Methods

django-schemulator provides the following methods:

wtfield_to_schema(field)

This method takes a WTForms field and returns a JSON schema (a dictionary).

 

field_to_schema(field)

This method takes a Django Forms field and returns a JSON schema (a dictionary).

 

form_to_schema(form)

This method takes a Django Form or a WTForms and returns a JSON schema (a dictionary). Internally, it analyzes the fields that the form contains and uses one of the previous methods to provide the JSON schema representation.

Example

• Django Form

  class TestForm(forms.Form):
  
      boolean_field = forms.BooleanField(
                              label="Boolean Field",
                              help_text="This is a boolean field",
                              initial=True,
                              required=False)
  
      text_field = forms.CharField(
                              label="Text Field",
                              help_text="This is a text field",
                              required=False,
                              max_length=100,
                              min_length=20)text_field = text_field
  
      email_field = forms.EmailField( label="Email Field",
                              help_text="This is an email field",
                              initial="email@example.com",
                              max_length=100,
                              required=False)
  

• WTForm

  class TestForm(wtforms.Form):
  
      boolean_field = wtforms.BooleanField(
                              "Boolean Field",
                              description="This is a boolean field",
                              default=True,
                              validators=[wtforms.validators.Optional()])
  
      email_field = wtforms.StringField(
                             "Email Field",
                             description="This is an email field",
                             default="email@example.com",
                             validators=[ wtforms.validators.Email(),
                                          wtforms.validators.Length(max=100),)
                                          wtforms.validators.Optional()])
  
      text_field = wtforms.StringField(
                             "Text Field",
                             description="This is a text field",
                             validators=[ wtforms.validators.Length(min=20, max=100),
                                          wtforms.validators.Optional()])
  

For both forms, the corresponding JSON Shema is the following. Note: Some irrelevant entries have been removed for clarity.

{ '$schema': 'http://json-schema.org/draft-04/schema#', 
  'description': 'This is a JSON Schema describing a form',
  'title': 'JSON Schema'
  'properties': {
       'boolean_field': {
           'description': 'This is a boolean field', 
           'null': False, 
           'optional': True,
           'title': 'Boolean Field',
           'default': True,
           'type': 'boolean'}, 
       'email_field': {
           'description': 'This is an email field',
           'format': 'email',
           'maxLength': 100,
           'null': False, 
           'optional': True, 
           'title': 'Email Field',
           'default': 'email@example.com',
           'type': 'string'}, 
       'text_field': {
           'description': 'This is a text field',
           'minLength': 20,
           'maxLength': 100,
           'null': False,
           'optional': True,
           'title': 'Text Field',
           'default': None,
           'type': 'string'}},
}

 

schema_to_form(schema, form_type=None)

This method takes a dictionary with a valid JSON Schema syntax and returns a form. By default, the form returned is a Django Form, but by setting theform_type argument to wtforms the output is a WTForm.

 

schema_to_wtfield(schema)

This method is used by theschema_to_form() method to dynamically generate the fields within the returned form. It takes a dictionary with a valid JSON Schema syntax describing a field and returns an WTForms UnboundField instance.

If you where to use it independently, you may bind the field to a form by setting it as an attribute of a WTForms form before instatination, via setattr.

 

schema_to_field(schema)

This method is used by theschema_to_form() method to dynamically generate the fields within the returned form. It takes a dictionary with a valid JSON Schema syntax describing a field and returns an Django Forms field instance.

 

Special JSON Schema Keywords

django-schemulator recognizes three special keywords within a JSON Schema representation of a form. These can be provided to explicitly indicate which field classes and widgets should be used within the forms. These should be the name of the form or widget class.

• __django_form_field_cls

  The Django forms field class to be used.

• __wtforms_field_cls

  The WTForms field class to be used.

• __widget

  The Django forms or WTforms widget class to be used.

Example:

The following JSON Schema describes a Django forms CharField with a Textarea widget instead of the default TextInput widget.

{
'__django_form_field_cls': 'CharField', 
'__widget': 'Textarea',
'type': 'string',
'title': 'Text Area Field',
'description': 'This is a text area field',
'minLength': 0, 
'maxLength': 200,
'optional': False,
}