Extract auth token from stream and check authorization from WatchDocument

[hackerwins]

Description:

Extracting auth token from streams.

yorkie/yorkie/rpc/interceptors/auth.go

Lines 62 to 73 in 6eccd48

	// Stream creates a stream server interceptor for authorization.
	func (i *AuthInterceptor) Stream() grpc.StreamServerInterceptor {
	return func(
	srv interface{},
	ss grpc.ServerStream,
	info *grpc.StreamServerInfo,
	handler grpc.StreamHandler,
	) error {
	// TODO(hackerwins): extract token and store it on the context.
	return handler(srv, ss)
	}
	}

We can use grpc_middleware.WrapServerStream to handle it.

https://github.com/grpc-ecosystem/go-grpc-middleware/blob/93b7816b469d4889200df9121cbe799678bce1bf/auth/auth.go#L51-L67

Why:

Authorization is missing from WatchDocument.