wr-schemas

A schema describes:

1. a data structure

2. a mapping of one data structure into another

A schema consists of a list of fields.

A field doesn’t have a type – it is a type itself, in a way. Instead of a type, a field has a bi-directional mapping. Given two different data structures x and y, a mapping describes how to calculate x.f from y.f and how to calculate y.f from x.f.

Fields support following attributes:

• name

• mapping

• default

• source_name (source_names)

• min_len, max_len, auto_trim

• min, max

• choices

• regex

• required, forbidden

• nullable

Also:

• Nested fields are supported.

• Fields are easy to clone for reuse.

• Fields and schemas are easy to reverse.

• Schemas are easy to chain.

from wr_schemas import Field, Schema, Mappings


class Fields:
    user_id = Field('id', mapping=int, min=1)
    user_username = Field('username', min_len=5, max_len=100, regex=r'^[a-zA-Z0-9_\-\.@]+$')
    user_password = Field('password', min_len=10, max_len=100, regex=r'^[a-zA-Z0-9]+$')
    user_dob = Field('date_of_birth', mapping=Mappings.date())


CreateUser = Schema(
    Fields.user_username.clone(required=True),
    Fields.user_password.clone(default=None),
    Fields.user_dob.clone(default=None),
)

payload = CreateUser.load({'username': 'marcus.aurelius@rome.gov'})
assert payload.username == 'marcus.aurelius@rome.gov'
assert payload.password is None
assert payload.date_of_birth is None

print(CreateUser.dump(payload))

Flask:

from wr_schemas import Field, Schema, Mappings
from wr_schemas.flask_request import FlaskRequestSchemaMixin

CreateUser = Schema(
    Field('username', required=True),
    Field('password', required=True),
    mixins=[FlaskRequestSchemaMixin],
)
user = CreateUser.from_request()