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Project description

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


  • 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',

CreateUser = Schema(

payload = CreateUser.load({'username': ''})
assert payload.username == ''
assert payload.password is None
assert payload.date_of_birth is None



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

CreateUser = Schema(
    Field('username', required=True),
    Field('password', required=True),
user = CreateUser.from_request()

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