Quick startΒΆ
Suppose you have an xml document user.xml
:
<?xml version="1.0" encoding="utf-8"?>
<doc:envelope xmlns="http://www.test.org"
xmlns:doc="http://www.test1.org">
<doc:user name="Alex" surname="Ivanov" age="26">
<doc:birthdate year="1992" month="06" day="14"/>
<doc:contacts>
<doc:phone>+79204563539</doc:phone>
<doc:email>alex@gmail.com</doc:email>
<doc:email>alex@mail.ru</doc:email>
</doc:contacts>
<doc:documents>
<doc:passport series="3127" number="836815"/>
</doc:documents>
<data:occupations xmlns:data="http://www.test2.org">
<data:occupation title="yandex">
<data:address>Moscow</data:address>
<data:employees>8854</data:employees>
</data:occupation>
<data:occupation title="skbkontur">
<data:address>Yekaterinburg</data:address>
<data:employees>7742</data:employees>
</data:occupation>
</data:occupations>
</doc:user>
</doc:envelope>
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))
@property
def birthdate(self):
return date(year=self.birth_year, month=self.birth_month, day=self.birth_day)
@birthdate.setter
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')
@phone.validator
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:
try:
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}")
user.json
:
{
"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"
}