Skip to content
This repository

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
file 1203 lines (1029 sloc) 46.816 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
"""
Field classes.
"""

from __future__ import unicode_literals

import copy
import datetime
import os
import re
import sys
import warnings
from decimal import Decimal, DecimalException
from io import BytesIO

from django.core import validators
from django.core.exceptions import ValidationError
from django.forms.utils import from_current_timezone, to_current_timezone
from django.forms.widgets import (
    TextInput, NumberInput, EmailInput, URLInput, HiddenInput,
    MultipleHiddenInput, ClearableFileInput, CheckboxInput, Select,
    NullBooleanSelect, SelectMultiple, DateInput, DateTimeInput, TimeInput,
    SplitDateTimeWidget, SplitHiddenDateTimeWidget, FILE_INPUT_CONTRADICTION
)
from django.utils import formats
from django.utils.encoding import smart_text, force_str, force_text
from django.utils.ipv6 import clean_ipv6_address
from django.utils.deprecation import RemovedInDjango19Warning
from django.utils import six
from django.utils.six.moves.urllib.parse import urlsplit, urlunsplit
from django.utils.translation import ugettext_lazy as _, ungettext_lazy

# Provide this import for backwards compatibility.
from django.core.validators import EMPTY_VALUES # NOQA


__all__ = (
    'Field', 'CharField', 'IntegerField',
    'DateField', 'TimeField', 'DateTimeField',
    'RegexField', 'EmailField', 'FileField', 'ImageField', 'URLField',
    'BooleanField', 'NullBooleanField', 'ChoiceField', 'MultipleChoiceField',
    'ComboField', 'MultiValueField', 'FloatField', 'DecimalField',
    'SplitDateTimeField', 'IPAddressField', 'GenericIPAddressField', 'FilePathField',
    'SlugField', 'TypedChoiceField', 'TypedMultipleChoiceField'
)


class Field(object):
    widget = TextInput # Default widget to use when rendering this type of Field.
    hidden_widget = HiddenInput # Default widget to use when rendering this as "hidden".
    default_validators = [] # Default set of validators
    # Add an 'invalid' entry to default_error_message if you want a specific
    # field error message not raised by the field validators.
    default_error_messages = {
        'required': _('This field is required.'),
    }
    empty_values = list(validators.EMPTY_VALUES)

    # Tracks each time a Field instance is created. Used to retain order.
    creation_counter = 0

    def __init__(self, required=True, widget=None, label=None, initial=None,
                 help_text='', error_messages=None, show_hidden_initial=False,
                 validators=[], localize=False):
        # required -- Boolean that specifies whether the field is required.
        # True by default.
        # widget -- A Widget class, or instance of a Widget class, that should
        # be used for this Field when displaying it. Each Field has a
        # default Widget that it'll use if you don't specify this. In
        # most cases, the default widget is TextInput.
        # label -- A verbose name for this field, for use in displaying this
        # field in a form. By default, Django will use a "pretty"
        # version of the form field name, if the Field is part of a
        # Form.
        # initial -- A value to use in this Field's initial display. This value
        # is *not* used as a fallback if data isn't given.
        # help_text -- An optional string to use as "help text" for this Field.
        # error_messages -- An optional dictionary to override the default
        # messages that the field will raise.
        # show_hidden_initial -- Boolean that specifies if it is needed to render a
        # hidden widget with initial value after widget.
        # validators -- List of addtional validators to use
        # localize -- Boolean that specifies if the field should be localized.
        self.required, self.label, self.initial = required, label, initial
        self.show_hidden_initial = show_hidden_initial
        self.help_text = help_text
        widget = widget or self.widget
        if isinstance(widget, type):
            widget = widget()

        # Trigger the localization machinery if needed.
        self.localize = localize
        if self.localize:
            widget.is_localized = True

        # Let the widget know whether it should display as required.
        widget.is_required = self.required

        # Hook into self.widget_attrs() for any Field-specific HTML attributes.
        extra_attrs = self.widget_attrs(widget)
        if extra_attrs:
            widget.attrs.update(extra_attrs)

        self.widget = widget

        # Increase the creation counter, and save our local copy.
        self.creation_counter = Field.creation_counter
        Field.creation_counter += 1

        messages = {}
        for c in reversed(self.__class__.__mro__):
            messages.update(getattr(c, 'default_error_messages', {}))
        messages.update(error_messages or {})
        self.error_messages = messages

        self.validators = self.default_validators + validators
        super(Field, self).__init__()

    def prepare_value(self, value):
        return value

    def to_python(self, value):
        return value

    def validate(self, value):
        if value in self.empty_values and self.required:
            raise ValidationError(self.error_messages['required'], code='required')

    def run_validators(self, value):
        if value in self.empty_values:
            return
        errors = []
        for v in self.validators:
            try:
                v(value)
            except ValidationError as e:
                if hasattr(e, 'code') and e.code in self.error_messages:
                    e.message = self.error_messages[e.code]
                errors.extend(e.error_list)
        if errors:
            raise ValidationError(errors)

    def clean(self, value):
        """
Validates the given value and returns its "cleaned" value as an
appropriate Python object.

Raises ValidationError for any errors.
"""
        value = self.to_python(value)
        self.validate(value)
        self.run_validators(value)
        return value

    def bound_data(self, data, initial):
        """
Return the value that should be shown for this field on render of a
bound form, given the submitted POST data for the field and the initial
data, if any.

For most fields, this will simply be data; FileFields need to handle it
a bit differently.
"""
        return data

    def widget_attrs(self, widget):
        """
Given a Widget instance (*not* a Widget class), returns a dictionary of
any HTML attributes that should be added to the Widget, based on this
Field.
"""
        return {}

    def get_limit_choices_to(self):
        """
Returns ``limit_choices_to`` for this form field.

If it is a callable, it will be invoked and the result will be
returned.
"""
        if callable(self.limit_choices_to):
            return self.limit_choices_to()
        return self.limit_choices_to

    def _has_changed(self, initial, data):
        """
Return True if data differs from initial.
"""
        # For purposes of seeing whether something has changed, None is
        # the same as an empty string, if the data or inital value we get
        # is None, replace it w/ ''.
        initial_value = initial if initial is not None else ''
        try:
            data = self.to_python(data)
            if hasattr(self, '_coerce'):
                data = self._coerce(data)
        except ValidationError:
            return True
        data_value = data if data is not None else ''
        return initial_value != data_value

    def __deepcopy__(self, memo):
        result = copy.copy(self)
        memo[id(self)] = result
        result.widget = copy.deepcopy(self.widget, memo)
        result.validators = self.validators[:]
        return result


class CharField(Field):
    def __init__(self, max_length=None, min_length=None, *args, **kwargs):
        self.max_length, self.min_length = max_length, min_length
        super(CharField, self).__init__(*args, **kwargs)
        if min_length is not None:
            self.validators.append(validators.MinLengthValidator(int(min_length)))
        if max_length is not None:
            self.validators.append(validators.MaxLengthValidator(int(max_length)))

    def to_python(self, value):
        "Returns a Unicode object."
        if value in self.empty_values:
            return ''
        return smart_text(value)

    def widget_attrs(self, widget):
        attrs = super(CharField, self).widget_attrs(widget)
        if self.max_length is not None:
            # The HTML attribute is maxlength, not max_length.
            attrs.update({'maxlength': str(self.max_length)})
        return attrs


class IntegerField(Field):
    widget = NumberInput
    default_error_messages = {
        'invalid': _('Enter a whole number.'),
    }

    def __init__(self, max_value=None, min_value=None, *args, **kwargs):
        self.max_value, self.min_value = max_value, min_value
        if kwargs.get('localize') and self.widget == NumberInput:
            # Localized number input is not well supported on most browsers
            kwargs.setdefault('widget', super(IntegerField, self).widget)
        super(IntegerField, self).__init__(*args, **kwargs)

        if max_value is not None:
            self.validators.append(validators.MaxValueValidator(max_value))
        if min_value is not None:
            self.validators.append(validators.MinValueValidator(min_value))

    def to_python(self, value):
        """
Validates that int() can be called on the input. Returns the result
of int(). Returns None for empty values.
"""
        value = super(IntegerField, self).to_python(value)
        if value in self.empty_values:
            return None
        if self.localize:
            value = formats.sanitize_separators(value)
        try:
            value = int(str(value))
        except (ValueError, TypeError):
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        return value

    def widget_attrs(self, widget):
        attrs = super(IntegerField, self).widget_attrs(widget)
        if isinstance(widget, NumberInput):
            if self.min_value is not None:
                attrs['min'] = self.min_value
            if self.max_value is not None:
                attrs['max'] = self.max_value
        return attrs


class FloatField(IntegerField):
    default_error_messages = {
        'invalid': _('Enter a number.'),
    }

    def to_python(self, value):
        """
Validates that float() can be called on the input. Returns the result
of float(). Returns None for empty values.
"""
        value = super(IntegerField, self).to_python(value)
        if value in self.empty_values:
            return None
        if self.localize:
            value = formats.sanitize_separators(value)
        try:
            value = float(value)
        except (ValueError, TypeError):
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        return value

    def validate(self, value):
        super(FloatField, self).validate(value)

        # Check for NaN (which is the only thing not equal to itself) and +/- infinity
        if value != value or value in (Decimal('Inf'), Decimal('-Inf')):
            raise ValidationError(self.error_messages['invalid'], code='invalid')

        return value

    def widget_attrs(self, widget):
        attrs = super(FloatField, self).widget_attrs(widget)
        if isinstance(widget, NumberInput) and 'step' not in widget.attrs:
            attrs.setdefault('step', 'any')
        return attrs


class DecimalField(IntegerField):
    default_error_messages = {
        'invalid': _('Enter a number.'),
        'max_digits': ungettext_lazy(
            'Ensure that there are no more than %(max)s digit in total.',
            'Ensure that there are no more than %(max)s digits in total.',
            'max'),
        'max_decimal_places': ungettext_lazy(
            'Ensure that there are no more than %(max)s decimal place.',
            'Ensure that there are no more than %(max)s decimal places.',
            'max'),
        'max_whole_digits': ungettext_lazy(
            'Ensure that there are no more than %(max)s digit before the decimal point.',
            'Ensure that there are no more than %(max)s digits before the decimal point.',
            'max'),
    }

    def __init__(self, max_value=None, min_value=None, max_digits=None, decimal_places=None, *args, **kwargs):
        self.max_digits, self.decimal_places = max_digits, decimal_places
        super(DecimalField, self).__init__(max_value, min_value, *args, **kwargs)

    def to_python(self, value):
        """
Validates that the input is a decimal number. Returns a Decimal
instance. Returns None for empty values. Ensures that there are no more
than max_digits in the number, and no more than decimal_places digits
after the decimal point.
"""
        if value in self.empty_values:
            return None
        if self.localize:
            value = formats.sanitize_separators(value)
        value = smart_text(value).strip()
        try:
            value = Decimal(value)
        except DecimalException:
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        return value

    def validate(self, value):
        super(DecimalField, self).validate(value)
        if value in self.empty_values:
            return
        # Check for NaN, Inf and -Inf values. We can't compare directly for NaN,
        # since it is never equal to itself. However, NaN is the only value that
        # isn't equal to itself, so we can use this to identify NaN
        if value != value or value == Decimal("Inf") or value == Decimal("-Inf"):
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        sign, digittuple, exponent = value.as_tuple()
        decimals = abs(exponent)
        # digittuple doesn't include any leading zeros.
        digits = len(digittuple)
        if decimals > digits:
            # We have leading zeros up to or past the decimal point. Count
            # everything past the decimal point as a digit. We do not count
            # 0 before the decimal point as a digit since that would mean
            # we would not allow max_digits = decimal_places.
            digits = decimals
        whole_digits = digits - decimals

        if self.max_digits is not None and digits > self.max_digits:
            raise ValidationError(
                self.error_messages['max_digits'],
                code='max_digits',
                params={'max': self.max_digits},
            )
        if self.decimal_places is not None and decimals > self.decimal_places:
            raise ValidationError(
                self.error_messages['max_decimal_places'],
                code='max_decimal_places',
                params={'max': self.decimal_places},
            )
        if (self.max_digits is not None and self.decimal_places is not None
                and whole_digits > (self.max_digits - self.decimal_places)):
            raise ValidationError(
                self.error_messages['max_whole_digits'],
                code='max_whole_digits',
                params={'max': (self.max_digits - self.decimal_places)},
            )
        return value

    def widget_attrs(self, widget):
        attrs = super(DecimalField, self).widget_attrs(widget)
        if isinstance(widget, NumberInput) and 'step' not in widget.attrs:
            if self.decimal_places is not None:
                # Use exponential notation for small values since they might
                # be parsed as 0 otherwise. ref #20765
                step = str(Decimal('1') / 10 ** self.decimal_places).lower()
            else:
                step = 'any'
            attrs.setdefault('step', step)
        return attrs


class BaseTemporalField(Field):

    def __init__(self, input_formats=None, *args, **kwargs):
        super(BaseTemporalField, self).__init__(*args, **kwargs)
        if input_formats is not None:
            self.input_formats = input_formats

    def to_python(self, value):
        # Try to coerce the value to unicode.
        unicode_value = force_text(value, strings_only=True)
        if isinstance(unicode_value, six.text_type):
            value = unicode_value.strip()
        # If unicode, try to strptime against each input format.
        if isinstance(value, six.text_type):
            for format in self.input_formats:
                try:
                    return self.strptime(value, format)
                except (ValueError, TypeError):
                    continue
        raise ValidationError(self.error_messages['invalid'], code='invalid')

    def strptime(self, value, format):
        raise NotImplementedError('Subclasses must define this method.')


class DateField(BaseTemporalField):
    widget = DateInput
    input_formats = formats.get_format_lazy('DATE_INPUT_FORMATS')
    default_error_messages = {
        'invalid': _('Enter a valid date.'),
    }

    def to_python(self, value):
        """
Validates that the input can be converted to a date. Returns a Python
datetime.date object.
"""
        if value in self.empty_values:
            return None
        if isinstance(value, datetime.datetime):
            return value.date()
        if isinstance(value, datetime.date):
            return value
        return super(DateField, self).to_python(value)

    def strptime(self, value, format):
        return datetime.datetime.strptime(force_str(value), format).date()


class TimeField(BaseTemporalField):
    widget = TimeInput
    input_formats = formats.get_format_lazy('TIME_INPUT_FORMATS')
    default_error_messages = {
        'invalid': _('Enter a valid time.')
    }

    def to_python(self, value):
        """
Validates that the input can be converted to a time. Returns a Python
datetime.time object.
"""
        if value in self.empty_values:
            return None
        if isinstance(value, datetime.time):
            return value
        return super(TimeField, self).to_python(value)

    def strptime(self, value, format):
        return datetime.datetime.strptime(force_str(value), format).time()


class DateTimeField(BaseTemporalField):
    widget = DateTimeInput
    input_formats = formats.get_format_lazy('DATETIME_INPUT_FORMATS')
    default_error_messages = {
        'invalid': _('Enter a valid date/time.'),
    }

    def prepare_value(self, value):
        if isinstance(value, datetime.datetime):
            value = to_current_timezone(value)
        return value

    def to_python(self, value):
        """
Validates that the input can be converted to a datetime. Returns a
Python datetime.datetime object.
"""
        if value in self.empty_values:
            return None
        if isinstance(value, datetime.datetime):
            return from_current_timezone(value)
        if isinstance(value, datetime.date):
            result = datetime.datetime(value.year, value.month, value.day)
            return from_current_timezone(result)
        if isinstance(value, list):
            # Input comes from a SplitDateTimeWidget, for example. So, it's two
            # components: date and time.
            warnings.warn(
                'Using SplitDateTimeWidget with DateTimeField is deprecated. '
                'Use SplitDateTimeField instead.',
                RemovedInDjango19Warning, stacklevel=2)
            if len(value) != 2:
                raise ValidationError(self.error_messages['invalid'], code='invalid')
            if value[0] in self.empty_values and value[1] in self.empty_values:
                return None
            value = '%s %s' % tuple(value)
        result = super(DateTimeField, self).to_python(value)
        return from_current_timezone(result)

    def strptime(self, value, format):
        return datetime.datetime.strptime(force_str(value), format)


class RegexField(CharField):
    def __init__(self, regex, max_length=None, min_length=None, error_message=None, *args, **kwargs):
        """
regex can be either a string or a compiled regular expression object.
error_message is an optional error message to use, if
'Enter a valid value' is too generic for you.
"""
        # error_message is just kept for backwards compatibility:
        if error_message:
            error_messages = kwargs.get('error_messages') or {}
            error_messages['invalid'] = error_message
            kwargs['error_messages'] = error_messages
        super(RegexField, self).__init__(max_length, min_length, *args, **kwargs)
        self._set_regex(regex)

    def _get_regex(self):
        return self._regex

    def _set_regex(self, regex):
        if isinstance(regex, six.string_types):
            regex = re.compile(regex, re.UNICODE)
        self._regex = regex
        if hasattr(self, '_regex_validator') and self._regex_validator in self.validators:
            self.validators.remove(self._regex_validator)
        self._regex_validator = validators.RegexValidator(regex=regex)
        self.validators.append(self._regex_validator)

    regex = property(_get_regex, _set_regex)


class EmailField(CharField):
    widget = EmailInput
    default_validators = [validators.validate_email]

    def clean(self, value):
        value = self.to_python(value).strip()
        return super(EmailField, self).clean(value)


class FileField(Field):
    widget = ClearableFileInput
    default_error_messages = {
        'invalid': _("No file was submitted. Check the encoding type on the form."),
        'missing': _("No file was submitted."),
        'empty': _("The submitted file is empty."),
        'max_length': ungettext_lazy(
            'Ensure this filename has at most %(max)d character (it has %(length)d).',
            'Ensure this filename has at most %(max)d characters (it has %(length)d).',
            'max'),
        'contradiction': _('Please either submit a file or check the clear checkbox, not both.')
    }

    def __init__(self, *args, **kwargs):
        self.max_length = kwargs.pop('max_length', None)
        self.allow_empty_file = kwargs.pop('allow_empty_file', False)
        super(FileField, self).__init__(*args, **kwargs)

    def to_python(self, data):
        if data in self.empty_values:
            return None

        # UploadedFile objects should have name and size attributes.
        try:
            file_name = data.name
            file_size = data.size
        except AttributeError:
            raise ValidationError(self.error_messages['invalid'], code='invalid')

        if self.max_length is not None and len(file_name) > self.max_length:
            params = {'max': self.max_length, 'length': len(file_name)}
            raise ValidationError(self.error_messages['max_length'], code='max_length', params=params)
        if not file_name:
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        if not self.allow_empty_file and not file_size:
            raise ValidationError(self.error_messages['empty'], code='empty')

        return data

    def clean(self, data, initial=None):
        # If the widget got contradictory inputs, we raise a validation error
        if data is FILE_INPUT_CONTRADICTION:
            raise ValidationError(self.error_messages['contradiction'], code='contradiction')
        # False means the field value should be cleared; further validation is
        # not needed.
        if data is False:
            if not self.required:
                return False
            # If the field is required, clearing is not possible (the widget
            # shouldn't return False data in that case anyway). False is not
            # in self.empty_value; if a False value makes it this far
            # it should be validated from here on out as None (so it will be
            # caught by the required check).
            data = None
        if not data and initial:
            return initial
        return super(FileField, self).clean(data)

    def bound_data(self, data, initial):
        if data in (None, FILE_INPUT_CONTRADICTION):
            return initial
        return data

    def _has_changed(self, initial, data):
        if data is None:
            return False
        return True


class ImageField(FileField):
    default_error_messages = {
        'invalid_image': _("Upload a valid image. The file you uploaded was either not an image or a corrupted image."),
    }

    def to_python(self, data):
        """
Checks that the file-upload field data contains a valid image (GIF, JPG,
PNG, possibly others -- whatever the Python Imaging Library supports).
"""
        f = super(ImageField, self).to_python(data)
        if f is None:
            return None

        from PIL import Image

        # We need to get a file object for Pillow. We might have a path or we might
        # have to read the data into memory.
        if hasattr(data, 'temporary_file_path'):
            file = data.temporary_file_path()
        else:
            if hasattr(data, 'read'):
                file = BytesIO(data.read())
            else:
                file = BytesIO(data['content'])

        try:
            # load() could spot a truncated JPEG, but it loads the entire
            # image in memory, which is a DoS vector. See #3848 and #18520.
            # verify() must be called immediately after the constructor.
            Image.open(file).verify()
        except Exception:
            # Pillow doesn't recognize it as an image.
            six.reraise(ValidationError, ValidationError(
                self.error_messages['invalid_image'],
                code='invalid_image',
            ), sys.exc_info()[2])
        if hasattr(f, 'seek') and callable(f.seek):
            f.seek(0)
        return f


class URLField(CharField):
    widget = URLInput
    default_error_messages = {
        'invalid': _('Enter a valid URL.'),
    }
    default_validators = [validators.URLValidator()]

    def to_python(self, value):

        def split_url(url):
            """
Returns a list of url parts via ``urlparse.urlsplit`` (or raises a
``ValidationError`` exception for certain).
"""
            try:
                return list(urlsplit(url))
            except ValueError:
                # urlparse.urlsplit can raise a ValueError with some
                # misformatted URLs.
                raise ValidationError(self.error_messages['invalid'], code='invalid')

        value = super(URLField, self).to_python(value)
        if value:
            url_fields = split_url(value)
            if not url_fields[0]:
                # If no URL scheme given, assume http://
                url_fields[0] = 'http'
            if not url_fields[1]:
                # Assume that if no domain is provided, that the path segment
                # contains the domain.
                url_fields[1] = url_fields[2]
                url_fields[2] = ''
                # Rebuild the url_fields list, since the domain segment may now
                # contain the path too.
                url_fields = split_url(urlunsplit(url_fields))
            value = urlunsplit(url_fields)
        return value

    def clean(self, value):
        value = self.to_python(value).strip()
        return super(URLField, self).clean(value)


class BooleanField(Field):
    widget = CheckboxInput

    def to_python(self, value):
        """Returns a Python boolean object."""
        # Explicitly check for the string 'False', which is what a hidden field
        # will submit for False. Also check for '0', since this is what
        # RadioSelect will provide. Because bool("True") == bool('1') == True,
        # we don't need to handle that explicitly.
        if isinstance(value, six.string_types) and value.lower() in ('false', '0'):
            value = False
        else:
            value = bool(value)
        return super(BooleanField, self).to_python(value)

    def validate(self, value):
        if not value and self.required:
            raise ValidationError(self.error_messages['required'], code='required')

    def _has_changed(self, initial, data):
        # Sometimes data or initial could be None or '' which should be the
        # same thing as False.
        if initial == 'False':
            # show_hidden_initial may have transformed False to 'False'
            initial = False
        return bool(initial) != bool(data)


class NullBooleanField(BooleanField):
    """
A field whose valid values are None, True and False. Invalid values are
cleaned to None.
"""
    widget = NullBooleanSelect

    def to_python(self, value):
        """
Explicitly checks for the string 'True' and 'False', which is what a
hidden field will submit for True and False, and for '1' and '0', which
is what a RadioField will submit. Unlike the Booleanfield we need to
explicitly check for True, because we are not using the bool() function
"""
        if value in (True, 'True', '1'):
            return True
        elif value in (False, 'False', '0'):
            return False
        else:
            return None

    def validate(self, value):
        pass

    def _has_changed(self, initial, data):
        # None (unknown) and False (No) are not the same
        if initial is not None:
            initial = bool(initial)
        if data is not None:
            data = bool(data)
        return initial != data


class ChoiceField(Field):
    widget = Select
    default_error_messages = {
        'invalid_choice': _('Select a valid choice. %(value)s is not one of the available choices.'),
    }

    def __init__(self, choices=(), required=True, widget=None, label=None,
                 initial=None, help_text='', *args, **kwargs):
        super(ChoiceField, self).__init__(required=required, widget=widget, label=label,
                                        initial=initial, help_text=help_text, *args, **kwargs)
        self.choices = choices

    def __deepcopy__(self, memo):
        result = super(ChoiceField, self).__deepcopy__(memo)
        result._choices = copy.deepcopy(self._choices, memo)
        return result

    def _get_choices(self):
        return self._choices

    def _set_choices(self, value):
        # Setting choices also sets the choices on the widget.
        # choices can be any iterable, but we call list() on it because
        # it will be consumed more than once.
        self._choices = self.widget.choices = list(value)

    choices = property(_get_choices, _set_choices)

    def to_python(self, value):
        "Returns a Unicode object."
        if value in self.empty_values:
            return ''
        return smart_text(value)

    def validate(self, value):
        """
Validates that the input is in self.choices.
"""
        super(ChoiceField, self).validate(value)
        if value and not self.valid_value(value):
            raise ValidationError(
                self.error_messages['invalid_choice'],
                code='invalid_choice',
                params={'value': value},
            )

    def valid_value(self, value):
        "Check to see if the provided value is a valid choice"
        text_value = force_text(value)
        for k, v in self.choices:
            if isinstance(v, (list, tuple)):
                # This is an optgroup, so look inside the group for options
                for k2, v2 in v:
                    if value == k2 or text_value == force_text(k2):
                        return True
            else:
                if value == k or text_value == force_text(k):
                    return True
        return False


class TypedChoiceField(ChoiceField):
    def __init__(self, *args, **kwargs):
        self.coerce = kwargs.pop('coerce', lambda val: val)
        self.empty_value = kwargs.pop('empty_value', '')
        super(TypedChoiceField, self).__init__(*args, **kwargs)

    def _coerce(self, value):
        """
Validate that the value can be coerced to the right type (if not empty).
"""
        if value == self.empty_value or value in self.empty_values:
            return self.empty_value
        try:
            value = self.coerce(value)
        except (ValueError, TypeError, ValidationError):
            raise ValidationError(
                self.error_messages['invalid_choice'],
                code='invalid_choice',
                params={'value': value},
            )
        return value

    def clean(self, value):
        value = super(TypedChoiceField, self).clean(value)
        return self._coerce(value)


class MultipleChoiceField(ChoiceField):
    hidden_widget = MultipleHiddenInput
    widget = SelectMultiple
    default_error_messages = {
        'invalid_choice': _('Select a valid choice. %(value)s is not one of the available choices.'),
        'invalid_list': _('Enter a list of values.'),
    }

    def to_python(self, value):
        if not value:
            return []
        elif not isinstance(value, (list, tuple)):
            raise ValidationError(self.error_messages['invalid_list'], code='invalid_list')
        return [smart_text(val) for val in value]

    def validate(self, value):
        """
Validates that the input is a list or tuple.
"""
        if self.required and not value:
            raise ValidationError(self.error_messages['required'], code='required')
        # Validate that each value in the value list is in self.choices.
        for val in value:
            if not self.valid_value(val):
                raise ValidationError(
                    self.error_messages['invalid_choice'],
                    code='invalid_choice',
                    params={'value': val},
                )

    def _has_changed(self, initial, data):
        if initial is None:
            initial = []
        if data is None:
            data = []
        if len(initial) != len(data):
            return True
        initial_set = set(force_text(value) for value in initial)
        data_set = set(force_text(value) for value in data)
        return data_set != initial_set


class TypedMultipleChoiceField(MultipleChoiceField):
    def __init__(self, *args, **kwargs):
        self.coerce = kwargs.pop('coerce', lambda val: val)
        self.empty_value = kwargs.pop('empty_value', [])
        super(TypedMultipleChoiceField, self).__init__(*args, **kwargs)

    def _coerce(self, value):
        """
Validates that the values are in self.choices and can be coerced to the
right type.
"""
        if value == self.empty_value or value in self.empty_values:
            return self.empty_value
        new_value = []
        for choice in value:
            try:
                new_value.append(self.coerce(choice))
            except (ValueError, TypeError, ValidationError):
                raise ValidationError(
                    self.error_messages['invalid_choice'],
                    code='invalid_choice',
                    params={'value': choice},
                )
        return new_value

    def clean(self, value):
        value = super(TypedMultipleChoiceField, self).clean(value)
        return self._coerce(value)

    def validate(self, value):
        if value != self.empty_value:
            super(TypedMultipleChoiceField, self).validate(value)
        elif self.required:
            raise ValidationError(self.error_messages['required'], code='required')


class ComboField(Field):
    """
A Field whose clean() method calls multiple Field clean() methods.
"""
    def __init__(self, fields=(), *args, **kwargs):
        super(ComboField, self).__init__(*args, **kwargs)
        # Set 'required' to False on the individual fields, because the
        # required validation will be handled by ComboField, not by those
        # individual fields.
        for f in fields:
            f.required = False
        self.fields = fields

    def clean(self, value):
        """
Validates the given value against all of self.fields, which is a
list of Field instances.
"""
        super(ComboField, self).clean(value)
        for field in self.fields:
            value = field.clean(value)
        return value


class MultiValueField(Field):
    """
A Field that aggregates the logic of multiple Fields.

Its clean() method takes a "decompressed" list of values, which are then
cleaned into a single value according to self.fields. Each value in
this list is cleaned by the corresponding field -- the first value is
cleaned by the first field, the second value is cleaned by the second
field, etc. Once all fields are cleaned, the list of clean values is
"compressed" into a single value.

Subclasses should not have to implement clean(). Instead, they must
implement compress(), which takes a list of valid values and returns a
"compressed" version of those values -- a single value.

You'll probably want to use this with MultiWidget.
"""
    default_error_messages = {
        'invalid': _('Enter a list of values.'),
        'incomplete': _('Enter a complete value.'),
    }

    def __init__(self, fields=(), *args, **kwargs):
        self.require_all_fields = kwargs.pop('require_all_fields', True)
        super(MultiValueField, self).__init__(*args, **kwargs)
        for f in fields:
            f.error_messages.setdefault('incomplete',
                                        self.error_messages['incomplete'])
            if self.require_all_fields:
                # Set 'required' to False on the individual fields, because the
                # required validation will be handled by MultiValueField, not
                # by those individual fields.
                f.required = False
        self.fields = fields

    def __deepcopy__(self, memo):
        result = super(MultiValueField, self).__deepcopy__(memo)
        result.fields = tuple([x.__deepcopy__(memo) for x in self.fields])
        return result

    def validate(self, value):
        pass

    def clean(self, value):
        """
Validates every value in the given list. A value is validated against
the corresponding Field in self.fields.

For example, if this MultiValueField was instantiated with
fields=(DateField(), TimeField()), clean() would call
DateField.clean(value[0]) and TimeField.clean(value[1]).
"""
        clean_data = []
        errors = []
        if not value or isinstance(value, (list, tuple)):
            if not value or not [v for v in value if v not in self.empty_values]:
                if self.required:
                    raise ValidationError(self.error_messages['required'], code='required')
                else:
                    return self.compress([])
        else:
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        for i, field in enumerate(self.fields):
            try:
                field_value = value[i]
            except IndexError:
                field_value = None
            if field_value in self.empty_values:
                if self.require_all_fields:
                    # Raise a 'required' error if the MultiValueField is
                    # required and any field is empty.
                    if self.required:
                        raise ValidationError(self.error_messages['required'], code='required')
                elif field.required:
                    # Otherwise, add an 'incomplete' error to the list of
                    # collected errors and skip field cleaning, if a required
                    # field is empty.
                    if field.error_messages['incomplete'] not in errors:
                        errors.append(field.error_messages['incomplete'])
                    continue
            try:
                clean_data.append(field.clean(field_value))
            except ValidationError as e:
                # Collect all validation errors in a single list, which we'll
                # raise at the end of clean(), rather than raising a single
                # exception for the first error we encounter. Skip duplicates.
                errors.extend(m for m in e.error_list if m not in errors)
        if errors:
            raise ValidationError(errors)

        out = self.compress(clean_data)
        self.validate(out)
        self.run_validators(out)
        return out

    def compress(self, data_list):
        """
Returns a single value for the given list of values. The values can be
assumed to be valid.

For example, if this MultiValueField was instantiated with
fields=(DateField(), TimeField()), this might return a datetime
object created by combining the date and time in data_list.
"""
        raise NotImplementedError('Subclasses must implement this method.')

    def _has_changed(self, initial, data):
        if initial is None:
            initial = ['' for x in range(0, len(data))]
        else:
            if not isinstance(initial, list):
                initial = self.widget.decompress(initial)
        for field, initial, data in zip(self.fields, initial, data):
            if field._has_changed(field.to_python(initial), data):
                return True
        return False


class FilePathField(ChoiceField):
    def __init__(self, path, match=None, recursive=False, allow_files=True,
                 allow_folders=False, required=True, widget=None, label=None,
                 initial=None, help_text='', *args, **kwargs):
        self.path, self.match, self.recursive = path, match, recursive
        self.allow_files, self.allow_folders = allow_files, allow_folders
        super(FilePathField, self).__init__(choices=(), required=required,
            widget=widget, label=label, initial=initial, help_text=help_text,
            *args, **kwargs)

        if self.required:
            self.choices = []
        else:
            self.choices = [("", "---------")]

        if self.match is not None:
            self.match_re = re.compile(self.match)

        if recursive:
            for root, dirs, files in sorted(os.walk(self.path)):
                if self.allow_files:
                    for f in files:
                        if self.match is None or self.match_re.search(f):
                            f = os.path.join(root, f)
                            self.choices.append((f, f.replace(path, "", 1)))
                if self.allow_folders:
                    for f in dirs:
                        if f == '__pycache__':
                            continue
                        if self.match is None or self.match_re.search(f):
                            f = os.path.join(root, f)
                            self.choices.append((f, f.replace(path, "", 1)))
        else:
            try:
                for f in sorted(os.listdir(self.path)):
                    if f == '__pycache__':
                        continue
                    full_file = os.path.join(self.path, f)
                    if (((self.allow_files and os.path.isfile(full_file)) or
                            (self.allow_folders and os.path.isdir(full_file))) and
                            (self.match is None or self.match_re.search(f))):
                        self.choices.append((full_file, f))
            except OSError:
                pass

        self.widget.choices = self.choices


class SplitDateTimeField(MultiValueField):
    widget = SplitDateTimeWidget
    hidden_widget = SplitHiddenDateTimeWidget
    default_error_messages = {
        'invalid_date': _('Enter a valid date.'),
        'invalid_time': _('Enter a valid time.'),
    }

    def __init__(self, input_date_formats=None, input_time_formats=None, *args, **kwargs):
        errors = self.default_error_messages.copy()
        if 'error_messages' in kwargs:
            errors.update(kwargs['error_messages'])
        localize = kwargs.get('localize', False)
        fields = (
            DateField(input_formats=input_date_formats,
                      error_messages={'invalid': errors['invalid_date']},
                      localize=localize),
            TimeField(input_formats=input_time_formats,
                      error_messages={'invalid': errors['invalid_time']},
                      localize=localize),
        )
        super(SplitDateTimeField, self).__init__(fields, *args, **kwargs)

    def compress(self, data_list):
        if data_list:
            # Raise a validation error if time or date is empty
            # (possible if SplitDateTimeField has required=False).
            if data_list[0] in self.empty_values:
                raise ValidationError(self.error_messages['invalid_date'], code='invalid_date')
            if data_list[1] in self.empty_values:
                raise ValidationError(self.error_messages['invalid_time'], code='invalid_time')
            result = datetime.datetime.combine(*data_list)
            return from_current_timezone(result)
        return None


class IPAddressField(CharField):
    default_validators = [validators.validate_ipv4_address]

    def __init__(self, *args, **kwargs):
        warnings.warn("IPAddressField has been deprecated. Use GenericIPAddressField instead.",
                      RemovedInDjango19Warning)
        super(IPAddressField, self).__init__(*args, **kwargs)

    def to_python(self, value):
        if value in self.empty_values:
            return ''
        return value.strip()


class GenericIPAddressField(CharField):
    def __init__(self, protocol='both', unpack_ipv4=False, *args, **kwargs):
        self.unpack_ipv4 = unpack_ipv4
        self.default_validators = validators.ip_address_validators(protocol, unpack_ipv4)[0]
        super(GenericIPAddressField, self).__init__(*args, **kwargs)

    def to_python(self, value):
        if value in self.empty_values:
            return ''
        value = value.strip()
        if value and ':' in value:
            return clean_ipv6_address(value, self.unpack_ipv4)
        return value


class SlugField(CharField):
    default_validators = [validators.validate_slug]

    def clean(self, value):
        value = self.to_python(value).strip()
        return super(SlugField, self).clean(value)
Something went wrong with that request. Please try again.