Deserialization

Deserialization in Flask-InputFilter allows you to convert validated data into custom model objects or maintain it as a dictionary. This feature is particularly useful when you want to work with strongly-typed objects in your application.

Overview

The deserialization process is handled through two main methods:

• set_model(): Sets the model class to be used for deserialization

• serialize(): Converts the validated data into an instance of the specified model class or returns the raw data as a dictionary

Configuration

The validate() method will automatically deserialize the validated data into an instance of the model class, if there is a model class set.

from dataclasses import dataclass


@dataclass
class User:
    username: str
    email: str


class UserInputFilter(InputFilter):
    def __init__(self):
        super().__init__()

        self.set_model(User)

Examples

Usage with Flask Routes

You can also use deserialization in your Flask routes:

from flask import Flask, jsonify, g


class User:
    def __init__(self, username: str):
        self.username = username


class MyInputFilter(InputFilter):
    def __init__(self):
        super().__init__(methods=["GET"])
        self.add("username")
        self.set_model(User)


app = Flask(__name__)

@app.route("/test", methods=["GET"])
@MyInputFilter.validate()
def test_route():
    # g.validated_data will contain the deserialized User instance

    validated_data: User = g.validated_data

Usage outside of Flask Routes

You can also use deserialization outside of Flask routes:

from flask import Flask, jsonify, g


class User:
    def __init__(self, username: str):
        self.username = username


class MyInputFilter(InputFilter):
    def __init__(self):
        super().__init__(methods=["GET"])
        self.add("username")
        self.set_model(User)

app = Flask(__name__)

@app.route("/test", methods=["GET"])
def test_route():
    input_filter = MyInputFilter()
    input_filter.set_data({"username": "test user"})

    if not input_filter.is_valid():
        return jsonify({"error": "Invalid data"}), 400

    validated_data: User = input_filter.serialize()