仿Openstack的WSGI接口及RESTul服务实现（python）

34rfdw

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()

然后是testroutes.ini文件
 

[DEFAULT]
name=huang
[composite:main]
use=egg:Paste#urlmap
/=show
[pipeline:show]
pipeline = root
[app:root]
paste.app_factory = testroutes:Router.app_factory
由此可见，ini文件按照pastedeploy的模式配置了根目录/，指向pipeline show，pipeline又指向app root。app下指向的是Router的app_factory函数，返回的是Router().根据调用过程，初始化__init__->__call__返回self._routers.根据__init__下写的映射规则，能识别类似/test/123这样的路径，其处理函数调用"Controller"的"action"函数，也就是getMessage。
 
测试运行，在浏览器下输入127.0.0,1:8282/test/123
返回OK,如
 

return webob.Response('OK')
 
测试完毕。
 
bluefire1991
2013.11.2
19:59:12