marshmallow

Features:

• Add Schema.validate method which validates input data against a schema. Similar to Schema.load, but does not call make_object and only returns the errors dictionary.

• Add several validation functions to the validate module. Thanks philtay.

• Store field name and instance on exceptions raised in strict mode.

Bug fixes:

• Fix serializing dictionaries when field names are methods of dict (e.g. "items"). Thanks rozenm for reporting.

• If a Nested field is passed many=True, None serializes to an empty list. Thanks nickretallack for reporting.

• Fix behavior of many argument passed to dump and load. Thanks svenstaro for reporting and helping with this.

• Fix skip_missing behavior for String and List fields. Thanks malexer for reporting.

• Fix compatibility with python-dateutil 2.3.

• More consistent error messages across DateTime, TimeDelta, Date, and Time fields.

Support:

• Update Flask and Peewee examples.

Hotfix release.

• Ensure that errors dictionary is correctly cleared on each call to Schema.dump and Schema.load.

Adds new features, speed improvements, better error handling, and updated documentation.

• Add skip_missing class Meta option.

• A field's default may be a callable.

• Allow accessor function to be configured via the Schema.accessor decorator or the __accessor__ class member.

• URL and Email fields are validated upon serialization.

• dump and load can receive the many argument.

• Move a number of utility functions from fields.py to utils.py.

• More useful repr for Field classes.

• If a field's default is fields.missing and its serialized value is None, it will not be included in the final serialized result.

• Schema.dumps no longer coerces its result to a binary string on Python 3.

• Backwards-incompatible: Schema output is no longer an OrderedDict by default. If you want ordered field output, you must explicitly set the ordered option to True.

• Backwards-incompatible: error parameter of the Field constructor is deprecated. Raise a ValidationError instead.

• Expanded test coverage.

• Updated docs.

Major reworking and simplification of the public API, centered around support for deserialization, improved validation, and a less stateful Schema class.

• Rename Serializer to Schema.

• Support for deserialization.

• Use the Schema.dump and Schema.load methods for serializing and deserializing, respectively.

• Backwards-incompatible: Remove Serializer.json and Serializer.to_json. Use Schema.dumps instead.

• Reworked fields interface.

• Backwards-incompatible: Field classes implement _serialize and _deserialize methods. serialize and deserialize comprise the public API for a Field. Field.format and Field.output have been removed.

• Add exceptions.ForcedError which allows errors to be raised during serialization (instead of storing errors in the errors dict).

• Backwards-incompatible: DateTime field serializes to ISO8601 format by default (instead of RFC822).

• Backwards-incompatible: Remove Serializer.factory method. It is no longer necessary with the dump method.

• Backwards-incompatible: Allow nesting a serializer within itself recursively. Use exclude or only to prevent infinite recursion.

• Backwards-incompatible: Multiple errors can be stored for a single field. The errors dictionary returned by load and dump have lists of error messages keyed by field name.

• Remove validated decorator. Validation occurs within Field methods.

• Function field raises a ValueError if an uncallable object is passed to its constructor.

• Nested fields inherit context from their parent.

• Add Schema.preprocessor and Schema.validator decorators for registering preprocessing and schema-level validation functions respectively.

• Custom error messages can be specified by raising a ValidationError within a validation function.

• Extra keyword arguments passed to a Field are stored as metadata.

• Fix ordering of field output.

• Fix behavior of the required parameter on Nested fields.

• Fix serializing keyed tuple types (e.g. namedtuple) with class Meta options.

• Fix default value for Fixed and Price fields.

• Fix serialization of binary strings.

• Schemas can inherit fields from non-Schema base classes (e.g. mixins). Also, fields are inherited according to the MRO (rather than recursing over base classes). Thanks jmcarp.

• Add Str, Bool, and Int field class aliases.

• Add Serializer.error_handler decorator that registers a custom error handler.

• Add Serializer.data_handler decorator that registers data post-processing callbacks.

• Backwards-incompatible: process_data method is deprecated. Use the data_handler decorator instead.

• Fix bug that raised error when passing extra data together with many=True. Thanks buttsicles for reporting.

• If required=True validation is violated for a given Field, it will raise an error message that is different from the message specified by the error argument. Thanks asteinlein.

• More generic error message raised when required field is missing.

• validated decorator should only wrap a Field class's output method.

• Fix bug in serializing keyed tuple types, e.g. namedtuple and KeyedTuple.

• Nested field can load a serializer by its class name as a string. This makes it easier to implement 2-way nesting.

• Make Serializer.data override-able.

• Add Serializer.factory for creating a factory function that returns a Serializer instance.

• MarshallingError stores its underlying exception as an instance variable. This is useful for inspecting errors.

• fields.Select is aliased to fields.Enum.

• Add fields.__all__ and marshmallow.__all__ so that the modules can be more easily extended.

• Expose Serializer.OPTIONS_CLASS as a class variable so that options defaults can be overridden.

• Add Serializer.process_data hook that allows subclasses to manipulate the final output data.

• Add json_module class Meta option.

• Add required option to fields . Thanks DeaconDesperado.

• Tested on Python 3.4 and PyPy.

• Fix Integer field default. It is now 0 instead of 0.0. Thanks kalasjocke.

• Add context param to Serializer. Allows accessing arbitrary objects in Function and Method fields.

• Function and Method fields raise MarshallingError if their argument is uncallable.

• Enable custom field validation via the validate parameter.

• Add utils.from_rfc for parsing RFC datestring to Python datetime object.

• Avoid unnecessary attribute access in utils.to_marshallable_type for improved performance.

• Fix RFC822 formatting for localized datetimes.

• Can customize validation error messages by passing the error parameter to a field.

• Backwards-incompatible: Rename fields.NumberField -> fields.Number.

• Add fields.Select. Thanks ecarreras.

• Support nesting a Serializer within itself by passing "self" into fields.Nested (only up to depth=1).

• Backwards-incompatible: No implicit serializing of collections. Must set many=True if serializing to a list. This ensures that marshmallow handles singular objects correctly, even if they are iterable.

• If Nested field only parameter is a field name, only return a single value for the nested object (instead of a dict) or a flat list of values.

• Improved performance and stability.

• An object's __marshallable__ method, if defined, takes precedence over __getitem__.

• Generator expressions can be passed to a serializer.

• Better support for serializing list-like collections (e.g. ORM querysets).

• Other minor bugfixes.

• Add additional class Meta option.

• Add dateformat class Meta option.

• Support for serializing UUID, date, time, and timedelta objects.

• Remove Serializer.to_data method. Just use Serialize.data property.

• String field defaults to empty string instead of None.

• Backwards-incompatible: isoformat and rfcformat functions moved to utils.py.

• Backwards-incompatible: Validation functions moved to validate.py.

• Backwards-incompatible: Remove types.py.

• Reorder parameters to DateTime field (first parameter is dateformat).

• Ensure that to_json returns bytestrings.

• Fix bug with including an object property in fields Meta option.

• Fix bug with passing None to a serializer.

• Fix bug with serializing dictionaries.

• Fix error raised when serializing empty list.

• Add only and exclude parameters to Serializer constructor.

• Add strict parameter and option: causes Serializer to raise an error if invalid data are passed in, rather than storing errors.

• Updated Flask + SQLA example in docs.

• Declaring Serializers just got easier. The class Meta paradigm allows you to specify fields more concisely. Can specify fields and exclude options.

• Allow date formats to be changed by passing format parameter to DateTime field constructor. Can either be "rfc" (default), "iso", or a date format string.

• More useful error message when declaring fields as classes (instead of an instance, which is the correct usage).

• Rename MarshallingException -> MarshallingError.

• Rename marshmallow.core -> marshmallow.serializer.

• Allow prefixing field names.

• Fix storing errors on Nested Serializers.

• Python 2.6 support.

• Field-level validation.

• Add fields.Method.

• Add fields.Function.

• Allow binding of extra data to a serialized object by passing the extra param when initializing a Serializer.

• Add relative parameter to fields.Url that allows for relative URLs.

• First release.