```Python hl_lines="10"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="10"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="11"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an.py!}
    ```

    ```Python hl_lines="10"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="10"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an_py39.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="11"
    {!> ../../../docs_src/query_params_str_validations/tutorial003_an.py!}
    ```

# 查询参数和字符串校验

**FastAPI** 允许你为参数声明额外的信息和校验。

让我们以下面的应用程序为例：

=== "Python 3.10+"

    ```Python hl_lines="7"
    {!> ../../../docs_src/query_params_str_validations/tutorial001_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/query_params_str_validations/tutorial001.py!}
    ```

查询参数 `q` 的类型为 `str`，默认值为 `None`，因此它是可选的。

## 额外的校验

## Détails techniques

Les versions modernes de Python supportent le **code asynchrone** grâce aux **"coroutines"** avec les syntaxes **`async` et `await`**.

Analysons les différentes parties de cette phrase dans les sections suivantes :

* **Code asynchrone**
* **`async` et `await`**
* **Coroutines**

## Code asynchrone

            {"in": "main-depends", "params": {"q": None, "skip": 5, "limit": 10}},
        ),
        (
            "/main-depends/?q=foo",
            200,
            {"in": "main-depends", "params": {"q": "foo", "skip": 5, "limit": 10}},
        ),
        (
            "/main-depends/?q=foo&skip=100&limit=200",
            200,
            {"in": "main-depends", "params": {"q": "foo", "skip": 5, "limit": 10}},

::: fastapi.WebSocket
    options:
        members:
            - scope
            - app
            - url
            - base_url
            - headers
            - query_params
            - path_params
            - cookies
            - client
            - state
            - url_for
            - client_state
            - application_state
            - receive
            - send

"docs_src/dependencies/tutorial008_an.py" = ["F821"]
"docs_src/dependencies/tutorial008_an_py39.py" = ["F821"]
"docs_src/query_params_str_validations/tutorial012_an.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial012_an_py39.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial013_an.py" = ["B006"]
"docs_src/query_params_str_validations/tutorial013_an_py39.py" = ["B006"]
"docs_src/security/tutorial004.py" = ["B904"]

* ✏ Fix typo in `docs/en/docs/tutorial/query-params-str-validations.md`. PR [#9272](https://github.com/tiangolo/fastapi/pull/9272) by [@nicornk](https://github.com/nicornk).
* ✏ Fix typo/bug in inline code example in `docs/en/docs/tutorial/query-params-str-validations.md`. PR [#9273](https://github.com/tiangolo/fastapi/pull/9273) by [@tim-habitat](https://github.com/tim-habitat).

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.query_params.tutorial005 import app

client = TestClient(app)


def test_foo_needy_very():
    response = client.get("/items/foo?needy=very")
    assert response.status_code == 200
    assert response.json() == {"item_id": "foo", "needy": "very"}


def test_foo_no_needy():
    response = client.get("/items/foo")

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.body_multiple_params.tutorial001_an import app

    client = TestClient(app)
    return client


def test_post_body_q_bar_content(client: TestClient):
    response = client.put("/items/5?q=bar", json={"name": "Foo", "price": 50.5})
    assert response.status_code == 200