Signal

Danio support signal during instance's life cycle, all sql operation interact with model instance (receive or return instance as param) will call those signal method:

• after_read - called after the instance has been read from database

  async def after_read(self) -> None

• before_create - called before the instance has been created to database

• after_create - called after the instance has been created to database
• before_update
• after_update
• before_delete
• after_delete

Special signal:

• after_init - called after the instance has been init (call by __post_init__ actually)

  def after_init(self) -> None

eg:

count = 0
@dataclasses.dataclass
class Pet(danio.Model):
    name: str = danio.field(danio.CharField)
    age: int = danio.field(danio.IntField)
    code: str = ""

    def after_init(self):
        super().after_init()
        self.code = f"{self.name}_{self.age}"

    async def after_create(self):
        await super().after_create()
        count += 1

    async def after_delete(self):
        await super().after_delete()
        count -= 1