flask-inputfilter 0.0.6

A library to filter and validate input data inFlask applications

from src.flask_inputfilter.Validator import IsStringValidator

flask-inputfilter

The InputFilter class is used to validate and filter input data in Flask applications. It provides a modular way to clean and ensure that incoming data meets expected format and type requirements before being processed.

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Installation

pip install flask-inputfilter

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Quickstart

To use the InputFilter class, you need to create a new class that inherits from it and define the fields you want to validate and filter.

There are lots of different filters and validators available to use, but it is also possible to create your own.

Definition

from flask_inputfilter import InputFilter
from flask_inputfilter.Condition import ExactlyOneOfCondition
from flask_inputfilter.Enum import RegexEnum
from flask_inputfilter.Filter import StringTrimFilter, ToIntegerFilter, ToNullFilter
from flask_inputfilter.Validator import IsIntegerValidator, IsStringValidator, RegexValidator


class UpdateZipcodeInputFilter(InputFilter):
    def __init__(self):

        super().__init__()

        self.add(
            'id',
            required=True,
            filters=[ToNullFilter()],
            validators=[
                IsIntegerValidator()
            ]
        )

        self.add(
            'zipcode',
            filters=[StringTrimFilter()],
            validators=[
                RegexValidator(
                    RegexEnum.POSTAL_CODE.value,
                    'The zipcode is not in the correct format.'
                )
            ]
        )

        self.add(
            'city',
            filters=[StringTrimFilter()],
            validators=[
                IsStringValidator()
            ]
        )

        self.addCondition(
            ExactlyOneOfCondition(['zipcode', 'city'])
        )

Usage

To use the InputFilter class, you need to call the validate method on the class instance. After calling the validate method, the validated data will be available in the g.validatedData object in the wanted format. If the data is not valid, the validate method will return a 400 response with the error message.

from flask import Flask, g
from your-path import UpdateZipcodeInputFilter

app = Flask(__name__)

@app.route('/update-zipcode', methods=['POST'])
@UpdateZipcodeInputFilter.validate()
def updateZipcode():
    data = g.validatedData

    # Do something with validatedData
    id = data.get('id')
    zipcode = data.get('zipcode')

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Options

The add method takes the following options:

• Required
• Filter
• Validator
• Default
• Fallback
• ExternalApi

Required

The required option is used to specify if the field is required or not. If the field is required and not present in the input data, the validate method will return the ValidationError with an error message.

Default

The default option is used to specify a default value to use if the field is not present in the input data.

Fallback

The fallback option is used to specify a fallback value to use if something unexpected happens, for example if the field is required but no value where provides or the validation fails.

This means that if the field is not required and no value is present, the fallback value will not be used. In this case you have to use the default option.