Python 3.9 is now generally available.

google.appengine.api.validation.Optional

Definition of optional attributes.

Inherits From: Validator, expected_type

Optional values are attributes which can be set to None or left unset. All values in a basic Validated class are set to None at initialization. Failure to assign to non-optional values will result in a validation error when calling CheckInitialized.

validator Optional validation condition.

AttributeDefinitionError if validator is not callable.

Child Classes

class expected_type

Methods

CheckFieldInitialized

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Check for missing fields or conflicts between fields.

Default behavior performs a simple None-check, but this can be overridden. If the intent is to allow optional fields, then use the Optional validator instead.

Args
value Value to validate.
key Name of the field being validated.
obj The object to validate against.

Raises
ValidationError When there are missing or conflicting fields.

GetWarnings

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Return any warnings on this attribute.

Validates the value with an eye towards things that aren't fatal problems.

Args
value Value to validate.
key Name of the field being validated.
obj The object to validate against.

Returns
A list of tuples (context, warning) where

  • Context is the field (or dotted field path, if a sub-field)
  • Warning is the string warning text

ToValue

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Convert value to a simplified collection or basic type.

Validate

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Optionally require a value.

Normal validators do not accept None. This will accept None on behalf of the contained validator.

Args
value Value to be validated as optional.
key Name of the field being validated.

Returns
None if value is None, else results of contained validation.

__call__

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Main interface to validator is call mechanism.