!!! info
    Ein „Pfad“ wird häufig auch als „Endpunkt“ oder „Route“ bezeichnet.

Bei der Erstellung einer API ist der „Pfad“ die wichtigste Möglichkeit zur Trennung von „Anliegen“ und „Ressourcen“.

#### Operation

„Operation“ bezieht sich hier auf eine der HTTP-„Methoden“.

Eine von diesen:

* `POST`
* `GET`
* `PUT`
* `DELETE`

... und die etwas Exotischeren:

* `OPTIONS`
* `HEAD`
* `PATCH`

Для некоторых типов приложений может потребоваться добавить зависимости ко всему приложению.

Подобно тому, как вы можете [добавлять зависимости через параметр `dependencies` в *декораторах операций пути*](dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, вы можете добавлять зависимости сразу ко всему `FastAPI` приложению.

В этом случае они будут применяться ко всем *операциям пути* в приложении:

=== "Python 3.9+"

from docs_src.additional_responses.tutorial001 import app

client = TestClient(app)


def test_path_operation():
    response = client.get("/items/foo")
    assert response.status_code == 200, response.text
    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_not_found():
    response = client.get("/items/bar")
    assert response.status_code == 404, response.text

from docs_src.additional_responses.tutorial002 import app

client = TestClient(app)


def test_path_operation():
    response = client.get("/items/foo")
    assert response.status_code == 200, response.text
    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_img():
    shutil.copy("./docs/en/docs/img/favicon.png", "./image.png")
    response = client.get("/items/foo?img=1")

from docs_src.additional_responses.tutorial003 import app

client = TestClient(app)


def test_path_operation():
    response = client.get("/items/foo")
    assert response.status_code == 200, response.text
    assert response.json() == {"id": "foo", "value": "there goes my hero"}


def test_path_operation_not_found():
    response = client.get("/items/bar")
    assert response.status_code == 404, response.text

# Background Tasks - `BackgroundTasks`

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

# Body - Fields

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field`

First, you have to import it:

=== "Python 3.10+"

    ```Python hl_lines="4"
    {!> ../../../docs_src/body_fields/tutorial001_an_py310.py!}
    ```

=== "Python 3.9+"

8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

# `Request` class

You can declare a parameter in a *path operation function* or dependency to be of type `Request` and then you can access the raw request object directly, without any validation, etc.

You can import it directly from `fastapi`:

```python
from fastapi import Request
```

!!! tip

from fastapi.testclient import TestClient

from docs_src.response_change_status_code.tutorial001 import app

client = TestClient(app)


def test_path_operation():
    response = client.put("/get-or-create-task/foo")
    print(response.content)
    assert response.status_code == 200, response.text
    assert response.json() == "Listen to the Bar Fighters"
    response = client.put("/get-or-create-task/bar")