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pythonpython-3.xfastapipydantic

Pydantic - Validation Does not Happen


I am quite new to using Pydantic.

The Issue I am facing right now is that the Model Below is not raising the Expected Exception when the value is out of range.

For example, if you pass -1 into this model it should ideally raise an HTTPException. but nothing happens

I am not sure where I might be going wrong.

Any Advice would be great.

class GetInput:
    """
    for the fields endpoint
    """

    def __init__(self,
                 rank: Optional[int] = None,
                 interval: Optional[int] = None):

        self.rank = rank
        self.interval = interval

    @validator('rank')
    def check_if_rank_in_range(cls, v):
        """
        check if input rank is within range
        """
        if not 0 < v < 1000001:

            raise HTTPException(
                status_code=400, detail="Rank Value Must be within range (0,1000000)")
        return v

    @validator('interval')
    def check_if_interval_in_range(cls, v):
        """
        check if input rank is within range
        """
        if not 0 < v < 1000001:

            raise HTTPException(
                status_code=400, detail="Interval Value Must be within range (0,1000000)")
        return v

The FastAPI Endpoint

@router.get('fields/',status_code=200)
def get_data(params: GetInput = Depends()):
    
    if params.rank:
        result = get_info_by_rank(params.rank)

    elif params.interval:

        result = get_info_by_interval(params.interval)
    
    return result

Solution

  • class GetInput(BaseModel):
    
        rank: Optional[int]=None
        interval: Optional[int]=None
        
        @validator("*")
        def check_range(cls, v):
            if v: 
                if not 0 < v < 1000001:
                    raise HTTPException(status_code=400, detail="Value Must be within range (0,1000000)")
                return v
    
    • the validator was not working due to not Inheriting the BaseModel Class
    • When the BaseModel Class would get inherited it would throw an error if either of the values is empty thus the additional if statement.