kanagata 0.0

restricted dict

Providing extracted dict (subclass of collections.UserDict).

how to use

(todo: description)

models.py

from kanagata import RestrictionBuilder

# group: name, users
# user: name, age, Option[skills], Option[school]
# skill: name
with RestrictionBuilder() as b:
    with b.define_dict("Group") as group:
        group.add_member("name", required=True)
        group.add_list("users", "User", required=True)

    with b.define_dict("User") as user:
        user.add_member("name", required=True)
        user.add_member("age", required=True)
        user.add_dict("school", "School", required=False)
        user.add_list("skills", "Skill", required=False)

    with b.define_dict("Skill") as skill:
        skill.add_member("name", required=True)

    with b.define_dict("School") as school:
        school.add_member("name")
        school.add_list("groups", "Group", required=True)

from models import User

# user can have only name, age, skills. (skills is optional)

user = User(name="foo", age=20, skills=[])
print(user)  # {'name': 'foo', 'age': 20, 'skills': []}

try:
    user2 = User(name="bar")
    # ValueError: User: required fields {'age'} are not found
except ValueError:
    pass

try:
    user["xxx"] = "bar"
    # ValueError: User: unsupported field 'xxx', field members=['name', 'age', 'school', 'skills']
except ValueError:
    pass

# user.skills can have only name.

user["skills"].append({"name": "math"})
print(user)  # {'skills': [{'name': 'math'}], 'age': 20, 'name': 'foo'}

try:
    user["skills"].append({})
    # ValueError: Skill: required fields {'name'} are not found
except ValueError:
    pass