sqlalchemy.orm.util identity_key Example Code

# fields.py
from __future__ import unicode_literals

import operator
from itertools import groupby

import six
from sqlalchemy.orm.util import identity_key
from sqlalchemy_utils import Country, i18n, PhoneNumber
from sqlalchemy_utils.primitives import WeekDay, WeekDays
from wtforms import widgets
from wtforms.compat import string_types, text_type
from wtforms.fields import FieldList, FormField, SelectFieldBase
from wtforms.validators import ValidationError
from wtforms.widgets import CheckboxInput, ListWidget
from wtforms_components import SelectField, SelectMultipleField
from wtforms_components.fields.html5 import StringField
from wtforms_components.widgets import SelectWidget, TelInput

from .utils import find_entity

try:
    from wtforms.utils import unset_value as _unset_value
except ImportError:
    from wtforms.fields import _unset_value


class SkipOperation(Exception):
    pass


class ModelFormField(FormField):


## ... source file abbreviated to get to identity_key examples ...



    def _set_data(self, data):
        self._data = data
        self._formdata = None

    data = property(_get_data, _set_data)

    def iter_choices(self):
        for pk, obj in self._get_object_list():
            yield (pk, self.get_label(obj), obj in self.data)

    def process_formdata(self, valuelist):
        self._formdata = set(valuelist)

    def pre_validate(self, form):
        if self._invalid_formdata:
            raise ValidationError(self.gettext('Not a valid choice'))
        elif self.data:
            obj_list = list(x[1] for x in self._get_object_list())
            for v in self.data:
                if v not in obj_list:
                    raise ValidationError(self.gettext('Not a valid choice'))


def get_pk_from_identity(obj):
    cls, key = identity_key(instance=obj)[0:2]
    return ':'.join(text_type(x) for x in key)


class GroupedQuerySelectField(SelectField):
    widget = SelectWidget()

    def __init__(
        self,
        label=None,
        validators=None,
        query_factory=None,
        get_pk=None,
        get_label=None,
        get_group=None,
        allow_blank=False,
        blank_text='',
        blank_value='__None',
        **kwargs
    ):
        super(GroupedQuerySelectField, self).__init__(
            label,
            validators,
            coerce=lambda x: x,
            **kwargs


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