أجسام الطلب والتحقق بـPydantic

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel, ConfigDict, Field
class Item(BaseModel):
    model_config = ConfigDict(extra="forbid")
    name: str
    quantity: int = Field(gt=0)
app = FastAPI()
@app.post("/items")
def create(item: Item): return item.model_dump()
with TestClient(app) as client:
    print(client.post("/items", json={"name": "pen", "quantity": "2"}).json())
    print(client.post("/items", json={"name": "pen", "quantity": 2, "admin": True}).status_code)

{'name': 'pen', 'quantity': 2}
422

ينتج التحويل العدد 2 ويرفض admin المجهول 422 قبل عبور الحد.

from pydantic import BaseModel, ConfigDict, ValidationError, model_validator
class Window(BaseModel):
    model_config = ConfigDict(strict=True)
    start: int
    end: int
    @model_validator(mode="after")
    def ordered(self):
        if self.end <= self.start:
            raise ValueError("end must exceed start")
        return self
print(Window(start=1, end=3).model_dump())
try:
    Window(start=3, end=1)
except ValidationError as error:
    print(error.errors()[0]["type"])
try:
    Window(start="1", end=3)
except ValidationError as error:
    print(error.errors()[0]["type"])

{'start': 1, 'end': 3}
value_error
int_type

ينجح الترتيب ويعطي عكسه value_error والنص الصارم int_type دون أثر خارجي.