循环遍历Python中的Protocol Buffers属性

Question

我想帮助递归循环遍历协议缓冲区消息中包含的所有属性/子对象,假设我们不知道它们的名称,或者有多少.

例如,从google网站上的教程中获取以下.proto文件:

  message Person {
    required string name = 1;
    required int32 id = 2;
    optional string email = 3;

  enum PhoneType {
    MOBILE = 0;
    HOME = 1;
    WORK = 2;
  }

  message PhoneNumber {
    required string number = 1;
    optional PhoneType type = 2 [default = HOME];
  }

  repeated PhoneNumber phone = 4;
}

并使用它...:

person = tutorial.Person()
person.id = 1234
person.name = "John Doe"
person.email = "jdoe@example.com"
phone = person.phone.add()
phone.number = "555-4321"
phone.type = tutorial.Person.HOME

鉴于Person,我怎么那么对每个元素访问属性的名称和它的值:person.id,person.name,person.email,person.phone.number,person.phone.type？

我已经尝试了以下内容,但它似乎没有重复进入person.phone.number或person.phone.type.

object_of_interest = Person

while( hasattr(object_of_interest, "_fields") ):
  for obj in object_of_interest._fields:
    # Do_something_with_object(obj) # eg print obj.name
    object_of_interest = obj

我尝试使用obj.DESCRIPTOR.fields_by_name.keys访问子元素,但这些是子对象的字符串表示,而不是对象本身.

obj.name给了我名字的属性,但我不知道如何实际获得该属性的值,例如obj.name可能会给我'名字',但我如何得到'john doe'呢？

Answer 1

我对protobufs并不是很熟悉,所以对于这种事情可能有一种更简单的方法或api.但是,下面显示了如何迭代/内省和对象字段并将其打印出来的示例.希望足以让你至少朝着正确的方向前进......

import addressbook_pb2 as addressbook

person = addressbook.Person(id=1234, name="John Doe", email="foo@example.com")
person.phone.add(number="1234567890")


def dump_object(obj):
    for descriptor in obj.DESCRIPTOR.fields:
        value = getattr(obj, descriptor.name)
        if descriptor.type == descriptor.TYPE_MESSAGE:
            if descriptor.label == descriptor.LABEL_REPEATED:
                map(dump_object, value)
            else:
                dump_object(value)
        elif descriptor.type == descriptor.TYPE_ENUM:
            enum_name = descriptor.enum_type.values[value].name
            print "%s: %s" % (descriptor.full_name, enum_name)
        else:
            print "%s: %s" % (descriptor.full_name, value)

dump_object(person)

哪个输出

tutorial.Person.name: John Doe
tutorial.Person.id: 1234
tutorial.Person.email: foo@example.com
tutorial.Person.PhoneNumber.number: 1234567890
tutorial.Person.PhoneNumber.type: HOME