JSON Text Field Filter (django + django-filters)

field.py

class JSONTextFieldFilter(Filter):
    json_field_name = ""
    choices = {}

    def __init__(self, json_field_name=None, choices=None, **kwargs):
        self.choices = choices if choices else {}
        self.json_field_name = json_field_name if json_field_name else ""
        super().__init__(**kwargs)

    def modify_value(self, value):
        value = json.dumps({self.json_field_name: self.choices.get(value.lower(), value)})
        return value[1:-1]  # remove first '{' character and last - '}'

    def filter(self, qs, value):
        if isinstance(value, Lookup):
            lookup = six.text_type(value.lookup_type)
            value = value.value
        else:
            lookup = self.lookup_expr
        if value in EMPTY_VALUES:
            return qs

        value = self.modify_value(value)
        qs = self.get_method(qs)(**{'%s__%s' % (self.field_name, lookup): value})

        if self.distinct:
            qs = qs.distinct()

        return qs


class RelatedJSONTextFieldFilter(JSONTextFieldFilter):
    related_field_name = None

    def __init__(self, related_field_name=None, **kwargs):
        self.related_field_name = related_field_name
        super().__init__(**kwargs)

    def filter(self, qs, value):
        if isinstance(value, Lookup):
            lookup = six.text_type(value.lookup_type)
            value = value.value
        else:
            lookup = self.lookup_expr

        value = self.modify_value(value)

        qs = qs.prefetch_related(self.field_name).filter(
            **{'%s__%s__%s' % (self.field_name, self.related_field_name, lookup): value})

        if self.distinct:
            qs = qs.distinct()

        return qs