在 capnproto RPC 中识别调用者

identifying caller in capnproto RPC

我正在 CapnProto 中实现一项服务。该服务遵循以下步骤(大致):

  1. 在服务器上验证
  2. 一旦验证通过服务接口(对象能力)进行操作。

我想实现如下目标:

interface Authorization {
   login @0 (userName :User) -> (result :Service);
}

interface Service {
   # doOperation needs userName in order to operate, as an implicit
   # parameter, when the RPC arrives. I do not want to use an explicit 
   # userName parameter. Otherwise, a user could claim to
   # be someone else in a function parameter. To achieve this I need
   # to know who is the userName that holds this capability from inside
   # doOperation. I want to avoid token authentication 
   # for each operation.
   # Thus, the RPC I am implementing is stateful.
   doOperation @0 (param1 :A); 
   #...
}

我想要的是,从 doOperation 中,我可以识别正在使用该功能的用户(我想知道她的用户名)。即:

原来这个很简单

在代码中创建Service接口时,只需将认证信息传递并保存在Service对象中即可,如下所示:

class ServiceImpl : public Service::Server {
   string userId_;
public:
   explicit ServiceImpl(string userId) : userId_(move(userId)) {}
protected:
   kj::Promise<void> doOperatoration(DoOperationContext ctx) override {
        //use userId_ here

   }
};

class AuthorizationImpl : public Authorization::Server {
protected:
   kj::Promise<void> login(LoginContext ctx) override {
       std::string user = ctx.getParams().getUserName();
       //Here I forward the authentication state to the service
       ctx.getResults().setService(kj::heap<ServiceImpl>(user);     
       //..
   }
};