Using pydantic to change int to string

I am sometimes getting data that is either a string or int for 2 of my values. Im trying to figure out the best solution for handling this and I am using pydantic v2. Ive been studying the @field_validtaors(pre=True) but haven't been successful.

Here's my code:

class User(BaseModel):
    system_id: str
    db_id: str
    id: str
    record: dict
    isValid: bool

  @field_validator("id", mode='before')            <<<--------- not working
    def transform_system_id_to_str(cls, value) -> str:
        return str(value)
    
  @field_validator("system_id", mode='before')     <<<--------- not working
    def transform_system_id_to_str(cls, value: str | int) -> str:
        if isinstance(value, str):
            print('yes')
            return value
        return str(value)

You can validate more than one fields in a field_validator.

Try the following code:

class User(BaseModel):
    system_id: str
    db_id: str
    id: str
    record: dict
    isValid: bool

    @field_validator("id","system_id", mode='before')

    def transform_id_to_str(cls, value) -> str:
        return str(value)

u = User(system_id='199', db_id="1", id='99', record={}, isValid=True)
print(u)  ## system_id='199' db_id='1' id='99' record={} isValid=True

u = User(system_id=199, db_id="1", id=99, record={}, isValid=True)
print(u)  ## system_id='199' db_id='1' id='99' record={} isValid=True

Before validators run before Pydantic's internal parsing and validation (e.g. coercion of a str to an int). https://docs.pydantic.dev/latest/concepts/validators/