Source: Pydantic-validation-custom

← Rendered

markdown source:

---
description: Кастомная валидация типов в pydantic
title: Pydantic-validation-custom
tags: pydantic python
---
Кастомная валиддация для python в [[pydantic]] делается с помощью специального декоратора

```python
from pydantic import BaseModel, ValidationError, validator


class UserModel(BaseModel):
    name: str
    username: str
    password1: str
    password2: str

    @validator('name')
    def name_must_contain_space(cls, v):
        if ' ' not in v:
            raise ValueError('must contain a space')
        return v.title()

    @validator('password2')
    def passwords_match(cls, v, values, **kwargs):
        if 'password1' in values and v != values['password1']:
            raise ValueError('passwords do not match')
        return v

    @validator('username')
    def username_alphanumeric(cls, v):
        assert v.isalnum(), 'must be alphanumeric'
        return v


user = UserModel(
    name='samuel colvin',
    username='scolvin',
    password1='zxcvbn',
    password2='zxcvbn',
)
print(user)
#> name='Samuel Colvin' username='scolvin' password1='zxcvbn' password2='zxcvbn'

try:
    UserModel(
        name='samuel',
        username='scolvin',
        password1='zxcvbn',
        password2='zxcvbn2',
    )
except ValidationError as e:
    print(e)
    """
    2 validation errors for UserModel
    name
      must contain a space (type=value_error)
    password2
      passwords do not match (type=value_error)
    """
```

[Другие аспекты валидации в примерах](https://pydantic-docs.helpmanual.io/usage/validators/)

[Смотри так-же python email validator](https://github.com/JoshData/python-email-validator)

[[pydantic]]




[pydantic]: pydantic "Pydantic"