class MultiValueField
from django.forms import MultiValueField
Aggregate 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.
Ancestors (MRO)
- MultiValueField
-
Field
Attributes
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Defined in |
default_error_messages = {'invalid': 'Enter a list of values.', 'incomplete': 'Enter a complete value.'}
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MultiValueField
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default_error_messages = {'required': 'This field is required.'}
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Field
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default_validators = []
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Field
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empty_values = [None, '', [], (), {}]
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Field
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Expand
Collapse
Methods
def
bound_data(self, data, initial):
Field
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.
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.
"""
if self.disabled:
return initial
return data
Validate 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]).
def clean(self, value):
"""
Validate 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 self.disabled and not isinstance(value, list):
value = self.widget.decompress(value)
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
Validate the given value and return its "cleaned" value as an
appropriate Python object. Raise ValidationError for any errors.
def clean(self, value):
"""
Validate the given value and return its "cleaned" value as an
appropriate Python object. Raise ValidationError for any errors.
"""
value = self.to_python(value)
self.validate(value)
self.run_validators(value)
return value
def
compress(self, data_list):
MultiValueField
Return 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.
def compress(self, data_list):
"""
Return 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
get_bound_field(self, form, field_name):
Field
Return a BoundField instance that will be used when accessing the form
field in a template.
def get_bound_field(self, form, field_name):
"""
Return a BoundField instance that will be used when accessing the form
field in a template.
"""
return BoundField(form, self, field_name)
def
has_changed(self, initial, data):
def has_changed(self, initial, data):
if self.disabled:
return False
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):
try:
initial = field.to_python(initial)
except ValidationError:
return True
if field.has_changed(initial, data):
return True
return False
Return True if data differs from initial.
def has_changed(self, initial, data):
"""Return True if data differs from initial."""
# Always return False if the field is disabled since self.bound_data
# always uses the initial value in this case.
if self.disabled:
return False
try:
data = self.to_python(data)
if hasattr(self, '_coerce'):
return self._coerce(data) != self._coerce(initial)
except ValidationError:
return True
# For purposes of seeing whether something has changed, None is
# the same as an empty string, if the data or initial value we get
# is None, replace it with ''.
initial_value = initial if initial is not None else ''
data_value = data if data is not None else ''
return initial_value != data_value
def
prepare_value(self, value):
Field
def prepare_value(self, value):
return value
def
run_validators(self, value):
Field
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
to_python(self, value):
Field
def to_python(self, value):
return value
def
validate(self, value):
def validate(self, value):
pass
def validate(self, value):
if value in self.empty_values and self.required:
raise ValidationError(self.error_messages['required'], code='required')
def
widget_attrs(self, widget):
Field
Given a Widget instance (*not* a Widget class), return a dictionary of
any HTML attributes that should be added to the Widget, based on this
Field.
def widget_attrs(self, widget):
"""
Given a Widget instance (*not* a Widget class), return a dictionary of
any HTML attributes that should be added to the Widget, based on this
Field.
"""
return {}