def Resource(controller, faults=None, deserializers=None, serializers=None,action_status=None):"""Represents an API entity resource and the associated serialization anddeserialization logic"""default_deserializers = {'application/json': wsgi.JSONDeserializer()}default_serializers = {'application/json': wsgi.JSONDictSerializer()}format_types = {'json': 'application/json'}action_status = action_status or dict(create=201, delete=204)default_deserializers.update(deserializers or {})default_serializers.update(serializers or {})deserializers = default_deserializersserializers = default_serializersfaults = faults or {}@webob.dec.wsgify(RequestClass=Request)def resource(request):......# NOTE(blogan): this is something that is needed for the transition to# pecan.  This will allow the pecan code to have a handle on the controller# for an extension so it can reuse the code instead of forcing every# extension to rewrite the code for use with pecan.setattr(resource, 'controller', controller)setattr(resource, 'action_status', action_status)return resource

    @webob.dec.wsgify(RequestClass=Request)def resource(request):                                          # 处理Request的函数route_args = request.environ.get('wsgiorg.routing_args')if route_args:args = route_args[1].copy()else:args = {}# NOTE(jkoelker) by now the controller is already found, remove#                it from the args if it is in the matchdictargs.pop('controller', None)fmt = args.pop('format', None)action = args.pop('action', None)                                   # 获取请求中的format和action,移除controller。content_type = format_types.get(fmt,request.best_match_content_type())language = request.best_match_language()deserializer = deserializers.get(content_type)                      # 从deserializers中获取Content_type对应的deserializer。serializer = serializers.get(content_type)                          # 序列化同理。try:if request.body:args['body'] = deserializer.deserialize(request.body)['body']   # 将request中的body反序列化，e.g.str -> json。# Routes library is dumb and cuts off everything after last dot (.)# as format. At the same time, it doesn't enforce format suffix,# which combined makes it impossible to pass a 'id' with dots# included (the last section after the last dot is lost). This is# important for some API extensions like tags where the id is# really a tag name that can contain special characters.#
            # To work around the Routes behaviour, we will attach the suffix# back to id if it's not one of supported formats (atm json only).# This of course won't work for the corner case of a tag name that# actually ends with '.json', but there seems to be no better way# to tackle it without breaking API backwards compatibility.if fmt is not None and fmt not in format_types:args['id'] = '.'.join([args['id'], fmt])method = getattr(controller, action)                        # 从controller获取执行action的函数。result = method(request=request, **args)                    # 执行action，相关参数经反序列化后通过args参数传入controller。except Exception as e:mapped_exc = api_common.convert_exception_to_http_exc(e, faults,language)if hasattr(mapped_exc, 'code') and 400 <= mapped_exc.code < 500:LOG.info(_LI('%(action)s failed (client error): %(exc)s'),{'action': action, 'exc': mapped_exc})else:LOG.exception(_LE('%(action)s failed: %(details)s'),{'action': action,'details': utils.extract_exc_details(e),})raise mapped_excstatus = action_status.get(action, 200)body = serializer.serialize(result)                             # 将result序列化，e.g.json -> str。# NOTE(jkoelker) Comply with RFC2616 section 9.7if status == 204:content_type = ''body = Nonereturn webob.Response(request=request, status=status,           # 构造Response进行返回。content_type=content_type,body=body)