"msg": "value is not a valid integer",
            "type": "type_error.integer"
        }
    ]
}
```

これは、パスパラメータ `item_id` が `int` ではない値 `"foo"` だからです。

<a href="http://127.0.0.1:8000/items/4.2" class="external-link" target="_blank">http://127.0.0.1:8000/items/4.2</a> で見られるように、intのかわりに `float` が与えられた場合にも同様なエラーが表示されます。

/// check | 確認

したがって、Pythonの型宣言を使用することで、**FastAPI**はデータのバリデーションを行います。

## Проверка в действии { #try-it }

Если ваш файл называется `main.py`, то запустите приложение командой:

<div class="termy">

```console
$ fastapi dev main.py

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

Откройте браузер по адресу <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

[19511] [INFO] Application startup complete.
[19513] [INFO] Started server process [19513]
[19513] [INFO] Waiting for application startup.
[19513] [INFO] Application startup complete.
[19514] [INFO] Started server process [19514]
[19514] [INFO] Waiting for application startup.
[19514] [INFO] Application startup complete.
[19515] [INFO] Started server process [19515]
[19515] [INFO] Waiting for application startup.

# Formularios y archivos del request { #request-forms-and-files }

Puedes definir archivos y campos de formulario al mismo tiempo usando `File` y `Form`.

/// info | Información

Para recibir archivos subidos y/o form data, primero instala <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

# Formulários e Arquivos da Requisição { #request-forms-and-files }

Você pode definir arquivos e campos de formulário ao mesmo tempo usando `File` e `Form`.

/// info | Informação

Para receber arquivos carregados e/ou dados de formulário, primeiro instale <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

        ]
    }


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/": {
                "get": {
                    "responses": {
                        "200": {

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/users/me": {
                "get": {
                    "responses": {
                        "200": {

def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/items/": {
                "get": {
                    "responses": {
                        "200": {

                },
                "required": ["loc", "msg", "type"],
                "title": "ValidationError",
                "type": "object",
            },
        }
    },
    "info": {"title": "FastAPI", "version": "0.1.0"},
    "openapi": "3.1.0",
    "paths": {
        "/foo": {
            "get": {
                "operationId": "foo_handler_foo_get",
                "parameters": [

# Dados do formulário { #form-data }

Quando você precisar receber campos de formulário em vez de JSON, você pode usar `Form`.

/// info | Informação

Para usar formulários, primeiro instale <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Certifique-se de criar um [ambiente virtual](../virtual-environments.md){.internal-link target=_blank}, ativá-lo e então instalá-lo, por exemplo:

```console