-end '''
    url = parameters['img']
    r = requests.get(url)
    data = r.content
    r.close()
    imgtype = imghdr.what('', h=data)
    start_response('200 OK', [('Content-Type', 'image/{}'.format(imgtype)),
                              ('content-length', str(len(data)))])
    return [data]

Starter.py

#!/usr/bin/env python
# coding:utf-8

__version__ = '1.0.0'

try:
    import gevent
    import gevent.queue
    import gevent.monkey
    gevent.monkey.patch_all()
except ImportError:
    pass

import sys
import logging
import multiprocessing
from urllib import unquote as urlunquote


def application(environ, start_response):
    try:
        PATH_INFO = environ['PATH_INFO'].split('/')
        logging.debug(PATH_INFO)
        if not PATH_INFO[1] or len(PATH_INFO) != 3:
            data = 'hello, this is a private service.'
            start_response('200 OK', [('Content-Type', "text/plain"),
                                      ('content-length', str(len(data)))])
            return [data]
        if PATH_INFO[1] == 'favicon.ico':
            start_response('200 OK', [('Content-Type', "image/png")])
            return []

        REQUEST_METHOD = environ['REQUEST_METHOD']
        if REQUEST_METHOD == 'GET':
            parameters = parse_request_data(environ['QUERY_STRING'])
        elif REQUEST_METHOD == 'POST':
            data = environ['wsgi.input'].read()
            logging.debug(data)
            parameters = parse_request_data(data)
            logging.debug(parameters)
        else:
            start_response('403', [('Content-Type', "text/plain")])
            return ['Access denied.']

        if not 'method' in parameters:
            start_response('200 OK', [('Content-Type', "text/plain")])
            return ['not supported method.']

        module = __import__('{}.{}'.format(PATH_INFO[1], PATH_INFO[2]), {}, {}, ['models'])
        logging.debug(module)

        if 'method' in parameters:
            method = getattr(module, parameters['method'])
            return method(parameters, start_response)

        start_response('403', [('Content-Type', "text/plain")])
        return ['Access denied.']

    except Exception as e:
        logging.error(e)
        raise StopIteration


def parse_request_data(qs):
    r = {}
    for pair in qs.replace(';', '&').split('&'):
        if not pair: continue
        nv = pair.split('=', 1)
        if len(nv) != 2: nv.append('')
        key = urlunquote(nv[0].replace('+', ' '))
        value = urlunquote(nv[1].replace('+', ' '))
        r[key] = value
    return r


def number_of_workers():
    return (multiprocessing.cpu_count() * 2) + 1


def run_wsgi_app(address, app):
    try:
        from gunicorn.app.wsgiapp import WSGIApplication

        class GunicornApplication(WSGIApplication):
            def __init__(self):
                pass

            def init(self, parser, opts, args):
                return {'bind': '%s:%d' % (address[0], int(address[1])),
                        'workers': number_of_workers(),
                        'worker_class': 'gevent'}

            def load(self):
                return app
        GunicornApplication().run()
    except ImportError:
        from gevent.wsgi import WSGIServer
        WSGIServer(address, app).serve_forever()


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO, format='%(levelname)s - - %(asctime)s %(message)s', datefmt='[%b %d %H:%M:%S]')
    if len(sys.argv) < 2:
        host, port = '127.0.0.1', 8080
    else:
        host, _, port = sys.argv[1].rpartition(':')
    logging.info('local python application serving at %s:%s', host, port)
    run_wsgi_app((host, int(port)), application)