Object

Let's go back to the user model and try to validate json

{
  "id": 1,
  "username": "some",
  "email": "other"
}

Let's describe our model

from models_manager import Model, Field


class User(Model):
    id = Field(default=1, json='id', category=int)
    username = Field(default='some', json='username', category=str)
    email = Field(default='other', json='email', category=str)

We described the model where we indicated the categories for each field

Note

You can read more about categories and other field arguments here

Now let's generate a schema that will describe how the json of our model should look like.

from models_manager import Model, Field


class User(Model):
    id = Field(default=1, json='id', category=int)
    username = Field(default='some', json='username', category=str)
    email = Field(default='other', json='email', category=str)


User.manager.to_schema

{
    'type': 'object',
    'properties': {
        'id': {'type': 'number'},
        'username': {'type': 'string'},
        'email': {'type': 'string'}
    },
    'required': ['id', 'username', 'email']
}

From here we see that:

id - number
username - string
email - string

Max length

Let's add more specifics for some fields

from models_manager import Model, Field


class User(Model):
    id = Field(default=1, json='id', category=int)
    username = Field(default='some', json='username', category=str, max_length=100)
    email = Field(default='other', json='email', category=str, max_length=70)


User.manager.to_schema

{
    'type': 'object',
    'properties': {
        'id': {'type': 'number'},
        'username': {
            'type': 'string',
            'minLength': 0,
            'maxLength': 100
        },
        'email': {
            'type': 'string',
            'minLength': 0,
            'maxLength': 70
        }
    },
    'required': ['id', 'username', 'email']
}

Now we can see that the username is in a certain length range from 0 to 100, just like the email field

Required

Now let's see how we can validate optional fields in an object. Imagine now that the user object has an optional token field, which may or may not be

{
  "id": 1,
  "username": "some",
  "email": "other"
}

Also valid

{
  "id": 1,
  "username": "some",
  "email": "other",
  "token": "some-token"
}

Let's add a new token field to our user model

from models_manager import Model, Field


class User(Model):
    id = Field(default=1, json='id', category=int)
    username = Field(default='some', json='username', category=str)
    email = Field(default='other', json='email', category=str)
    token = Field(default='some-token', json='token', is_related=True)


{
    'type': 'object',
    'properties': {
        'id': {'type': 'number'},
        'username': {'type': 'string'},
        'email': {'type': 'string'},
        'token': {'type': ['string', 'null']}
    },
    'required': ['id', 'username', 'email']
}

Note

Notice that we have added the is_related argument to the token field. You can read more about field arguments here