## Agregar más validaciones { #add-more-validations }

También puedes agregar un parámetro `min_length`:

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## Agregar expresiones regulares { #add-regular-expressions }

由于 `Annotated` 可以包含多个元数据标注，你甚至可以用同一个函数与其他工具配合，例如 [Typer](https://typer.tiangolo.com/)。🚀

## 添加更多校验 { #add-more-validations }

你还可以添加 `min_length` 参数：

{* ../../docs_src/query_params_str_validations/tutorial003_an_py310.py hl[10] *}

## 添加正则表达式 { #add-regular-expressions }

                "type": "string_too_short",
                "loc": ["path", "item_id"],
                "msg": "String should have at least 3 characters",
                "input": "fo",
                "ctx": {"min_length": 3},
            }
        ]
    }


def test_path_param_maxlength_foo():
    response = client.get("/path/param-maxlength/foo")
    assert response.status_code == 200

@app.post("/items/")
async def create_items(items: Annotated[list[int], Field(min_length=1), Body()]):
    return items
```

instead of:

```python
# DO NOT DO THIS
from typing import Annotated

from fastapi import FastAPI
from pydantic import Field, RootModel

app = FastAPI()


class ItemList(RootModel[Annotated[list[int], Field(min_length=1)]]):
    pass


@app.post("/items/")

        }

        buffer.append(' ').append(message);

        // CHECKSTYLE_OFF: LineLength
        problems.add(new ModelProblemCollectorRequest(severity, version)
                .setMessage(buffer.toString())
                .setLocation(getLocation(fieldName, tracker)));
        // CHECKSTYLE_ON: LineLength
    }

    private static InputLocation getLocation(String fieldName, InputLocationTracker tracker) {

    termsOfService: str | None = None
    contact: Contact | None = None
    license: License | None = None
    version: str


class ServerVariable(BaseModelWithConfig):
    enum: Annotated[list[str] | None, Field(min_length=1)] = None
    default: str
    description: str | None = None


class Server(BaseModelWithConfig):
    url: AnyUrl | str
    description: str | None = None
    variables: dict[str, ServerVariable] | None = None

app = FastAPI()


@app.get("/items/{item_id}")
def main(
    item_id: int = Path(default=..., gt=0),
    query: str = Query(default=..., max_length=10),
    session: str = Cookie(default=..., min_length=3),
    x_trace: str = Header(default=..., title="Tracing header"),
):
    return {"message": "Hello World"}
```

...all these parameters are required because the default value is `...` (Ellipsis).