Quick startΒΆ

Suppose you have an xml document user.xml:

<?xml version="1.0" encoding="utf-8"?>
<doc:envelope xmlns="http://www.test.org"
    <doc:user name="Alex" surname="Ivanov" age="26">

        <doc:birthdate year="1992" month="06" day="14"/>


            <doc:passport series="3127" number="836815"/>

        <data:occupations xmlns:data="http://www.test2.org">
            <data:occupation title="yandex">
            <data:occupation title="skbkontur">


To deserialize the document you could use xml python standard library api to parse the document and then set the corresponding class fields. Such an imperative code has a lot of boilerplate manipulations. Instead you can use paxb api to write declarative style code. All you need to describe field mappings and types, paxb will serialize and deserialize data for you:

import json
import re
from datetime import date

import attr
import paxb as pb

@pb.model(name='occupation', ns='data', ns_map={'data': 'http://www.test2.org'})
class Occupation:
    title = pb.attr()
    address = pb.field()
    employees = pb.field(converter=int)

@pb.model(name='user', ns='doc', ns_map={'doc': 'http://www.test1.org'})
class User:
    name = pb.attr()
    surname = pb.attr()
    age = pb.attr(converter=int)

    birth_year = pb.wrap('birthdate', pb.attr('year', converter=int))
    birth_month = pb.wrap('birthdate', pb.attr('month', converter=int))
    birth_day = pb.wrap('birthdate', pb.attr('day', converter=int))

    def birthdate(self):
        return date(year=self.birth_year, month=self.birth_month, day=self.birth_day)

    def birthdate(self, value):
        self.birth_year = value.year
        self.birth_month = value.month
        self.birth_day = value.day

    phone = pb.wrap('contacts', pb.field())
    emails = pb.wrap('contacts', pb.as_list(pb.field(name='email')))

    passport_series = pb.wrap('documents/passport', pb.attr('series'))
    passport_number = pb.wrap('documents/passport', pb.attr('number'))

    occupations = pb.wrap(
        'occupations', pb.lst(pb.nested(Occupation)), ns='data', ns_map={'data': 'http://www.test2.org'}

    citizenship = pb.field(default='RU')

    def check(self, attribute, value):
        if not re.match(r'\+\d{11,13}', value):
            raise ValueError("phone number is incorrect")

with open('user.xml') as file:
    xml = file.read()

Then the deserialized object can be modified and serialized back to xml document or converted to json format:

    user = pb.from_xml(User, xml, envelope='doc:envelope', ns_map={'doc': 'http://www.test1.org'})
    user.birthdate = user.birthdate.replace(year=1993)

    with open('user.json') as file:
        json.dump(attr.asdict(user), file)

except (pb.exc.DeserializationError, ValueError) as e:
    print(f"deserialization error: {e}")


    "age": 26,
    "birth_day": 14,
    "birth_month": 6,
    "birth_year": 1993,
    "citizenship": "RU",
    "emails": ["alex@gmail.com", "alex@mail.ru"],
    "name": "Alexey",
    "occupations": [
            "address": "Moscow",
            "employees": 8854,
            "title": "yandex"
            "address": "Yekaterinburg",
            "employees": 7742,
            "title": "skbkontur"
    "passport_number": "836815",
    "passport_series": "3127",
    "phone": "+79204563539",
    "surname": "Ivanov"