What's the canonical way to add a custom method to a model class? #653
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Example Code# model.py (simplified)
class PersonBase(SQLModel):
first_name: str
last_name: str
name_suffix: Optional[str] = None
nickname: Optional[str] = None
def full_name(self) -> str:
full_name = f"{self.first_name} {self.last_name}"
if self.name_suffix:
if self.name_suffix in ["II", "III", "IV"]:
full_name = f"{full_name} {self.name_suffix}"
else:
full_name = f"{full_name}, {self.name_suffix}"
return full_name
class Person(PersonBase, table=True):
id: Optional[int] = Field(default=None, primary_key=True)
class PersonCreate(PersonBase):
pass
class PersonRead(PersonBase):
id: int
full_name: str
class PersonUpdate(SQLModel):
first_name: Optional[str] = None
last_name: Optional[str] = None
name_suffix: Optional[str] = None
nickname: Optional[str] = None
# Person routers
router = APIRouter(
prefix="/persons",
tags=["persons"],
responses={404: {"description": "Not found"}},
)
@router.post("/", response_model=PersonRead)
def create_person(*, session: Session = Depends(get_session), person: Person):
person = Person.from_orm(person)
session.add(person)
session.commit()
session.refresh(person)
return person
@router.get("/", response_model=List[PersonRead])
def read_persons(
*,
session: Session = Depends(get_session),
offset: int = 0,
limit: int = Query(default=100, lte=100)
):
persons = session.exec(select(Person).offset(offset).limit(limit)).all()
return persons
# TODO: Get endpoint to return a value for the full_name method
@router.get("/{person_id}", response_model=PersonRead)
def read_person(*, session: Session = Depends(get_session), person_id: int):
person = session.get(Person, person_id)
if not person:
raise HTTPException(status_code=404, detail="Person not found")
full_name = person.full_name()
person_dict = person.__dict__
person_dict["full_name"] = full_name
return PersonRead(**person_dict)
@router.delete("/{person_id}")
def delete_person(*, session: Session = Depends(get_session), person_id: int):
person = session.get(Person, person_id)
if not person:
raise HTTPException(status_code=404, detail="Person not found")
session.delete(person)
session.commit()
return {"ok": True}DescriptionIn addition to the fields defined in my For example, a request for With the code above, I get the following Traceback: Operating SystemOther Operating System DetailsRunning in a Docker container on macOS. SQLModel Version0.0.8 Python Version3.12.0 Additional ContextNo response |
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Replies: 3 comments 2 replies
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It's actually a property, so you should use a And the error is because you have shadowed the |
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Thanks so much, @wojciech-mazur-mlg. So I guess the bigger question is whether this is a good practice? It seems like this would be a convenient place to build out a few convenience methods that would be annoying for someone to do on the client side. Is there a different approach that would be a better long-term practice? |
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It is a good practice to use properties. It allows to deliver values based on other fields to expose convenient class interface and reuse code. If you want to include those properties in your models you should add also |
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Thanks for that information. I couldn't do a In any case, my |
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It seems that I have this working now. The URL |
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It's actually a property, so you should use a
@propertydecorator onfull_namemethod.And the error is because you have shadowed the
full_nameattribute. You can removefull_namefromPersonReadclass.