JsonForm

Form validation for JSON-like data (i.e. document) in Python.

Introduction

JsonForm is mainly based on jsonschema, which is an implementation of JSON Schema for Python.

Unlike the other validation libraries in Python, JsonForm is dedicated to validating JSON-like data, which means it's a document-oriented validation library.

Validation Rules

All possible validation keywords supported by JsonForm is in JSON Schema style.

As an example, the type keyword is fundamental to JSON Schema. It specifies the data type for a schema. The following table maps from the names of JavaScript types to their analogous types in Python:

For more keywords, see JSON Schema Validation.

Getting Started

Basic example

from jsonform import JsonForm

class ProductForm(JsonForm):
    schema = {
        'type': 'object',
        'properties': {
            'name': {'type': 'string'},
            'price': {'type': 'number'},
        },
    }

>>> # Valid document
>>> form = ProductForm({'name': 'Eggs', 'price': 34.99})
>>> if not form.is_valid():
...     print(form.errors)
...

>>> # Invalid document
>>> form = ProductForm({'name': 'Eggs', 'price': 'Invalid'})
>>> if not form.is_valid():
...     print(form.errors)
...
{'price': "'Invalid' is not of type 'number'"}

Customizing messages

from jsonform import JsonForm

class ProductForm(JsonForm):
    schema = {
        'type': 'object',
        'properties': {
            'name': {'type': 'string'},
            'price': {'type': 'number'},
        },
    }
    messages = {
        'properties.price.type': "Hey, it's not ok..."
    }

>>> form = ProductForm({'name': 'Eggs', 'price': 'Invalid'})
>>> if not form.is_valid():
...     print(form.errors)
...
{'price': "Hey, it's not ok..."}

Partial validation

from jsonform import JsonForm

class ProductForm(JsonForm):
    schema = {
        'type': 'object',
        'properties': {
            'name': {'type': 'string'},
            'price': {'type': 'number'},
        },
        'required': ['name'],
    }

>>> # Normal validation
>>> form = ProductForm({'price': 'Invalid'})
>>> if not form.is_valid():
...     print(form.errors)
...
{'price': "'Invalid' is not of type 'number'", 'name': "'name' is a required property"}

>>> # Partial validation
>>> form = ProductForm({'price': 'Invalid'}, partial=True)
>>> if not form.is_valid():
...     print(form.errors)
...
{'price': "'Invalid' is not of type 'number'"}

Customizing validator

from jsonform import JsonForm

class ProductForm(JsonForm):
    def validate_name(value):
        if not value.istitle():
            return 'name must be title'

    schema = {
        'type': 'object',
        'properties': {
            'name': {'custom': validate_name}
            'price': {'type': 'number'},
        },
    }

>>> form = ProductForm({'name': 'eggs', 'price': 34.99})
>>> if not form.is_valid():
...     print(form.errors)
...
{'name': 'name must be title'}