django-multiselectfield/src/multiselectfield/db/fields.py

# -*- coding: utf-8 -*-
# Copyright (c) 2012-2013 by Pablo Martín <goinnn@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this programe.  If not, see <http://www.gnu.org/licenses/>.


import sys

from django.db import models
from django.utils.text import capfirst
from django.core import exceptions

from ..forms.fields import MultiSelectFormField

if sys.version_info[0] == 2:
    string = basestring
    string_type = unicode
else:
    string = str
    string_type = string

# Code from six egg https://bitbucket.org/gutworth/six/src/a3641cb211cc360848f1e2dd92e9ae6cd1de55dd/six.py?at=default


def add_metaclass(metaclass):
    """Class decorator for creating a class with a metaclass."""
    def wrapper(cls):
        orig_vars = cls.__dict__.copy()
        orig_vars.pop('__dict__', None)
        orig_vars.pop('__weakref__', None)
        for slots_var in orig_vars.get('__slots__', ()):
            orig_vars.pop(slots_var)
        return metaclass(cls.__name__, cls.__bases__, orig_vars)
    return wrapper


class MultiSelectField(models.CharField):
    """ Choice values can not contain commas. """

    def get_choices_default(self):
        return self.get_choices(include_blank=False)

    def get_choices_selected(self, arr_choices=''):
        if not arr_choices:
            return False
        list = []
        for choice_selected in arr_choices:
            list.append(string_type(choice_selected[0]))
        return list

    def _get_FIELD_display(self, field):
        value = getattr(self, field.attname)
        choicedict = dict(field.choices)

    def value_to_string(self, obj):
        value = self._get_val_from_obj(obj)
        return self.get_prep_value(value)

    def validate(self, value, model_instance):
        arr_choices = self.get_choices_selected(self.get_choices_default())
        for opt_select in value:
            if (opt_select not in arr_choices):
                raise exceptions.ValidationError(self.error_messages['invalid_choice'] % value)
        return

    def formfield(self, **kwargs):
        defaults = {'required': not self.blank, 'label': capfirst(self.verbose_name),
                    'help_text': self.help_text, 'choices': self.choices}
        if self.has_default():
            defaults['initial'] = self.get_default()
        defaults.update(kwargs)
        return MultiSelectFormField(**defaults)

    def get_prep_value(self, value):
        if isinstance(value, string):
            return value
        elif isinstance(value, list):
            return ",".join(value)

    def to_python(self, value):
        if value is not None:
            return value if isinstance(value, list) else value.split(',')
        return ''

    def contribute_to_class(self, cls, name):
        super(MultiSelectField, self).contribute_to_class(cls, name)
        if self.choices:
            func = lambda self, fieldname = name, choicedict = dict(self.choices): ",".join([string_type(choicedict.get(value, value)) for value in getattr(self, fieldname)])
            setattr(cls, 'get_%s_display' % self.name, func)


MultiSelectField = add_metaclass(models.SubfieldBase)(MultiSelectField)

try:
    from south.modelsinspector import add_introspection_rules
    add_introspection_rules([], ['^multiselectfield\.db.fields\.MultiSelectField'])
except ImportError:
    pass