python - 如何在 Python 中使用 protobuf 映射？

Question

给定一个原型(prototype)定义

message EndpointResult {
    int32 endpoint_id = 1;
    // property id as key
    map<int32, TimeSeries> properties = 2;
}

message TimeSeries {
    repeated TimeEntry value = 2;
}

message TimeEntry {
    int32 time_unit = 1;
    float value = 2;
}

我希望在 EndpointResult 类中填充 map 。我尝试了 docs 中建议的不同方法但都对我提出了一个错误。

设置测试类

end_point_rslt = nom.EndpointResult()
end_point_rslt.endpoint_id=0

ts = nom.TimeSeries()
te = ts.value.add()
te.time_unit = 0
te.value = 5.

然后尝试不同的方法:

end_point_rslt.properties[0] = ts

ValueError: Direct assignment of submessage not allowed

end_point_rslt.properties[0].submessage_field = ts

AttributeError: Assignment not allowed (no field "submessage_field" in protocol message object).

end_point_rslt.properties.get_or_create(0)
end_point_rslt.properties[0] = ts

ValueError: Direct assignment of submessage not allowed

end_point_rslt.properties.get_or_create(0)
end_point_rslt.properties[0].submessage_field = ts

AttributeError: Assignment not allowed (no field "submessage_field" in protocol message object).

end_point_rslt.properties = {0 : ts}

AttributeError: Assignment not allowed to repeated field "properties" in protocol message object.

end_point_rslt.properties.get_or_create(0)
end_point_rslt.properties = {0 : ts}

TypeError: Can't set composite field

任何关于如何在 python 中使用 Protocol Buffer 映射的示例将不胜感激!

Answer 1

看了文档之后，我意识到问题出在我给字典分配了一个类。

正确的语法是

end_point_rslt = nom.EndpointResult()
end_point_rslt.endpoint_id=0
te = end_point_rslt.properties[0].value.add()
te.time_unit = 0
te.value = 5.