marshmallow: simplified object serialization

marshmallow is an ORM/ODM/framework-agnostic library for converting complex datatypes, such as objects, to and from native Python datatypes.

``` {.sourceCode .python} from datetime import date from marshmallow import Schema, fields, pprint

class ArtistSchema(Schema): name = fields.Str()

class AlbumSchema(Schema): title = fields.Str() release_date = fields.Date() artist = fields.Nested(ArtistSchema())

bowie = dict(name=’David Bowie’) album = dict(artist=bowie, title=’Hunky Dory’, release_date=date(1971, 12, 17))

schema = AlbumSchema() result = schema.dump(album) pprint(result.data, indent=2)

{ ‘artist’: {‘name’: ‘David Bowie’},

‘release_date’: ‘1971-12-17’,

‘title’: ‘Hunky Dory’}

```

In short, marshmallow schemas can be used to:

• Validate input data.
• Deserialize input data to app-level objects.
• Serialize app-level objects to primitive Python types. The serialized objects can then be rendered to standard formats such as JSON for use in an HTTP API.

Get It Now

$ pip install -U marshmallow

Documentation

Full documentation is available at http://marshmallow.readthedocs.io/ .

Requirements

• Python >= 2.6 or >= 3.3

marshmallow has no external dependencies outside of the Python standard library, although python-dateutil is recommended for robust datetime deserialization.

Ecosystem

A list of marshmallow-related libraries can be found at the GitHub wiki here:

https://github.com/marshmallow-code/marshmallow/wiki/Ecosystem

Project Links

• Docs: http://marshmallow.readthedocs.io/
• Changelog: http://marshmallow.readthedocs.io/en/latest/changelog.html
• PyPI: https://pypi.python.org/pypi/marshmallow
• Issues: https://github.com/marshmallow-code/marshmallow/issues

License

MIT licensed. See the bundled LICENSE file for more details.

Changelog

2.9.1 (2016-07-21)

Bug fixes:

• Fix serialization of datetime.time objects with microseconds (464{.interpreted-text role=”issue”}). Thanks Tim-Erwin{.interpreted-text role=”user”} for reporting and thanks vuonghv{.interpreted-text role=”user”} for the fix.
• Make @validates consistent with field validator behavior: if validation fails, the field will not be included in the deserialized output (391{.interpreted-text role=”issue”}). Thanks martinstein{.interpreted-text role=”user”} for reporting and thanks @vuonghv{.interpreted-text role=”user”} for the fix.

2.9.0 (2016-07-06)

• Decimal field coerces input values to a string before deserializing to a [decimal.Decimal]{.title-ref} object in order to avoid transformation of float values under 12 significant digits (434{.interpreted-text role=”issue”}, 435{.interpreted-text role=”issue”}). Thanks davidthornton{.interpreted-text role=”user”} for the PR.

2.8.0 (2016-06-23)

Features:

• Allow only and exclude parameters to take nested fields, using dot-delimited syntax (e.g. only=['blog.author.email']) (402{.interpreted-text role=”issue”}). Thanks Tim-Erwin{.interpreted-text role=”user”} and deckar01{.interpreted-text role=”user”} for the discussion and implementation.

Support:

• Update tasks.py for compatibility with invoke>=0.13.0. Thanks deckar01{.interpreted-text role=”user”}.

2.7.3 (2016-05-05)

• Make field.parent and field.name accessible to on_bind_field (449{.interpreted-text role=”issue”}). Thanks immerrr{.interpreted-text role=”user”}.

2.7.2 (2016-04-27)

No code changes in this release. This is a reupload in order to distribute an sdist for the last hotfix release. See 443{.interpreted-text role=”issue”}.

Support:

• Update license entry in setup.py to fix RPM distributions (433{.interpreted-text role=”issue”}). Thanks rrajaravi{.interpreted-text role=”user”} for reporting.

2.7.1 (2016-04-08)

Bug fixes:

• Only add Schemas to class registry if a class name is provided. This allows Schemas to be constructed dynamically using the type constructor without getting added to the class registry (which is useful for saving memory).

2.7.0 (2016-04-04)

Features:

• Make context available to Nested field's on_bind_field method (408{.interpreted-text role=”issue”}). Thanks immerrr{.interpreted-text role=”user”} for the PR.
• Pass through user ValidationError kwargs (418{.interpreted-text role=”issue”}). Thanks russelldavies{.interpreted-text role=”user”} for helping implement this.

Other changes:

• Remove unused attributes root, parent, and name from SchemaABC (410{.interpreted-text role=”issue”}). Thanks Tim-Erwin{.interpreted-text role=”user”} for the PR.

2.6.1 (2016-03-17)

Bug fixes:

• Respect [load_from]{.title-ref} when reporting errors for nested required fields (414{.interpreted-text role=”issue”}). Thanks yumike{.interpreted-text role=”user”}.

2.6.0 (2016-02-01)

Features:

• Add partial argument to Schema.validate (379{.interpreted-text role=”issue”}). Thanks tdevelioglu{.interpreted-text role=”user”} for the PR.
• Add equal argument to validate.Length. Thanks daniloakamine{.interpreted-text role=”user”}.
• Collect all validation errors for each item deserialized by a List field (345{.interpreted-text role=”issue”}). Thanks maximkulkin{.interpreted-text role=”user”} for the report and the PR.

2.5.0 (2016-01-16)

Features:

• Allow a tuple of field names to be passed as the partial argument to Schema.load (369{.interpreted-text role=”issue”}). Thanks tdevelioglu{.interpreted-text role=”user”} for the PR.
• Add schemes argument to validate.URL (356{.interpreted-text role=”issue”}).

2.4.2 (2015-12-08)

Bug fixes:

• Prevent duplicate error messages when validating nested collections (360{.interpreted-text role=”issue”}). Thanks alexmorken{.interpreted-text role=”user”} for the catch and patch.

2.4.1 (2015-12-07)

Bug fixes:

• Serializing an iterator will not drop the first item (343{.interpreted-text role=”issue”}, 353{.interpreted-text role=”issue”}). Thanks jmcarp{.interpreted-text role=”user”} for the patch. Thanks edgarallang{.interpreted-text role=”user”} and jmcarp{.interpreted-text role=”user”} for reporting.

2.4.0 (2015-12-06)

Features:

• Add skip_on_field_errors parameter to validates_schema (323{.interpreted-text role=”issue”}). Thanks jjvattamattom{.interpreted-text role=”user”} for the suggestion and d-sutherland{.interpreted-text role=”user”} for the PR.

Bug fixes:

• Fix FormattedString serialization (348{.interpreted-text role=”issue”}). Thanks acaird{.interpreted-text role=”user”} for reporting.
• Fix @validates behavior when used when attribute is specified and strict=True (350{.interpreted-text role=”issue”}). Thanks density{.interpreted-text role=”user”} for reporting.

2.3.0 (2015-11-22)

Features:

• Add dump_to parameter to fields (310{.interpreted-text role=”issue”}). Thanks ShayanArmanPercolate{.interpreted-text role=”user”} for the suggestion. Thanks franciscod{.interpreted-text role=”user”} and ewang{.interpreted-text role=”user”} for the PRs.
• The deserialize function passed to fields.Function can optionally receive a context argument (324{.interpreted-text role=”issue”}). Thanks DamianHeard{.interpreted-text role=”user”}.
• The serialize function passed to fields.Function is optional (325{.interpreted-text role=”issue”}). Thanks again DamianHeard{.interpreted-text role=”user”}.
• The serialize function passed to fields.Method is optional (329{.interpreted-text role=”issue”}). Thanks justanr{.interpreted-text role=”user”}.

Deprecation/Removal:

• The func argument of fields.Function has been renamed to serialize.
• The method_name argument of fields.Method has been renamed to serialize.

func and method_name are still present for backwards-compatibility, but they will both be removed in marshmallow 3.0.

2.2.1 (2015-11-11)

Bug fixes:

• Skip field validators for fields that aren't included in only (320{.interpreted-text role=”issue”}). Thanks carlos-alberto{.interpreted-text role=”user”} for reporting and eprikazc{.interpreted-text role=”user”} for the PR.

2.2.0 (2015-10-26)

Features:

• Add support for partial deserialization with the partial argument to Schema and Schema.load (290{.interpreted-text role=”issue”}). Thanks taion{.interpreted-text role=”user”}.

Deprecation/Removals:

• Query and QuerySelect fields are removed.
• Passing of strings to required and allow_none is removed. Pass the error_messages argument instead.

Support:

• Add example of Schema inheritance in docs (225{.interpreted-text role=”issue”}). Thanks martinstein{.interpreted-text role=”user”} for the suggestion and juanrossi{.interpreted-text role=”user”} for the PR.
• Add "Customizing Error Messages" section to custom fields docs.

2.1.3 (2015-10-18)

Bug fixes:

• Fix serialization of collections for which [iter]{.title-ref} will modify position, e.g. Pymongo cursors (303{.interpreted-text role=”issue”}). Thanks Mise{.interpreted-text role=”user”} for the catch and patch.

2.1.2 (2015-10-14)

Bug fixes:

• Fix passing data to schema validator when using @validates_schema(many=True) (297{.interpreted-text role=”issue”}). Thanks d-sutherland{.interpreted-text role=”user”} for reporting.
• Fix usage of @validates with a nested field when many=True (298{.interpreted-text role=”issue”}). Thanks nelfin{.interpreted-text role=”user”} for the catch and patch.

2.1.1 (2015-10-07)

Bug fixes:

• Constant field deserializes to its value regardless of whether its field name is present in input data (291{.interpreted-text role=”issue”}). Thanks fayazkhan{.interpreted-text role=”user”} for reporting.

2.1.0 (2015-09-30)

Features:

• Add Dict field for arbitrary mapping data (251{.interpreted-text role=”issue”}). Thanks dwieeb{.interpreted-text role=”user”} for adding this and Dowwie{.interpreted-text role=”user”} for the suggestion.
• Add Field.root property, which references the field's Schema.

Deprecation/Removals:

• The extra param of Schema is deprecated. Add extra data in a post_load method instead.
• UnmarshallingError and MarshallingError are removed.

Bug fixes:

• Fix storing multiple schema-level validation errors (287{.interpreted-text role=”issue”}). Thanks evgeny-sureev{.interpreted-text role=”user”} for the patch.
• If missing=None on a field, allow_none will be set to True.

Other changes:

• A List's inner field will have the list field set as its parent. Use root to access the Schema.

2.0.0 (2015-09-25)

Features:

• Make error messages configurable at the class level and instance level (Field.default_error_messages attribute and error_messages parameter, respectively).

Deprecation/Removals:

• Remove make_object. Use a post_load method instead (277{.interpreted-text role=”issue”}).
• Remove the error parameter and attribute of Field.
• Passing string arguments to required and allow_none is deprecated. Pass the error_messages argument instead. This API will be removed in version 2.2.
• Remove Arbitrary, Fixed, and Price fields (86{.interpreted-text role=”issue”}). Use Decimal instead.
• Remove Select / Enum fields (135{.interpreted-text role=”issue”}). Use the OneOf validator instead.

Bug fixes:

• Fix error format for Nested fields when many=True. Thanks alexmorken{.interpreted-text role=”user”}.
• pre_dump methods are invoked before implicit field creation. Thanks makmanalp{.interpreted-text role=”user”} for reporting.
• Return correct "required" error message for Nested field.
• The only argument passed to a Schema is bounded by the fields option (183{.interpreted-text role=”issue”}). Thanks lustdante{.interpreted-text role=”user”} for the suggestion.

Changes from 2.0.0rc2:

• error_handler and accessor options are replaced with the handle_error and get_attribute methods 284{.interpreted-text role=”issue”}.
• Remove marshmallow.compat.plain_function since it is no longer used.
• Non-collection values are invalid input for List field (231{.interpreted-text role=”issue”}). Thanks density{.interpreted-text role=”user”} for reporting.
• Bug fix: Prevent infinite loop when validating a required, self-nested field. Thanks Bachmann1234{.interpreted-text role=”user”} for the fix.

2.0.0rc2 (2015-09-16)

Deprecation/Removals:

• make_object is deprecated. Use a post_load method instead (277{.interpreted-text role=”issue”}). This method will be removed in the final 2.0 release.
• Schema.accessor and Schema.error_handler decorators are deprecated. Define the accessor and error_handler class Meta options instead.

Bug fixes:

• Allow non-field names to be passed to ValidationError (273{.interpreted-text role=”issue”}). Thanks evgeny-sureev{.interpreted-text role=”user”} for the catch and patch.

Changes from 2.0.0rc1:

• The raw parameter of the pre_*, post_*, validates_schema decorators was renamed to pass_many (276{.interpreted-text role=”issue”}).
• Add pass_original parameter to post_load and post_dump (216{.interpreted-text role=”issue”}).
• Methods decorated with the pre_*, post_*, and validates_* decorators must be instance methods. Class methods and instance methods are not supported at this time.

2.0.0rc1 (2015-09-13)

Features:

• Backwards-incompatible: fields.Field._deserialize now takes attr and data as arguments (172{.interpreted-text role=”issue”}). Thanks alexmic{.interpreted-text role=”user”} and kevinastone{.interpreted-text role=”user”} for the suggestion.
• Allow a Field's attribute to be modified during deserialization (266{.interpreted-text role=”issue”}). Thanks floqqi{.interpreted-text role=”user”}.
• Allow partially-valid data to be returned for Nested fields (269{.interpreted-text role=”issue”}). Thanks jomag{.interpreted-text role=”user”} for the suggestion.
• Add Schema.on_bind_field hook which allows a Schema to modify its fields when they are bound.
• Stricter validation of string, boolean, and number fields (231{.interpreted-text role=”issue”}). Thanks touilleMan{.interpreted-text role=”user”} for the suggestion.
• Improve consistency of error messages.

Deprecation/Removals:

• Schema.validator, Schema.preprocessor, and Schema.data_handler are removed. Use validates_schema, pre_load, and post_dump instead.
• QuerySelect and QuerySelectList are deprecated (227{.interpreted-text role=”issue”}). These fields will be removed in version 2.1.
• utils.get_callable_name is removed.

Bug fixes:

• If a date format string is passed to a DateTime field, it is always used for deserialization (248{.interpreted-text role=”issue”}). Thanks bartaelterman{.interpreted-text role=”user”} and praveen-p{.interpreted-text role=”user”}.

Support:

• Documentation: Add "Using Context" section to "Extending Schemas" page (224{.interpreted-text role=”issue”}).
• Include tests and docs in release tarballs (201{.interpreted-text role=”issue”}).
• Test against Python 3.5.

2.0.0b5 (2015-08-23)

Features:

• If a field corresponds to a callable attribute, it will be called upon serialization. Thanks alexmorken{.interpreted-text role=”user”}.
• Add load_only and dump_only class Meta options. Thanks kelvinhammond{.interpreted-text role=”user”}.
• If a Nested field is required, recursively validate any required fields in the nested schema (235{.interpreted-text role=”issue”}). Thanks max-orhai{.interpreted-text role=”user”}.
• Improve error message if a list of dicts is not passed to a Nested field for which many=True. Thanks again max-orhai{.interpreted-text role=”user”}.

Bug fixes:

• [make_object]{.title-ref} is only called after all validators and postprocessors have finished (253{.interpreted-text role=”issue”}). Thanks sunsongxp{.interpreted-text role=”user”} for reporting.
• If an invalid type is passed to Schema and strict=False, store a _schema error in the errors dict rather than raise an exception (261{.interpreted-text role=”issue”}). Thanks density{.interpreted-text role=”user”} for reporting.

Other changes:

• make_object is only called when input data are completely valid (243{.interpreted-text role=”issue”}). Thanks kissgyorgy{.interpreted-text role=”user”} for reporting.
• Change default error messages for URL and Email validators so that they don't include user input (255{.interpreted-text role=”issue”}).
• Email validator permits email addresses with non-ASCII characters, as per RFC 6530 (221{.interpreted-text role=”issue”}). Thanks lextoumbourou{.interpreted-text role=”user”} for reporting and mwstobo{.interpreted-text role=”user”} for sending the patch.

2.0.0b4 (2015-07-07)

Features:

• List field respects the attribute argument of the inner field. Thanks jmcarp{.interpreted-text role=”user”}.
• The container field List field has access to its parent Schema via its parent attribute. Thanks again jmcarp{.interpreted-text role=”user”}.

Deprecation/Removals:

• Legacy validator functions have been removed (73{.interpreted-text role=”issue”}). Use the class-based validators in marshmallow.validate instead.

Bug fixes:

• fields.Nested correctly serializes nested sets (233{.interpreted-text role=”issue”}). Thanks traut{.interpreted-text role=”user”}.

Changes from 2.0.0b3:

• If load_from is used on deserialization, the value of load_from is used as the key in the errors dict (232{.interpreted-text role=”issue”}). Thanks alexmorken{.interpreted-text role=”user”}.

2.0.0b3 (2015-06-14)

Features:

• Add marshmallow.validates_schema decorator for defining schema-level validators (116{.interpreted-text role=”issue”}).
• Add marshmallow.validates decorator for defining field validators as Schema methods (116{.interpreted-text role=”issue”}). Thanks philtay{.interpreted-text role=”user”}.
• Performance improvements.
• Defining __marshallable__ on complex objects is no longer necessary.
• Add fields.Constant. Thanks kevinastone{.interpreted-text role=”user”}.

Deprecation/Removals:

• Remove skip_missing class Meta option. By default, missing inputs are excluded from serialized output (211{.interpreted-text role=”issue”}).
• Remove optional context parameter that gets passed to methods for Method fields.
• Schema.validator is deprecated. Use marshmallow.validates_schema instead.
• utils.get_func_name is removed. Use utils.get_callable_name instead.

Bug fixes:

• Fix serializing values from keyed tuple types (regression of 28{.interpreted-text role=”issue”}). Thanks makmanalp{.interpreted-text role=”user”} for reporting.

Other changes:

• Remove unnecessary call to utils.get_value for Function and Method fields (208{.interpreted-text role=”issue”}). Thanks jmcarp{.interpreted-text role=”user”}.
• Serializing a collection without passing many=True will not result in an error. Be very careful to pass the many argument when necessary.

Support:

• Documentation: Update Flask and Peewee examples. Update Quickstart.

Changes from 2.0.0b2:

• Boolean field serializes None to None, for consistency with other fields (213{.interpreted-text role=”issue”}). Thanks cmanallen{.interpreted-text role=”user”} for reporting.
• Bug fix: load_only fields do not get validated during serialization.
• Implicit passing of original, raw data to Schema validators is removed. Use @marshmallow.validates_schema(pass_original=True) instead.

2.0.0b2 (2015-05-03)

Features:

• Add useful __repr__ methods to validators (204{.interpreted-text role=”issue”}). Thanks philtay{.interpreted-text role=”user”}.
• Backwards-incompatible: By default, NaN, Infinity, and -Infinity are invalid values for fields.Decimal. Pass allow_nan=True to allow these values. Thanks philtay{.interpreted-text role=”user”}.

Changes from 2.0.0b1:

• Fix serialization of None for [Time]{.title-ref}, [TimeDelta]{.title-ref}, and [Date]{.title-ref} fields (a regression introduced in 2.0.0a1).

Includes bug fixes from 1.2.6.

2.0.0b1 (2015-04-26)

Features:

• Errored fields will not appear in (de)serialized output dictionaries (153{.interpreted-text role=”issue”}, 202{.interpreted-text role=”issue”}).
• Instantiate OPTIONS_CLASS in SchemaMeta. This makes Schema.opts available in metaclass methods. It also causes validation to occur earlier (upon Schema class declaration rather than instantiation).
• Add SchemaMeta.get_declared_fields class method to support adding additional declared fields.

Deprecation/Removals:

• Remove allow_null parameter of fields.Nested (203{.interpreted-text role=”issue”}).

Changes from 2.0.0a1:

• Fix serialization of [None]{.title-ref} for fields.Email.

2.0.0a1 (2015-04-25)

Features:

• Backwards-incompatible: When many=True, the errors dictionary returned by dump and load will be keyed on the indices of invalid items in the (de)serialized collection (75{.interpreted-text role=”issue”}). Add index_errors=False on a Schema's class Meta options to disable this behavior.
• Backwards-incompatible: By default, fields will raise a ValidationError if the input is None. The allow_none parameter can override this behavior.
• Backwards-incompatible: A Field's default parameter is only used if explicitly set and the field's value is missing in the input to [Schema.dump]{.title-ref}. If not set, the key will not be present in the serialized output for missing values . This is the behavior for all fields. fields.Str no longer defaults to '', fields.Int no longer defaults to 0, etc. (199{.interpreted-text role=”issue”}). Thanks jmcarp{.interpreted-text role=”user”} for the feedback.
• In strict mode, a ValidationError is raised. Error messages are accessed via the ValidationError's messages attribute (128{.interpreted-text role=”issue”}).
• Add allow_none parameter to fields.Field. If False (the default), validation fails when the field's value is None (76{.interpreted-text role=”issue”}, 111{.interpreted-text role=”issue”}). If allow_none is True, None is considered valid and will deserialize to None.
• Schema-level validators can store error messages for multiple fields (118{.interpreted-text role=”issue”}). Thanks ksesong{.interpreted-text role=”user”} for the suggestion.
• Add pre_load, post_load, pre_dump, and post_dump Schema method decorators for defining pre- and post- processing routines (153{.interpreted-text role=”issue”}, 179{.interpreted-text role=”issue”}). Thanks davidism{.interpreted-text role=”user”}, taion{.interpreted-text role=”user”}, and jmcarp{.interpreted-text role=”user”} for the suggestions and feedback. Thanks taion{.interpreted-text role=”user”} for the implementation.
• Error message for required validation is configurable. (78{.interpreted-text role=”issue”}). Thanks svenstaro{.interpreted-text role=”user”} for the suggestion. Thanks 0xDCA{.interpreted-text role=”user”} for the implementation.
• Add load_from parameter to fields (125{.interpreted-text role=”issue”}). Thanks hakjoon{.interpreted-text role=”user”}.
• Add load_only and dump_only parameters to fields (61{.interpreted-text role=”issue”}, 87{.interpreted-text role=”issue”}). Thanks philtay{.interpreted-text role=”user”}.
• Add [missing]{.title-ref} parameter to fields (115{.interpreted-text role=”issue”}). Thanks philtay{.interpreted-text role=”user”}.
• Schema validators can take an optional raw_data argument which contains raw input data, incl. data not specified in the schema (127{.interpreted-text role=”issue”}). Thanks ryanlowe0{.interpreted-text role=”user”}.
• Add validate.OneOf (135{.interpreted-text role=”issue”}) and validate.ContainsOnly (149{.interpreted-text role=”issue”}) validators. Thanks philtay{.interpreted-text role=”user”}.
• Error messages for validators can be interpolated with [{input}]{.title-ref} and other values (depending on the validator).
• fields.TimeDelta always serializes to an integer value in order to avoid rounding errors (105{.interpreted-text role=”issue”}). Thanks philtay{.interpreted-text role=”user”}.
• Add include class Meta option to support field names which are Python keywords (139{.interpreted-text role=”issue”}). Thanks nickretallack{.interpreted-text role=”user”} for the suggestion.
• exclude parameter is respected when used together with only parameter (165{.interpreted-text role=”issue”}). Thanks lustdante{.interpreted-text role=”user”} for the catch and patch.
• fields.List works as expected with generators and sets (185{.interpreted-text role=”issue”}). Thanks sergey-aganezov-jr{.interpreted-text role=”user”}.

Deprecation/Removals:

• MarshallingError and UnmarshallingError error are deprecated in favor of a single ValidationError (160{.interpreted-text role=”issue”}).
• context argument passed to Method fields is deprecated. Use self.context instead (184{.interpreted-text role=”issue”}).
• Remove ForcedError.
• Remove support for generator functions that yield validators (74{.interpreted-text role=”issue”}). Plain generators of validators are still supported.
• The Select/Enum field is deprecated in favor of using [validate.OneOf]{.title-ref} validator (135{.interpreted-text role=”issue”}).
• Remove legacy, pre-1.0 API (Schema.data and Schema.errors properties) (73{.interpreted-text role=”issue”}).
• Remove null value.

Other changes:

• Marshaller, Unmarshaller were moved to marshmallow.marshalling. These should be considered private API (129{.interpreted-text role=”issue”}).
• Make allow_null=True the default for Nested fields. This will make None serialize to None rather than a dictionary with empty values (132{.interpreted-text role=”issue”}). Thanks nickrellack{.interpreted-text role=”user”} for the suggestion.

1.2.6 (2015-05-03)

Bug fixes:

• Fix validation error message for fields.Decimal.
• Allow error message for fields.Boolean to be customized with the error parameter (like other fields).

1.2.5 (2015-04-25)

Bug fixes:

• Fix validation of invalid types passed to a Nested field when many=True (188{.interpreted-text role=”issue”}). Thanks juanrossi{.interpreted-text role=”user”} for reporting.

Support:

• Fix pep8 dev dependency for flake8. Thanks taion{.interpreted-text role=”user”}.

1.2.4 (2015-03-22)

Bug fixes:

• Fix behavior of as_string on fields.Integer (173{.interpreted-text role=”issue”}). Thanks taion{.interpreted-text role=”user”} for the catch and patch.

Other changes:

• Remove dead code from fields.Field. Thanks taion{.interpreted-text role=”user”}.

Support:

• Correction to _postprocess method in docs. Thanks again taion{.interpreted-text role=”user”}.

1.2.3 (2015-03-15)

Bug fixes:

• Fix inheritance of ordered class Meta option (162{.interpreted-text role=”issue”}). Thanks stephenfin{.interpreted-text role=”user”} for reporting.

1.2.2 (2015-02-23)

Bug fixes:

• Fix behavior of skip_missing and accessor options when many=True (137{.interpreted-text role=”issue”}). Thanks 3rdcycle{.interpreted-text role=”user”}.
• Fix bug that could cause an AttributeError when nesting schemas with schema-level validators (144{.interpreted-text role=”issue”}). Thanks vovanbo{.interpreted-text role=”user”} for reporting.

1.2.1 (2015-01-11)

Bug fixes:

• A Schema's error_handler--if defined--will execute if Schema.validate returns validation errors (121{.interpreted-text role=”issue”}).
• Deserializing [None]{.title-ref} returns [None]{.title-ref} rather than raising an AttributeError (123{.interpreted-text role=”issue”}). Thanks RealSalmon{.interpreted-text role=”user”} for the catch and patch.

1.2.0 (2014-12-22)

Features:

• Add QuerySelect and QuerySelectList fields (84{.interpreted-text role=”issue”}).
• Convert validators in marshmallow.validate into class-based callables to make them easier to use when declaring fields (85{.interpreted-text role=”issue”}).
• Add Decimal field which is safe to use when dealing with precise numbers (86{.interpreted-text role=”issue”}).

Thanks philtay{.interpreted-text role=”user”} for these contributions.

Bug fixes:

• Date fields correctly deserializes to a datetime.date object when python-dateutil is not installed (79{.interpreted-text role=”issue”}). Thanks malexer{.interpreted-text role=”user”} for the catch and patch.
• Fix bug that raised an AttributeError when using a class-based validator.
• Fix as_string behavior of Number fields when serializing to default value.
• Deserializing None or the empty string with either a DateTime, Date, Time or TimeDelta results in the correct unmarshalling errors (96{.interpreted-text role=”issue”}). Thanks svenstaro{.interpreted-text role=”user”} for reporting and helping with this.
• Fix error handling when deserializing invalid UUIDs (106{.interpreted-text role=”issue”}). Thanks vesauimonen{.interpreted-text role=”user”} for the catch and patch.
• Schema.loads correctly defaults to use the value of self.many rather than defaulting to False (108{.interpreted-text role=”issue”}). Thanks davidism{.interpreted-text role=”user”} for the catch and patch.
• Validators, data handlers, and preprocessors are no longer shared between schema subclasses (88{.interpreted-text role=”issue”}). Thanks amikholap{.interpreted-text role=”user”} for reporting.
• Fix error handling when passing a dict or list to a ValidationError (110{.interpreted-text role=”issue”}). Thanks ksesong{.interpreted-text role=”user”} for reporting.

Deprecation:

• The validator functions in the validate module are deprecated in favor of the class-based validators (85{.interpreted-text role=”issue”}).
• The Arbitrary, Price, and Fixed fields are deprecated in favor of the Decimal field (86{.interpreted-text role=”issue”}).

Support:

• Update docs theme.
• Update contributing docs (77{.interpreted-text role=”issue”}).
• Fix namespacing example in "Extending Schema" docs. Thanks Ch00k{.interpreted-text role=”user”}.
• Exclude virtualenv directories from syntax checking (99{.interpreted-text role=”issue”}). Thanks svenstaro{.interpreted-text role=”user”}.

1.1.0 (2014-12-02)

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{.interpreted-text role=”user”}.
• 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{.interpreted-text role=”user”} for reporting.
• If a Nested field is passed many=True, None serializes to an empty list. Thanks nickretallack{.interpreted-text role=”user”} for reporting.
• Fix behavior of many argument passed to dump and load. Thanks svenstaro{.interpreted-text role=”user”} for reporting and helping with this.
• Fix skip_missing behavior for String and List fields. Thanks malexer{.interpreted-text role=”user”} 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.

1.0.1 (2014-11-18)

Hotfix release.

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

1.0.0 (2014-11-16)

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]{.title-ref} parameter of the [Field]{.title-ref} constructor is deprecated. Raise a [ValidationError]{.title-ref} instead.
• Expanded test coverage.
• Updated docs.

1.0.0-a (2014-10-19)

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{.interpreted-text role=”user”}.
• Add Str, Bool, and Int field class aliases.

0.7.0 (2014-06-22)

• 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{.interpreted-text role=”user”} 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{.interpreted-text role=”user”}.
• More generic error message raised when required field is missing.
• validated decorator should only wrap a Field class's output method.

0.6.0 (2014-06-03)

• 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.

0.5.5 (2014-05-02)

• 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.

0.5.4 (2014-04-17)

• Add json_module class Meta option.
• Add required option to fields . Thanks DeaconDesperado{.interpreted-text role=”user”}.
• Tested on Python 3.4 and PyPy.

0.5.3 (2014-03-02)

• Fix Integer field default. It is now 0 instead of 0.0. Thanks kalasjocke{.interpreted-text role=”user”}.
• 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.

0.5.2 (2014-02-10)

• Enable custom field validation via the validate parameter.
• Add utils.from_rfc for parsing RFC datestring to Python datetime object.

0.5.1 (2014-02-02)

• Avoid unnecessary attribute access in utils.to_marshallable_type for improved performance.
• Fix RFC822 formatting for localized datetimes.

0.5.0 (2013-12-29)

• 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{.interpreted-text role=”user”}.
• 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.

0.4.1 (2013-12-01)

• 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.

0.4.0 (2013-11-24)

• Add additional [class Meta]{.title-ref} option.
• Add dateformat [class Meta]{.title-ref} 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.

0.3.1 (2013-11-16)

• 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.

0.3.0 (2013-11-14)

• 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.

0.2.1 (2013-11-12)

• Allow prefixing field names.
• Fix storing errors on Nested Serializers.
• Python 2.6 support.

0.2.0 (2013-11-11)

• 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 paramater to fields.Url that allows for relative URLs.

0.1.0 (2013-11-10)

• First release.