serpy

0.3.1 verified Fri May 01 auth: no python maintenance

serpy is a fast, simple object serialization library for Python, inspired by Django REST Framework (DRF) serializers but with a focus on speed. Current version is 0.3.1, released in 2018, with no recent updates. It supports Python 2.7 to 3.6 and has a low release cadence.

pip install serpy

Common errors

error AttributeError: module 'serpy' has no attribute 'Serializer' ↓

cause Importing only `import serpy` without the class.

fix

Use from serpy import Serializer or import serpy; serpy.Serializer.

error TypeError: __init__() got an unexpected keyword argument 'instance' ↓

cause Using keyword argument `obj` instead of `instance` (changed in 0.1.0).

fix

Use instance=... instead of obj=....

error KeyError: 'name' ↓

cause Serializing a dictionary missing a key with `required=True` (default).

fix

Use required=False on the field, or ensure the key exists.

Warnings

breaking Upgrading from 0.1.x to 0.2.0: If `required=False`, `None` values are now dropped from the output. Also, support for Python 2.6 is dropped. ↓

fix Review serializers that rely on `None` values being present; set `required=True` if you want `None` values included.

breaking In version 0.3.0, behavior for `required=True` and `required=False` changed to match DRF. Previously, `required=False` might have dropped `None` values; now `None` values are included. Missing keys cause `KeyError` for `required=True`. ↓

fix Adjust serializers relying on the old behavior: now `None` values are kept regardless of `required`, except when key is missing.

gotcha MethodField catches `AttributeError` and `KeyError` only if the method returns a value; if the method raises those errors for missing attributes, they are not caught and propagate. ↓

fix Ensure your `MethodField` method does not rely on catching these exceptions implicitly; handle them inside the method.

deprecated The library is no longer actively maintained; last release was 2018. No support for modern Python (3.7+), including f-strings, type hints, or asyncio. ↓

fix Consider using `marshmallow` or `pydantic` for ongoing support and modern Python.

Imports

Serializer
wrong
```
import serpy
```
correct
```
from serpy import Serializer
```
Importing `serpy` directly doesn't give you `Serializer`; you need to import the class explicitly.
IntField
wrong
```
from serpy.fields import IntField
```
correct
```
from serpy import IntField
```
Fields are not in a submodule; they are directly in `serpy`.

Quickstart

Define a serializer class and serialize a dictionary or object instance.

import serpy

class PersonSerializer(serpy.Serializer):
    name = serpy.StrField()
    age = serpy.IntField()

person = {'name': 'Alice', 'age': 30}
serializer = PersonSerializer(instance=person)
result = serializer.data
print(result)  # {'name': 'Alice', 'age': 30}