Introduction

django-jschemer converts Django Forms into JSON Schema compatibile representations.

Originally a fork of https://github.com/zbyte64/django-jsonschema but it turned into a major rewrite.

Requirements

• Python 3 or later (not tested with 2.x)
• Django 1.8 or later, althought it should probably work in earlier versions

Usage

Add app to Django installed apps.:

INSTALLED_APPS =  [
        # Other apps
        'django_jschemer',
        ]

To convert a form to a JSON Schema:

from django_jschemer.jsonschema import DjangoFormToJSONSchema

schema_repr , alpaca_options = DjangoFormToJSONSchema().convert_form(MyForm)

If you have written your own custom Fields (django.forms.field.Field subclasses) then it is easy to add them to django-jschemer using a method just like Django's admin registry:

You need to subclass django_schemer.fields.BaseDjangoJSONSchemaField and provide relevant method overrides.

overriding def_type() is required but everything else is optional. get_type should return a string with the JSON Schema 'type' field.

Example:

class CustomSchemaField(BaseDjangoJSONSchemaField):

    def get_type(self):
        return "string"

    # optionally define a get_format() method
    def get_format(self):
        return "email"

There are now 2 ways to add this to the registry.

Method 1:

from django_jschemer.registry import registry
registry.register(YourCustomField,CustomSchemaField)

Method 2 (decorator):

from django_jschemer.decorators import register as schema_register

@schema_register(CustomSchemaField)
class MyCustomField(Field):
    # you field code here
    pass

To embed a JSON Schema as a form field:

from django_jschemer.forms import JSONSchemaField

#where schema is a python dictionay like schema_repr in the first exmaple

class MyForm(forms.Form):
    subfield = JSONSchemaField(schema=schema)

form = MyForm(data={'subfield':'<json encoded value>'})
form.validate() #will validate the subfield entry against schema
form['subfield'].as_widget() #will render a textarea widget with a data-schemajson attribute

You also have the choice of adding options to schema and or alpaca options with an inner class inside your Form:

from django import forms

class MyForm(forms.Form):
    COLORS = (
    ('red','Awesome Red'),
    ('blue','Sky Blue'),
    )
    paper = forms.CharField(max_length=30)
    paper_color = forms.ChoiceField(choices=COLORS)

    class SchemerOptions:
        # options is a dictionary that is used to update() alpaca options.
        # It will override any option calculated to django-jschemer
        options = {
            'fields':{
                'paper':{'placeholder':'Placeholder text'},
            }
        }

        # schema is a dictionary that is used to update() JSON Schema
        # It will override any option calculated to django-jschemer
        schema = {
            'dependencies':{
                'paper_color':['paper'],
            }
        }

Static files

django-jschemer comes with some default Javascript to initialize AlpacaJS. It does NOT include alpacajs or handlebars or jQuery which is left up to you to do.

The default JS file requires jQuery. IT is fairly trivial to replace it with your own as per the Django static files override rules.