django-rest-framework/rest_framework/fields.py
2013-02-12 22:59:01 +00:00

687 lines
22 KiB
Python

from __future__ import unicode_literals
import copy
import datetime
import inspect
import re
import warnings
from django.core import validators
from django.core.exceptions import ValidationError
from django.conf import settings
from django import forms
from django.forms import widgets
from django.utils.encoding import is_protected_type
from django.utils.translation import ugettext_lazy as _
from rest_framework.compat import parse_date, parse_datetime
from rest_framework.compat import timezone
from rest_framework.compat import BytesIO
from rest_framework.compat import six
from rest_framework.compat import smart_text
def is_simple_callable(obj):
"""
True if the object is a callable that takes no arguments.
"""
return (
(inspect.isfunction(obj) and not inspect.getargspec(obj)[0]) or
(inspect.ismethod(obj) and len(inspect.getargspec(obj)[0]) <= 1)
)
def get_component(obj, attr_name):
"""
Given an object, and an attribute name,
return that attribute on the object.
"""
if isinstance(obj, dict):
val = obj[attr_name]
else:
val = getattr(obj, attr_name)
if is_simple_callable(val):
return val()
return val
class Field(object):
read_only = True
creation_counter = 0
empty = ''
type_name = None
partial = False
use_files = False
form_field_class = forms.CharField
def __init__(self, source=None):
self.parent = None
self.creation_counter = Field.creation_counter
Field.creation_counter += 1
self.source = source
def initialize(self, parent, field_name):
"""
Called to set up a field prior to field_to_native or field_from_native.
parent - The parent serializer.
model_field - The model field this field corresponds to, if one exists.
"""
self.parent = parent
self.root = parent.root or parent
self.context = self.root.context
self.partial = self.root.partial
if self.partial:
self.required = False
def field_from_native(self, data, files, field_name, into):
"""
Given a dictionary and a field name, updates the dictionary `into`,
with the field and it's deserialized value.
"""
return
def field_to_native(self, obj, field_name):
"""
Given and object and a field name, returns the value that should be
serialized for that field.
"""
if obj is None:
return self.empty
if self.source == '*':
return self.to_native(obj)
source = self.source or field_name
value = obj
for component in source.split('.'):
value = get_component(value, component)
if value is None:
break
return self.to_native(value)
def to_native(self, value):
"""
Converts the field's value into it's simple representation.
"""
if is_simple_callable(value):
value = value()
if is_protected_type(value):
return value
elif hasattr(value, '__iter__') and not isinstance(value, (dict, six.string_types)):
return [self.to_native(item) for item in value]
elif isinstance(value, dict):
return dict(map(self.to_native, (k, v)) for k, v in value.items())
return smart_text(value)
def attributes(self):
"""
Returns a dictionary of attributes to be used when serializing to xml.
"""
if self.type_name:
return {'type': self.type_name}
return {}
class WritableField(Field):
"""
Base for read/write fields.
"""
default_validators = []
default_error_messages = {
'required': _('This field is required.'),
'invalid': _('Invalid value.'),
}
widget = widgets.TextInput
default = None
def __init__(self, source=None, read_only=False, required=None,
validators=[], error_messages=None, widget=None,
default=None, blank=None):
# 'blank' is to be deprecated in favor of 'required'
if blank is not None:
warnings.warn('The `blank` keyword argument is due to deprecated. '
'Use the `required` keyword argument instead.',
PendingDeprecationWarning, stacklevel=2)
required = not(blank)
super(WritableField, self).__init__(source=source)
self.read_only = read_only
if required is None:
self.required = not(read_only)
else:
assert not (read_only and required), "Cannot set required=True and read_only=True"
self.required = required
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
self.default = default if default is not None else self.default
# Widgets are ony used for HTML forms.
widget = widget or self.widget
if isinstance(widget, type):
widget = widget()
self.widget = widget
def validate(self, value):
if value in validators.EMPTY_VALUES and self.required:
raise ValidationError(self.error_messages['required'])
def run_validators(self, value):
if value in validators.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:
message = self.error_messages[e.code]
if e.params:
message = message % e.params
errors.append(message)
else:
errors.extend(e.messages)
if errors:
raise ValidationError(errors)
def field_from_native(self, data, files, field_name, into):
"""
Given a dictionary and a field name, updates the dictionary `into`,
with the field and it's deserialized value.
"""
if self.read_only:
return
try:
if self.use_files:
files = files or {}
native = files[field_name]
else:
native = data[field_name]
except KeyError:
if self.default is not None and not self.partial:
# Note: partial updates shouldn't set defaults
native = self.default
else:
if self.required:
raise ValidationError(self.error_messages['required'])
return
value = self.from_native(native)
if self.source == '*':
if value:
into.update(value)
else:
self.validate(value)
self.run_validators(value)
into[self.source or field_name] = value
def from_native(self, value):
"""
Reverts a simple representation back to the field's value.
"""
return value
class ModelField(WritableField):
"""
A generic field that can be used against an arbitrary model field.
"""
def __init__(self, *args, **kwargs):
try:
self.model_field = kwargs.pop('model_field')
except KeyError:
raise ValueError("ModelField requires 'model_field' kwarg")
self.min_length = kwargs.pop('min_length',
getattr(self.model_field, 'min_length', None))
self.max_length = kwargs.pop('max_length',
getattr(self.model_field, 'max_length', None))
super(ModelField, self).__init__(*args, **kwargs)
if self.min_length is not None:
self.validators.append(validators.MinLengthValidator(self.min_length))
if self.max_length is not None:
self.validators.append(validators.MaxLengthValidator(self.max_length))
def from_native(self, value):
rel = getattr(self.model_field, "rel", None)
if rel is not None:
return rel.to._meta.get_field(rel.field_name).to_python(value)
else:
return self.model_field.to_python(value)
def field_to_native(self, obj, field_name):
value = self.model_field._get_val_from_obj(obj)
if is_protected_type(value):
return value
return self.model_field.value_to_string(obj)
def attributes(self):
return {
"type": self.model_field.get_internal_type()
}
##### Typed Fields #####
class BooleanField(WritableField):
type_name = 'BooleanField'
form_field_class = forms.BooleanField
widget = widgets.CheckboxInput
default_error_messages = {
'invalid': _("'%s' value must be either True or False."),
}
empty = False
# Note: we set default to `False` in order to fill in missing value not
# supplied by html form. TODO: Fix so that only html form input gets
# this behavior.
default = False
def from_native(self, value):
if value in ('true', 't', 'True', '1'):
return True
if value in ('false', 'f', 'False', '0'):
return False
return bool(value)
class CharField(WritableField):
type_name = 'CharField'
form_field_class = forms.CharField
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(min_length))
if max_length is not None:
self.validators.append(validators.MaxLengthValidator(max_length))
def from_native(self, value):
if isinstance(value, six.string_types) or value is None:
return value
return smart_text(value)
class URLField(CharField):
type_name = 'URLField'
def __init__(self, **kwargs):
kwargs['max_length'] = kwargs.get('max_length', 200)
kwargs['validators'] = [validators.URLValidator()]
super(URLField, self).__init__(**kwargs)
class SlugField(CharField):
type_name = 'SlugField'
def __init__(self, *args, **kwargs):
kwargs['max_length'] = kwargs.get('max_length', 50)
super(SlugField, self).__init__(*args, **kwargs)
class ChoiceField(WritableField):
type_name = 'ChoiceField'
form_field_class = forms.ChoiceField
widget = widgets.Select
default_error_messages = {
'invalid_choice': _('Select a valid choice. %(value)s is not one of '
'the available choices.'),
}
def __init__(self, choices=(), *args, **kwargs):
super(ChoiceField, self).__init__(*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 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'] % {'value': value})
def valid_value(self, value):
"""
Check to see if the provided value is a valid choice.
"""
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 == smart_text(k2):
return True
else:
if value == smart_text(k) or value == k:
return True
return False
class EmailField(CharField):
type_name = 'EmailField'
form_field_class = forms.EmailField
default_error_messages = {
'invalid': _('Enter a valid e-mail address.'),
}
default_validators = [validators.validate_email]
def from_native(self, value):
ret = super(EmailField, self).from_native(value)
if ret is None:
return None
return ret.strip()
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 RegexField(CharField):
type_name = 'RegexField'
form_field_class = forms.RegexField
def __init__(self, regex, max_length=None, min_length=None, *args, **kwargs):
super(RegexField, self).__init__(max_length, min_length, *args, **kwargs)
self.regex = regex
def _get_regex(self):
return self._regex
def _set_regex(self, regex):
if isinstance(regex, six.string_types):
regex = re.compile(regex)
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)
def __deepcopy__(self, memo):
result = copy.copy(self)
memo[id(self)] = result
result.validators = self.validators[:]
return result
class DateField(WritableField):
type_name = 'DateField'
widget = widgets.DateInput
form_field_class = forms.DateField
default_error_messages = {
'invalid': _("'%s' value has an invalid date format. It must be "
"in YYYY-MM-DD format."),
'invalid_date': _("'%s' value has the correct format (YYYY-MM-DD) "
"but it is an invalid date."),
}
empty = None
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
if isinstance(value, datetime.datetime):
if timezone and settings.USE_TZ and timezone.is_aware(value):
# Convert aware datetimes to the default time zone
# before casting them to dates (#17742).
default_timezone = timezone.get_default_timezone()
value = timezone.make_naive(value, default_timezone)
return value.date()
if isinstance(value, datetime.date):
return value
try:
parsed = parse_date(value)
if parsed is not None:
return parsed
except ValueError:
msg = self.error_messages['invalid_date'] % value
raise ValidationError(msg)
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class DateTimeField(WritableField):
type_name = 'DateTimeField'
widget = widgets.DateTimeInput
form_field_class = forms.DateTimeField
default_error_messages = {
'invalid': _("'%s' value has an invalid format. It must be in "
"YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format."),
'invalid_date': _("'%s' value has the correct format "
"(YYYY-MM-DD) but it is an invalid date."),
'invalid_datetime': _("'%s' value has the correct format "
"(YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ]) "
"but it is an invalid date/time."),
}
empty = None
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
if isinstance(value, datetime.datetime):
return value
if isinstance(value, datetime.date):
value = datetime.datetime(value.year, value.month, value.day)
if settings.USE_TZ:
# For backwards compatibility, interpret naive datetimes in
# local time. This won't work during DST change, but we can't
# do much about it, so we let the exceptions percolate up the
# call stack.
warnings.warn("DateTimeField received a naive datetime (%s)"
" while time zone support is active." % value,
RuntimeWarning)
default_timezone = timezone.get_default_timezone()
value = timezone.make_aware(value, default_timezone)
return value
try:
parsed = parse_datetime(value)
if parsed is not None:
return parsed
except ValueError:
msg = self.error_messages['invalid_datetime'] % value
raise ValidationError(msg)
try:
parsed = parse_date(value)
if parsed is not None:
return datetime.datetime(parsed.year, parsed.month, parsed.day)
except ValueError:
msg = self.error_messages['invalid_date'] % value
raise ValidationError(msg)
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class IntegerField(WritableField):
type_name = 'IntegerField'
form_field_class = forms.IntegerField
default_error_messages = {
'invalid': _('Enter a whole number.'),
'max_value': _('Ensure this value is less than or equal to %(limit_value)s.'),
'min_value': _('Ensure this value is greater than or equal to %(limit_value)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)
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 from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
try:
value = int(str(value))
except (ValueError, TypeError):
raise ValidationError(self.error_messages['invalid'])
return value
class FloatField(WritableField):
type_name = 'FloatField'
form_field_class = forms.FloatField
default_error_messages = {
'invalid': _("'%s' value must be a float."),
}
def from_native(self, value):
if value in validators.EMPTY_VALUES:
return None
try:
return float(value)
except (TypeError, ValueError):
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
class FileField(WritableField):
use_files = True
type_name = 'FileField'
form_field_class = forms.FileField
widget = widgets.FileInput
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': _('Ensure this filename has at most %(max)d characters (it has %(length)d).'),
'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 from_native(self, data):
if data in validators.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'])
if self.max_length is not None and len(file_name) > self.max_length:
error_values = {'max': self.max_length, 'length': len(file_name)}
raise ValidationError(self.error_messages['max_length'] % error_values)
if not file_name:
raise ValidationError(self.error_messages['invalid'])
if not self.allow_empty_file and not file_size:
raise ValidationError(self.error_messages['empty'])
return data
def to_native(self, value):
return value.name
class ImageField(FileField):
use_files = True
form_field_class = forms.ImageField
default_error_messages = {
'invalid_image': _("Upload a valid image. The file you uploaded was "
"either not an image or a corrupted image."),
}
def from_native(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).from_native(data)
if f is None:
return None
from compat import Image
assert Image is not None, 'PIL must be installed for ImageField support'
# 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 = 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 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
class SerializerMethodField(Field):
"""
A field that gets its value by calling a method on the serializer it's attached to.
"""
def __init__(self, method_name):
self.method_name = method_name
super(SerializerMethodField, self).__init__()
def field_to_native(self, obj, field_name):
value = getattr(self.parent, self.method_name)(obj)
return self.to_native(value)