xml-to-pydantic 0.1

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xml-to-pydantic

xml-to-pydantic is a library for Python to convert XML to pydantic models.

(Please note that this project is not affiliated in any way with the great team at pydantic.)

pydantic is a Python library for data validation, applying type hints / annotations. It enables the creation of easy or complex data validation rules for processing external data. That data usually comes in JSON format or from a Python dictionary.

But to process and validate XML into pydantic models would then require two steps: convert the XML to a Python dictionary, then convert to the pydantic model. This libary provides a convenient way to combine those steps.

Note: if you are using this library to parse external, uncontrolled XML, you should be aware of possible attack vectors through XML: [https://github.com/tiran/defusedxml]. This library uses lxml under the hood.

Installation

Use pip, or your favorite Python package manager (pipenv, poetry, pdm, ...):

pip install xml-to-pydantic

Usage

The XML is extracted using XPath defined on the fields:

from xml_to_pydantic import XmlBaseModel, XmlField


xml_bytes = b"""<?xml version="1.0" encoding="UTF-8"?>
<root>
    <element>4.53</element>
    <a href="https://example.com">Link</a>
</root>
"""


class MyModel(XmlBaseModel):
    number: float = XmlField(xpath="./element/text()")
    href: str = XmlField(xpath="./a/@href")


model = MyModel.model_validate_xml(xml_bytes)
print(model)
# > number=4.53 href='https://example.com'

The parsing can also deal with nested models and lists:

from xml_to_pydantic import XmlBaseModel, XmlField


xml_bytes = b"""<?xml version="1.0" encoding="UTF-8"?>
<root>
    <level1>
        <level2>value1</level2>
        <level2>value2</level2>
        <level2>value3</level2>
    </level1>
    <level11>value11</level11>
</root>
"""

class NextLevel(XmlBaseModel):
    level2: list[str] = XmlField(xpath="./level2/text()")


class MyModel(XmlBaseModel):
    next_level: NextLevel = XmlField(xpath="./level1")
    level_11: list[str] = XmlField(xpath="./level11/text()")


model = MyModel.model_validate_xml(xml_bytes)
print(model)
# > next_level=NextLevel(level2=['value1', 'value2', 'value3']) level_11=['value11']

Development

Prerequisites:

• Any Python 3.8 through 3.12
• poetry for dependency management
• git
• make (to use the helper scripts in the Makefile)

Autoformatting can be applied by running

make lintable

Before commiting, remember to run

make lint
make test