简单的 Nova REST API 实现程序

正在看Nova API的代码, 仿照其中的REST 实现写了一个程序. 

Nova API 当然支持了更多的功能, 例如XML/JSON序列化, 身份验证等等. 这个测试程序只实现其中的REST功能

MyRouter: 负责把HTTP请求, 根据匹配规则, 分发到不同的Application中

1) [ Python Deploy ] 收到HTTP请求后, 先调用 MyRouter的 __call__方法进行处理

2) [ MyRouter ] 根据内部的匹配定义, 通过RouteMiddleware 分发到对应的 MyApplication

MyApplication: 收到HTTP 请求后, 解析其中的参数信息, 调用后台的MyController业务类的对应方法

MyController: 最终的业务类, 接受参数, 执行业务逻辑的操作.

from __future__ import print_functionfrom routes import Mapperimport webob.decimport webob.excimport routes.middlewareimport testtoolsclass MyController(object):    def getlist(self, mykey):        print("step 4: MyController's getlist(self, mykey) is invoked")        return "getlist(), mykey=" + mykeyclass MyApplication(object):    """Test application to call from router."""    def __init__(self, controller):        self._controller = controller            def __call__(self, environ, start_response):        print("step 3: MyApplication is invoked")                action_args = environ['wsgiorg.routing_args'][1].copy()        try:            del action_args['controller']        except KeyError:            pass        try:            del action_args['format']        except KeyError:            pass                action = action_args.pop('action', None)        controller_method = getattr(self._controller, action)        result = controller_method(**action_args)                start_response('200 OK', [('Content-Type', 'text/plain')])        return [result]class MyRouter(object):    """Test router."""    def __init__(self):        route_name = "dummy_route"        route_path = "/dummies"                my_application = MyApplication(MyController())                 self.mapper = Mapper()        self.mapper.connect(route_name, route_path,                        controller=my_application,                        action="getlist",                        mykey="myvalue",                        conditions={"method": ['GET']})                        self._router = routes.middleware.RoutesMiddleware(self._dispatch,                                                          self.mapper)    @webob.dec.wsgify(RequestClass=webob.Request)    def __call__(self, req):        """Route the incoming request to a controller based on self.map.        If no match, return a 404.        """        print("step 1: MyRouter is invoked")        return self._router    @staticmethod    @webob.dec.wsgify(RequestClass=webob.Request)    def _dispatch(req):        """Dispatch the request to the appropriate controller.        Called by self._router after matching the incoming request to a route        and putting the information into req.environ.  Either returns 404        or the routed WSGI app's response.        """        print("step 2: RoutesMiddleware is invoked, calling our _dispatch back")                match_dict = req.environ['wsgiorg.routing_args'][1]        if not match_dict:            return webob.exc.HTTPNotFound()        app = match_dict['controller']        return app        class RoutingTestCase(testtools.TestCase):    def test_router(self):        router = MyRouter()        result = webob.Request.blank('/dummies').get_response(router)        self.assertEqual(result.body, "getlist(), mykey=myvalue")

从输出结果, 可以看出调用顺序是:  MyRouter --> routes.middleware.RoutesMiddleware --> MyApplication --> MyController:

[Test Case] test_routerstep 1: MyRouter is invokedstep 2: RoutesMiddleware is invoked, calling our _dispatch backstep 3: MyApplication is invokedstep 4: MyController's getlist(self, mykey) is invoked