OcataNeutron代码分析（六）——APIRouter的初始化（3）顶级resource的map过程

def Resource(controller, faults&＃61;None, deserializers&＃61;None, serializers&＃61;None,action_status&＃61;None):"""Represents an API entity resource and the associated serialization anddeserialization logic"""default_deserializers &＃61; {&＃39;application/json&＃39;: wsgi.JSONDeserializer()}default_serializers &＃61; {&＃39;application/json&＃39;: wsgi.JSONDictSerializer()}format_types &＃61; {&＃39;json&＃39;: &＃39;application/json&＃39;}action_status &＃61; action_status or dict(create&＃61;201, delete&＃61;204)default_deserializers.update(deserializers or {})default_serializers.update(serializers or {})deserializers &＃61; default_deserializersserializers &＃61; default_serializersfaults &＃61; faults or {}&＃64;webob.dec.wsgify(RequestClass&＃61;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, &＃39;controller&＃39;, controller)setattr(resource, &＃39;action_status&＃39;, action_status)return resource

&＃64;webob.dec.wsgify(RequestClass&＃61;Request)def resource(request): # 处理Request的函数route_args &＃61; request.environ.get(&＃39;wsgiorg.routing_args&＃39;)if route_args:args &＃61; route_args[1].copy()else:args &＃61; {}# NOTE(jkoelker) by now the controller is already found, remove# it from the args if it is in the matchdictargs.pop(&＃39;controller&＃39;, None)fmt &＃61; args.pop(&＃39;format&＃39;, None)action &＃61; args.pop(&＃39;action&＃39;, None) # 获取请求中的format和action,移除controller。content_type &＃61; format_types.get(fmt,request.best_match_content_type())language &＃61; request.best_match_language()deserializer &＃61; deserializers.get(content_type) # 从deserializers中获取Content_type对应的deserializer。serializer &＃61; serializers.get(content_type) # 序列化同理。try:if request.body:args[&＃39;body&＃39;] &＃61; deserializer.deserialize(request.body)[&＃39;body&＃39;] # 将request中的body反序列化&＃xff0c;e.g.str -> json。# Routes library is dumb and cuts off everything after last dot (.)# as format. At the same time, it doesn&＃39;t enforce format suffix,# which combined makes it impossible to pass a &＃39;id&＃39; 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&＃39;s not one of supported formats (atm json only).# This of course won&＃39;t work for the corner case of a tag name that# actually ends with &＃39;.json&＃39;, 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[&＃39;id&＃39;] &＃61; &＃39;.&＃39;.join([args[&＃39;id&＃39;], fmt])method &＃61; getattr(controller, action) # 从controller获取执行action的函数。result &＃61; method(request&＃61;request, **args) # 执行action&＃xff0c;相关参数经反序列化后通过args参数传入controller。except Exception as e:mapped_exc &＃61; api_common.convert_exception_to_http_exc(e, faults,language)if hasattr(mapped_exc, &＃39;code&＃39;) and 400 <&＃61; mapped_exc.code <500:LOG.info(_LI(&＃39;%(action)s failed (client error): %(exc)s&＃39;),{&＃39;action&＃39;: action, &＃39;exc&＃39;: mapped_exc})else:LOG.exception(_LE(&＃39;%(action)s failed: %(details)s&＃39;),{&＃39;action&＃39;: action,&＃39;details&＃39;: utils.extract_exc_details(e),})raise mapped_excstatus &＃61; action_status.get(action, 200)body &＃61; serializer.serialize(result) # 将result序列化&＃xff0c;e.g.json -> str。# NOTE(jkoelker) Comply with RFC2616 section 9.7if status &＃61;&＃61; 204:content_type &＃61; &＃39;&＃39;body &＃61; Nonereturn webob.Response(request&＃61;request, status&＃61;status, # 构造Response进行返回。content_type&＃61;content_type,body&＃61;body)