仿Openstack的WSGI接口及RESTul服务实现是怎样的

Openstack的WSGI接口通过webob,pastedeploy,routes实现了Controller类，和Router类，这里仿照Openstack的WSG接口实现简单的测试程序

首先是testroutes.py文件

import logging
import os

import webob.dec  
import webob.exc
from paste.deploy import loadapp
from wsgiref.simple_server import make_server  

import routes.middleware  
# Environment variable used to pass the request context
CONTEXT_ENV = 'openstack.context'


# Environment variable used to pass the request params
PARAMS_ENV = 'openstack.params'

LOG = logging.getLogger(__name__)

class Controller(object): 
    @webob.dec.wsgify
    def __call__(self, req):
        arg_dict = req.environ['wsgiorg.routing_args'][1]
        action = arg_dict.pop('action')
        del arg_dict['controller']
        context = req.environ.get(CONTEXT_ENV, {})
        context['query_string'] = dict(req.params.iteritems())
        context['headers'] = dict(req.headers.iteritems())
        context['path'] = req.environ['PATH_INFO']
        params = req.environ.get(PARAMS_ENV, {})

        for name in ['REMOTE_USER', 'AUTH_TYPE']:
            try:
                context[name] = req.environ[name]
            except KeyError:
                try:
                    del context[name]
                except KeyError:
                    pass

        params.update(arg_dict)

        # TODO(termie): do some basic normalization on methods
        method = getattr(self, action)

        
        result = method(context, **params)
        
        return webob.Response('OK')
    
    def getMessage(self,context, user_id):
        return {'Message': 'TestMessage'}
        pass
        
class Router(object):  
    def __init__(self):  
        self._mapper = routes.Mapper()  
        self._mapper.connect('/test/{user_id}',
                            controller=Controller(),
                            action='getMessage',
                            conditions={'method': ['GET']})
        
        self._router = routes.middleware.RoutesMiddleware(self._dispatch, self._mapper)
     
    @webob.dec.wsgify  
    def __call__(self, req):
        return self._router
    
    @staticmethod  
    @webob.dec.wsgify  
    def _dispatch(req):
        match = req.environ['wsgiorg.routing_args'][1]  
                      
        if not match:  
            return webob.exc.HTTPNotFound()  
              
        app = match['controller']
        return app
    
    @classmethod
    def app_factory(cls, global_config, **local_config):    
        return cls()
        

if __name__ == '__main__':
    configfile='testroutes.ini'
    appname="main"
    wsgi_app = loadapp("config:%s" % os.path.abspath(configfile), appname)  
    httpd = make_server('localhost', 8282, wsgi_app)  
    httpd.serve_forever()

[DEFAULT]
name=huang

[composite:main]
use=egg:Paste#urlmap
/=show

[pipeline:show]
pipeline = root

[app:root]
paste.app_factory = testroutes:Router.app_factory

return webob.Response('OK')