app/django/forms/fields.py
changeset 323 ff1a9aa48cfd
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/forms/fields.py	Tue Oct 14 16:00:59 2008 +0000
@@ -0,0 +1,892 @@
+"""
+Field classes.
+"""
+
+import copy
+import datetime
+import os
+import re
+import time
+import urlparse
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from StringIO import StringIO
+
+# Python 2.3 fallbacks
+try:
+    from decimal import Decimal, DecimalException
+except ImportError:
+    from django.utils._decimal import Decimal, DecimalException
+try:
+    set
+except NameError:
+    from sets import Set as set
+
+import django.core.exceptions
+from django.utils.translation import ugettext_lazy as _
+from django.utils.encoding import smart_unicode, smart_str
+
+from util import ErrorList, ValidationError
+from widgets import TextInput, PasswordInput, HiddenInput, MultipleHiddenInput, FileInput, CheckboxInput, Select, NullBooleanSelect, SelectMultiple, DateTimeInput, TimeInput, SplitHiddenDateTimeWidget
+from django.core.files.uploadedfile import SimpleUploadedFile as UploadedFile
+
+__all__ = (
+    'Field', 'CharField', 'IntegerField',
+    'DEFAULT_DATE_INPUT_FORMATS', 'DateField',
+    'DEFAULT_TIME_INPUT_FORMATS', 'TimeField',
+    'DEFAULT_DATETIME_INPUT_FORMATS', 'DateTimeField', 'TimeField',
+    'RegexField', 'EmailField', 'FileField', 'ImageField', 'URLField',
+    'BooleanField', 'NullBooleanField', 'ChoiceField', 'MultipleChoiceField',
+    'ComboField', 'MultiValueField', 'FloatField', 'DecimalField',
+    'SplitDateTimeField', 'IPAddressField', 'FilePathField', 'SlugField',
+    'TypedChoiceField'
+)
+
+# These values, if given to to_python(), will trigger the self.required check.
+EMPTY_VALUES = (None, '')
+
+
+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_error_messages = {
+        'required': _(u'This field is required.'),
+        'invalid': _(u'Enter a valid value.'),
+    }
+
+    # 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=None, error_messages=None, show_hidden_initial=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.
+        # show_hidden_initial -- Boolean that specifies if it is needed to render a
+        #                        hidden widget with initial value after widget.
+        if label is not None:
+            label = smart_unicode(label)
+        self.required, self.label, self.initial = required, label, initial
+        self.show_hidden_initial = show_hidden_initial
+        if help_text is None:
+            self.help_text = u''
+        else:
+            self.help_text = smart_unicode(help_text)
+        widget = widget or self.widget
+        if isinstance(widget, type):
+            widget = widget()
+
+        # 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
+
+        def set_class_error_messages(messages, klass):
+            for base_class in klass.__bases__:
+                set_class_error_messages(messages, base_class)
+            messages.update(getattr(klass, 'default_error_messages', {}))
+
+        messages = {}
+        set_class_error_messages(messages, self.__class__)
+        messages.update(error_messages or {})
+        self.error_messages = messages
+
+    def clean(self, value):
+        """
+        Validates the given value and returns its "cleaned" value as an
+        appropriate Python object.
+
+        Raises ValidationError for any errors.
+        """
+        if self.required and value in EMPTY_VALUES:
+            raise ValidationError(self.error_messages['required'])
+        return value
+
+    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 __deepcopy__(self, memo):
+        result = copy.copy(self)
+        memo[id(self)] = result
+        result.widget = copy.deepcopy(self.widget, memo)
+        return result
+
+class CharField(Field):
+    default_error_messages = {
+        'max_length': _(u'Ensure this value has at most %(max)d characters (it has %(length)d).'),
+        'min_length': _(u'Ensure this value has at least %(min)d characters (it has %(length)d).'),
+    }
+
+    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)
+
+    def clean(self, value):
+        "Validates max_length and min_length. Returns a Unicode object."
+        super(CharField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return u''
+        value = smart_unicode(value)
+        value_length = len(value)
+        if self.max_length is not None and value_length > self.max_length:
+            raise ValidationError(self.error_messages['max_length'] % {'max': self.max_length, 'length': value_length})
+        if self.min_length is not None and value_length < self.min_length:
+            raise ValidationError(self.error_messages['min_length'] % {'min': self.min_length, 'length': value_length})
+        return value
+
+    def widget_attrs(self, widget):
+        if self.max_length is not None and isinstance(widget, (TextInput, PasswordInput)):
+            # The HTML attribute is maxlength, not max_length.
+            return {'maxlength': str(self.max_length)}
+
+class IntegerField(Field):
+    default_error_messages = {
+        'invalid': _(u'Enter a whole number.'),
+        'max_value': _(u'Ensure this value is less than or equal to %s.'),
+        'min_value': _(u'Ensure this value is greater than or equal to %s.'),
+    }
+
+    def __init__(self, max_value=None, min_value=None, *args, **kwargs):
+        self.max_value, self.min_value = max_value, min_value
+        super(IntegerField, self).__init__(*args, **kwargs)
+
+    def clean(self, value):
+        """
+        Validates that int() can be called on the input. Returns the result
+        of int(). Returns None for empty values.
+        """
+        super(IntegerField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return None
+        try:
+            value = int(str(value))
+        except (ValueError, TypeError):
+            raise ValidationError(self.error_messages['invalid'])
+        if self.max_value is not None and value > self.max_value:
+            raise ValidationError(self.error_messages['max_value'] % self.max_value)
+        if self.min_value is not None and value < self.min_value:
+            raise ValidationError(self.error_messages['min_value'] % self.min_value)
+        return value
+
+class FloatField(Field):
+    default_error_messages = {
+        'invalid': _(u'Enter a number.'),
+        'max_value': _(u'Ensure this value is less than or equal to %s.'),
+        'min_value': _(u'Ensure this value is greater than or equal to %s.'),
+    }
+
+    def __init__(self, max_value=None, min_value=None, *args, **kwargs):
+        self.max_value, self.min_value = max_value, min_value
+        Field.__init__(self, *args, **kwargs)
+
+    def clean(self, value):
+        """
+        Validates that float() can be called on the input. Returns a float.
+        Returns None for empty values.
+        """
+        super(FloatField, self).clean(value)
+        if not self.required and value in EMPTY_VALUES:
+            return None
+        try:
+            value = float(value)
+        except (ValueError, TypeError):
+            raise ValidationError(self.error_messages['invalid'])
+        if self.max_value is not None and value > self.max_value:
+            raise ValidationError(self.error_messages['max_value'] % self.max_value)
+        if self.min_value is not None and value < self.min_value:
+            raise ValidationError(self.error_messages['min_value'] % self.min_value)
+        return value
+
+class DecimalField(Field):
+    default_error_messages = {
+        'invalid': _(u'Enter a number.'),
+        'max_value': _(u'Ensure this value is less than or equal to %s.'),
+        'min_value': _(u'Ensure this value is greater than or equal to %s.'),
+        'max_digits': _('Ensure that there are no more than %s digits in total.'),
+        'max_decimal_places': _('Ensure that there are no more than %s decimal places.'),
+        'max_whole_digits': _('Ensure that there are no more than %s digits before the decimal point.')
+    }
+
+    def __init__(self, max_value=None, min_value=None, max_digits=None, decimal_places=None, *args, **kwargs):
+        self.max_value, self.min_value = max_value, min_value
+        self.max_digits, self.decimal_places = max_digits, decimal_places
+        Field.__init__(self, *args, **kwargs)
+
+    def clean(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.
+        """
+        super(DecimalField, self).clean(value)
+        if not self.required and value in EMPTY_VALUES:
+            return None
+        value = smart_str(value).strip()
+        try:
+            value = Decimal(value)
+        except DecimalException:
+            raise ValidationError(self.error_messages['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 also add one
+            # for leading zeros before the decimal point (any number of leading
+            # whole zeros collapse to one digit).
+            digits = decimals + 1
+        whole_digits = digits - decimals
+
+        if self.max_value is not None and value > self.max_value:
+            raise ValidationError(self.error_messages['max_value'] % self.max_value)
+        if self.min_value is not None and value < self.min_value:
+            raise ValidationError(self.error_messages['min_value'] % self.min_value)
+        if self.max_digits is not None and digits > self.max_digits:
+            raise ValidationError(self.error_messages['max_digits'] % self.max_digits)
+        if self.decimal_places is not None and decimals > self.decimal_places:
+            raise ValidationError(self.error_messages['max_decimal_places'] % 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'] % (self.max_digits - self.decimal_places))
+        return value
+
+DEFAULT_DATE_INPUT_FORMATS = (
+    '%Y-%m-%d', '%m/%d/%Y', '%m/%d/%y', # '2006-10-25', '10/25/2006', '10/25/06'
+    '%b %d %Y', '%b %d, %Y',            # 'Oct 25 2006', 'Oct 25, 2006'
+    '%d %b %Y', '%d %b, %Y',            # '25 Oct 2006', '25 Oct, 2006'
+    '%B %d %Y', '%B %d, %Y',            # 'October 25 2006', 'October 25, 2006'
+    '%d %B %Y', '%d %B, %Y',            # '25 October 2006', '25 October, 2006'
+)
+
+class DateField(Field):
+    default_error_messages = {
+        'invalid': _(u'Enter a valid date.'),
+    }
+
+    def __init__(self, input_formats=None, *args, **kwargs):
+        super(DateField, self).__init__(*args, **kwargs)
+        self.input_formats = input_formats or DEFAULT_DATE_INPUT_FORMATS
+
+    def clean(self, value):
+        """
+        Validates that the input can be converted to a date. Returns a Python
+        datetime.date object.
+        """
+        super(DateField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return None
+        if isinstance(value, datetime.datetime):
+            return value.date()
+        if isinstance(value, datetime.date):
+            return value
+        for format in self.input_formats:
+            try:
+                return datetime.date(*time.strptime(value, format)[:3])
+            except ValueError:
+                continue
+        raise ValidationError(self.error_messages['invalid'])
+
+DEFAULT_TIME_INPUT_FORMATS = (
+    '%H:%M:%S',     # '14:30:59'
+    '%H:%M',        # '14:30'
+)
+
+class TimeField(Field):
+    widget = TimeInput
+    default_error_messages = {
+        'invalid': _(u'Enter a valid time.')
+    }
+
+    def __init__(self, input_formats=None, *args, **kwargs):
+        super(TimeField, self).__init__(*args, **kwargs)
+        self.input_formats = input_formats or DEFAULT_TIME_INPUT_FORMATS
+
+    def clean(self, value):
+        """
+        Validates that the input can be converted to a time. Returns a Python
+        datetime.time object.
+        """
+        super(TimeField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return None
+        if isinstance(value, datetime.time):
+            return value
+        for format in self.input_formats:
+            try:
+                return datetime.time(*time.strptime(value, format)[3:6])
+            except ValueError:
+                continue
+        raise ValidationError(self.error_messages['invalid'])
+
+DEFAULT_DATETIME_INPUT_FORMATS = (
+    '%Y-%m-%d %H:%M:%S',     # '2006-10-25 14:30:59'
+    '%Y-%m-%d %H:%M',        # '2006-10-25 14:30'
+    '%Y-%m-%d',              # '2006-10-25'
+    '%m/%d/%Y %H:%M:%S',     # '10/25/2006 14:30:59'
+    '%m/%d/%Y %H:%M',        # '10/25/2006 14:30'
+    '%m/%d/%Y',              # '10/25/2006'
+    '%m/%d/%y %H:%M:%S',     # '10/25/06 14:30:59'
+    '%m/%d/%y %H:%M',        # '10/25/06 14:30'
+    '%m/%d/%y',              # '10/25/06'
+)
+
+class DateTimeField(Field):
+    widget = DateTimeInput
+    default_error_messages = {
+        'invalid': _(u'Enter a valid date/time.'),
+    }
+
+    def __init__(self, input_formats=None, *args, **kwargs):
+        super(DateTimeField, self).__init__(*args, **kwargs)
+        self.input_formats = input_formats or DEFAULT_DATETIME_INPUT_FORMATS
+
+    def clean(self, value):
+        """
+        Validates that the input can be converted to a datetime. Returns a
+        Python datetime.datetime object.
+        """
+        super(DateTimeField, self).clean(value)
+        if value in EMPTY_VALUES:
+            return None
+        if isinstance(value, datetime.datetime):
+            return value
+        if isinstance(value, datetime.date):
+            return datetime.datetime(value.year, value.month, value.day)
+        if isinstance(value, list):
+            # Input comes from a SplitDateTimeWidget, for example. So, it's two
+            # components: date and time.
+            if len(value) != 2:
+                raise ValidationError(self.error_messages['invalid'])
+            value = '%s %s' % tuple(value)
+        for format in self.input_formats:
+            try:
+                return datetime.datetime(*time.strptime(value, format)[:6])
+            except ValueError:
+                continue
+        raise ValidationError(self.error_messages['invalid'])
+
+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)
+        if isinstance(regex, basestring):
+            regex = re.compile(regex)
+        self.regex = regex
+
+    def clean(self, value):
+        """
+        Validates that the input matches the regular expression. Returns a
+        Unicode object.
+        """
+        value = super(RegexField, self).clean(value)
+        if value == u'':
+            return value
+        if not self.regex.search(value):
+            raise ValidationError(self.error_messages['invalid'])
+        return value
+
+email_re = re.compile(
+    r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*"  # dot-atom
+    r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-011\013\014\016-\177])*"' # quoted-string
+    r')@(?:[A-Z0-9-]+\.)+[A-Z]{2,6}$', re.IGNORECASE)  # domain
+
+class EmailField(RegexField):
+    default_error_messages = {
+        'invalid': _(u'Enter a valid e-mail address.'),
+    }
+
+    def __init__(self, max_length=None, min_length=None, *args, **kwargs):
+        RegexField.__init__(self, email_re, max_length, min_length, *args,
+                            **kwargs)
+
+try:
+    from django.conf import settings
+    URL_VALIDATOR_USER_AGENT = settings.URL_VALIDATOR_USER_AGENT
+except ImportError:
+    # It's OK if Django settings aren't configured.
+    URL_VALIDATOR_USER_AGENT = 'Django (http://www.djangoproject.com/)'
+
+
+class FileField(Field):
+    widget = FileInput
+    default_error_messages = {
+        'invalid': _(u"No file was submitted. Check the encoding type on the form."),
+        'missing': _(u"No file was submitted."),
+        'empty': _(u"The submitted file is empty."),
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(FileField, self).__init__(*args, **kwargs)
+
+    def clean(self, data, initial=None):
+        super(FileField, self).clean(initial or data)
+        if not self.required and data in EMPTY_VALUES:
+            return None
+        elif not data and initial:
+            return initial
+
+        # 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'])
+
+        if not file_name:
+            raise ValidationError(self.error_messages['invalid'])
+        if not file_size:
+            raise ValidationError(self.error_messages['empty'])
+
+        return data
+
+class ImageField(FileField):
+    default_error_messages = {
+        'invalid_image': _(u"Upload a valid image. The file you uploaded was either not an image or a corrupted image."),
+    }
+
+    def clean(self, data, initial=None):
+        """
+        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).clean(data, initial)
+        if f is None:
+            return None
+        elif not data and initial:
+            return initial
+        from PIL import Image
+
+        # We need to get a file object for PIL. 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 = StringIO(data.read())
+            else:
+                file = StringIO(data['content'])
+
+        try:
+            # load() is the only method that can spot a truncated JPEG,
+            #  but it cannot be called sanely after verify()
+            trial_image = Image.open(file)
+            trial_image.load()
+
+            # Since we're about to use the file again we have to reset the
+            # file object if possible.
+            if hasattr(file, 'reset'):
+                file.reset()
+
+            # verify() is the only method that can spot a corrupt PNG,
+            #  but it must be called immediately after the constructor
+            trial_image = Image.open(file)
+            trial_image.verify()
+        except ImportError:
+            # Under PyPy, it is possible to import PIL. However, the underlying
+            # _imaging C module isn't available, so an ImportError will be
+            # raised. Catch and re-raise.
+            raise
+        except Exception: # Python Imaging Library doesn't recognize it as an image
+            raise ValidationError(self.error_messages['invalid_image'])
+        if hasattr(f, 'seek') and callable(f.seek):
+            f.seek(0)
+        return f
+
+url_re = re.compile(
+    r'^https?://' # http:// or https://
+    r'(?:(?:[A-Z0-9-]+\.)+[A-Z]{2,6}|' #domain...
+    r'localhost|' #localhost...
+    r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' # ...or ip
+    r'(?::\d+)?' # optional port
+    r'(?:/?|/\S+)$', re.IGNORECASE)
+
+class URLField(RegexField):
+    default_error_messages = {
+        'invalid': _(u'Enter a valid URL.'),
+        'invalid_link': _(u'This URL appears to be a broken link.'),
+    }
+
+    def __init__(self, max_length=None, min_length=None, verify_exists=False,
+            validator_user_agent=URL_VALIDATOR_USER_AGENT, *args, **kwargs):
+        super(URLField, self).__init__(url_re, max_length, min_length, *args,
+                                       **kwargs)
+        self.verify_exists = verify_exists
+        self.user_agent = validator_user_agent
+
+    def clean(self, value):
+        # If no URL scheme given, assume http://
+        if value and '://' not in value:
+            value = u'http://%s' % value
+        # If no URL path given, assume /
+        if value and not urlparse.urlsplit(value)[2]:
+            value += '/'
+        value = super(URLField, self).clean(value)
+        if value == u'':
+            return value
+        if self.verify_exists:
+            import urllib2
+            headers = {
+                "Accept": "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5",
+                "Accept-Language": "en-us,en;q=0.5",
+                "Accept-Charset": "ISO-8859-1,utf-8;q=0.7,*;q=0.7",
+                "Connection": "close",
+                "User-Agent": self.user_agent,
+            }
+            try:
+                req = urllib2.Request(value, None, headers)
+                u = urllib2.urlopen(req)
+            except ValueError:
+                raise ValidationError(self.error_messages['invalid'])
+            except: # urllib2.URLError, httplib.InvalidURL, etc.
+                raise ValidationError(self.error_messages['invalid_link'])
+        return value
+
+class BooleanField(Field):
+    widget = CheckboxInput
+
+    def clean(self, value):
+        """Returns a Python boolean object."""
+        # Explicitly check for the string 'False', which is what a hidden field
+        # will submit for False. Because bool("True") == True, we don't need to
+        # handle that explicitly.
+        if value == 'False':
+            value = False
+        else:
+            value = bool(value)
+        super(BooleanField, self).clean(value)
+        if not value and self.required:
+            raise ValidationError(self.error_messages['required'])
+        return value
+
+class NullBooleanField(BooleanField):
+    """
+    A field whose valid values are None, True and False. Invalid values are
+    cleaned to None.
+    """
+    widget = NullBooleanSelect
+
+    def clean(self, value):
+        """
+        Explicitly checks for the string 'True' and 'False', which is what a
+        hidden field will submit for True and False. Unlike the
+        Booleanfield we also need to check for True, because we are not using
+        the bool() function
+        """
+        if value in (True, 'True'):
+            return True
+        elif value in (False, 'False'):
+            return False
+        else:
+            return None
+
+class ChoiceField(Field):
+    widget = Select
+    default_error_messages = {
+        'invalid_choice': _(u'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=None, *args, **kwargs):
+        super(ChoiceField, self).__init__(required, widget, label, initial,
+                                          help_text, *args, **kwargs)
+        self.choices = choices
+
+    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 clean(self, value):
+        """
+        Validates that the input is in self.choices.
+        """
+        value = super(ChoiceField, self).clean(value)
+        if value in EMPTY_VALUES:
+            value = u''
+        value = smart_unicode(value)
+        if value == u'':
+            return value
+        if not self.valid_value(value):
+            raise ValidationError(self.error_messages['invalid_choice'] % {'value': value})
+        return value
+
+    def valid_value(self, value):
+        "Check to see if the provided value is a valid choice"
+        for k, v in self.choices:
+            if type(v) in (tuple, list):
+                # This is an optgroup, so look inside the group for options
+                for k2, v2 in v:
+                    if value == smart_unicode(k2):
+                        return True
+            else:
+                if value == smart_unicode(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 clean(self, value):
+        """
+        Validate that the value is in self.choices and can be coerced to the
+        right type.
+        """
+        value = super(TypedChoiceField, self).clean(value)
+        if value == self.empty_value or value in EMPTY_VALUES:
+            return self.empty_value
+        
+        # Hack alert: This field is purpose-made to use with Field.to_python as
+        # a coercion function so that ModelForms with choices work. However,
+        # Django's Field.to_python raises django.core.exceptions.ValidationError,
+        # which is a *different* exception than
+        # django.forms.utils.ValidationError. So unfortunatly we need to catch
+        # both.
+        try:
+            value = self.coerce(value)
+        except (ValueError, TypeError, django.core.exceptions.ValidationError):
+            raise ValidationError(self.error_messages['invalid_choice'] % {'value': value})
+        return value
+
+class MultipleChoiceField(ChoiceField):
+    hidden_widget = MultipleHiddenInput
+    widget = SelectMultiple
+    default_error_messages = {
+        'invalid_choice': _(u'Select a valid choice. %(value)s is not one of the available choices.'),
+        'invalid_list': _(u'Enter a list of values.'),
+    }
+
+    def clean(self, value):
+        """
+        Validates that the input is a list or tuple.
+        """
+        if self.required and not value:
+            raise ValidationError(self.error_messages['required'])
+        elif not self.required and not value:
+            return []
+        if not isinstance(value, (list, tuple)):
+            raise ValidationError(self.error_messages['invalid_list'])
+        new_value = [smart_unicode(val) for val in value]
+        # Validate that each value in the value list is in self.choices.
+        for val in new_value:
+            if not self.valid_value(val):
+                raise ValidationError(self.error_messages['invalid_choice'] % {'value': val})
+        return new_value
+
+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': _(u'Enter a list of values.'),
+    }
+
+    def __init__(self, fields=(), *args, **kwargs):
+        super(MultiValueField, self).__init__(*args, **kwargs)
+        # Set 'required' to False on the individual fields, because the
+        # required validation will be handled by MultiValueField, not by those
+        # individual fields.
+        for f in fields:
+            f.required = False
+        self.fields = fields
+
+    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 = ErrorList()
+        if not value or isinstance(value, (list, tuple)):
+            if not value or not [v for v in value if v not in EMPTY_VALUES]:
+                if self.required:
+                    raise ValidationError(self.error_messages['required'])
+                else:
+                    return self.compress([])
+        else:
+            raise ValidationError(self.error_messages['invalid'])
+        for i, field in enumerate(self.fields):
+            try:
+                field_value = value[i]
+            except IndexError:
+                field_value = None
+            if self.required and field_value in EMPTY_VALUES:
+                raise ValidationError(self.error_messages['required'])
+            try:
+                clean_data.append(field.clean(field_value))
+            except ValidationError, 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.
+                errors.extend(e.messages)
+        if errors:
+            raise ValidationError(errors)
+        return self.compress(clean_data)
+
+    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.')
+
+class FilePathField(ChoiceField):
+    def __init__(self, path, match=None, recursive=False, required=True,
+                 widget=None, label=None, initial=None, help_text=None,
+                 *args, **kwargs):
+        self.path, self.match, self.recursive = path, match, recursive
+        super(FilePathField, self).__init__(choices=(), required=required,
+            widget=widget, label=label, initial=initial, help_text=help_text,
+            *args, **kwargs)
+        self.choices = []
+        if self.match is not None:
+            self.match_re = re.compile(self.match)
+        if recursive:
+            for root, dirs, files in os.walk(self.path):
+                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)))
+        else:
+            try:
+                for f in os.listdir(self.path):
+                    full_file = os.path.join(self.path, f)
+                    if os.path.isfile(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):
+    hidden_widget = SplitHiddenDateTimeWidget
+    default_error_messages = {
+        'invalid_date': _(u'Enter a valid date.'),
+        'invalid_time': _(u'Enter a valid time.'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        errors = self.default_error_messages.copy()
+        if 'error_messages' in kwargs:
+            errors.update(kwargs['error_messages'])
+        fields = (
+            DateField(error_messages={'invalid': errors['invalid_date']}),
+            TimeField(error_messages={'invalid': errors['invalid_time']}),
+        )
+        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 EMPTY_VALUES:
+                raise ValidationError(self.error_messages['invalid_date'])
+            if data_list[1] in EMPTY_VALUES:
+                raise ValidationError(self.error_messages['invalid_time'])
+            return datetime.datetime.combine(*data_list)
+        return None
+
+ipv4_re = re.compile(r'^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$')
+
+class IPAddressField(RegexField):
+    default_error_messages = {
+        'invalid': _(u'Enter a valid IPv4 address.'),
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(IPAddressField, self).__init__(ipv4_re, *args, **kwargs)
+
+slug_re = re.compile(r'^[-\w]+$')
+
+class SlugField(RegexField):
+    default_error_messages = {
+        'invalid': _(u"Enter a valid 'slug' consisting of letters, numbers,"
+                     u" underscores or hyphens."),
+    }
+
+    def __init__(self, *args, **kwargs):
+        super(SlugField, self).__init__(slug_re, *args, **kwargs)