Python Dataclass Serializer


Recently, I've found myself doing a lot of work in Flask. Because of this, I've had to devise a way to serialize/map dictionaries to dataclasses. This is what I've come up with.


Let's start out with a basic data class.

from dataclasses import dataclass
from datetime import datetime
from decimal import Decimal
from uuid import UUID

class Watch:
    id         : UUID                 = None
    tag        : str                  = None
    symbol     : str                  = None
    price      : Decimal              = None
    email      : str                  = None
    created_on : datetime             =
    closed_on  : datetime             = None


Here is the base serializer class that all future serializers should inherit from:

# Base serializer class
class SerializerBase:
    DomainModel: dataclass = object

    # Constructor
    # Args:
    #   - dictionary: a dict of the data to serialize into the Domain Model
    #   - domain_model: an instance of the class' DomainModel or None
    def __init__(self, dictionary: dict, domain_model = None):
        self.dictionary = dictionary
        # if the given domain_model is not null, set the object's domain_model field to it
        # otherwise, call the contructor of the class' DomainModel
        self.domain_model = domain_model or self.DomainModel()

    # Serialize the object's dictionary into the sub-class' domain model
    def serialize(self) -> dataclass:
        model = self.domain_model

        # get a list of all the Model's attributes
        model_keys = list(model.__annotations__.keys())

        # if the dict's key is an attribute in the model, copy over the value
        for key, value in self.dictionary.items():
            if not key in model_keys:
            elif not value:
                setattr(model, key, None)
                setattr(model, key, value or None)

        return model

Now, let's make one more class that will inherit the BaseSerializer class and serialize a dictionary into a Watch object:

import models

class WatchSerializer(SerializerBase):
    DomainModel = models.Watch

If you want to do some additional work on the object before returning it:

import models
from datetime import datetime

class WatchSerializer(SerializerBase):
    DomainModel = models.Watch

    def serialize(self) -> models.Watch:
        model = super().serialize()

        if model.closed_on == None:
            model.closed_on =

        return model


Now, to use the WatchSerializer class:

from serializers import WatchSerializer
from models import Watch

d = dict(
    tag = 'tag value',
    symbol = 'symbol',
    price = 44.24,
    email = ',
    closed_on = None,

serializer = WatchSerializer(d)
watch = serializer.serialize()

© 2023 by Ryan Rickgauer