redis-om-python/docs/validation.md

Validation

Redis OM uses Pydantic behind the scenes to validate data at runtime, based on the model's type annotations.

Basic Type Validation

Validation works for basic type annotations like str. Thus, given the following model:

class Customer(HashModel):
    first_name: str
    last_name: str
    email: EmailStr
    join_date: datetime.date
    age: int
    bio: Optional[str]

... Redis OM will ensure that first_name is always a string.

But every Redis OM model is also a Pydantic model, so you can use existing Pydantic validators like EmailStr, Pattern, and many more for complex validation!

Complex Validation

Let's see what happens if we try to create a Customer object with an invalid email address.

# We'll get a validation error if we try to use an invalid email address!
Customer(
    first_name="Andrew",
    last_name="Brookins",
    email="Not an email address!",
    join_date=datetime.date.today(),
    age=38,
    bio="Python developer, works at Redis, Inc."
)

This code generates the following error:

 Traceback:
 pydantic.error_wrappers.ValidationError: 1 validation error for Customer
 email
   value is not a valid email address (type=value_error.email)

We'll also get a validation error if we change a field on a model instance to an invalid value and then try to save it:

andrew = Customer(
    first_name="Andrew",
    last_name="Brookins",
    email="andrew.brookins@example.com",
    join_date=datetime.date.today(),
    age=38,
    bio="Python developer, works at Redis, Inc."
)

andrew.email = "Not valid"
andrew.save()

Once again, we get the valiation error:

 Traceback:
 pydantic.error_wrappers.ValidationError: 1 validation error for Customer
 email
   value is not a valid email address (type=value_error.email)