Validation

flarchitect ships with a suite of field validators that hook directly into Marshmallow. Validators can be attached to a model column via the SQLAlchemy info mapping or inferred automatically from column names and formats.

For a runnable example demonstrating email and URL validation see the validators demo.

Basic usage

class Author(db.Model):
    email = db.Column(
        db.String,
        info={"validate": "email"},
    )
    website = db.Column(
        db.String,
        info={"format": "uri"},  # auto adds URL validation
    )

When invalid data is sent to the API a 400 response is returned:

{
  "errors": {"email": ["Email address is not valid."]},
  "status_code": 400,
  "value": null
}

Field validation

flarchitect inspects the info mapping and the optional format attribute on SQLAlchemy columns to determine which validators to apply. When API_AUTO_VALIDATE is enabled, common formats such as email or date are added automatically based on column names. Any validator supported by validate_by_type can also be assigned manually:

class Payment(db.Model):
    account = db.Column(db.String, info={"validate": "iban"})
    cron = db.Column(db.String, info={"format": "cron"})

This associates the iban and cron validators with the account and cron columns respectively. Invalid values cause Marshmallow to raise a ValidationError and the API will respond with 400.

Multiple validators can be applied to a single column by providing a list:

class Contact(db.Model):
    identifier = db.Column(
        db.String,
        info={"validate": ["email", "slug"]},
    )

Submitting invalid data returns messages for each failed validator:

{
  "errors": {"identifier": ["Email address is not valid.", "Value must be a valid slug."]},
  "status_code": 400,
  "value": null
}

Custom error messages can also be supplied via a mapping:

class Employee(db.Model):
    email = db.Column(
        db.String,
        info={"validate": {"email": "Invalid email"}},
    )

Invalid values return the custom message:

{
  "errors": {"email": ["Invalid email"]},
  "status_code": 400,
  "value": null
}

Available validators

validate_by_type supports the following names:

• email

• url

• ipv4

• ipv6

• mac

• slug

• uuid

• card

• country_code

• domain

• md5

• sha1

• sha224

• sha256

• sha384

• sha512

• hostname

• iban

• cron

• base64

• currency

• phone

• postal_code

• date

• datetime

• time

• boolean

• decimal