Primeiro, escreva toda a sua aplicação **FastAPI** normalmente:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Gerar o esquema OpenAPI { #generate-the-openapi-schema }

Em seguida, use a mesma função utilitária para gerar o esquema OpenAPI, dentro de uma função `custom_openapi()`:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Modificar o esquema OpenAPI { #modify-the-openapi-schema }

Сначала напишите приложение **FastAPI** как обычно:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Сгенерируйте схему OpenAPI { #generate-the-openapi-schema }

Затем используйте ту же вспомогательную функцию для генерации схемы OpenAPI внутри функции `custom_openapi()`:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Измените схему OpenAPI { #modify-the-openapi-schema }

from pathlib import Path

from fastapi.testclient import TestClient

from docs_src.custom_response import tutorial009_py39
from docs_src.custom_response.tutorial009_py39 import app

client = TestClient(app)


def test_get(tmp_path: Path):
    file_path: Path = tmp_path / "large-video-file.mp4"
    tutorial009_py39.some_file_path = str(file_path)
    test_content = b"Fake video bytes"
    file_path.write_bytes(test_content)

First, write all your **FastAPI** application as normally:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Generate the OpenAPI schema { #generate-the-openapi-schema }

Then, use the same utility function to generate the OpenAPI schema, inside a `custom_openapi()` function:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Modify the OpenAPI schema { #modify-the-openapi-schema }

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Generar el esquema de OpenAPI { #generate-the-openapi-schema }

Luego, usa la misma función de utilidad para generar el esquema de OpenAPI, dentro de una función `custom_openapi()`:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Modificar el esquema de OpenAPI { #modify-the-openapi-schema }

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[1,4,7:9] *}

### Das OpenAPI-Schema generieren { #generate-the-openapi-schema }

Verwenden Sie dann dieselbe Hilfsfunktion, um das OpenAPI-Schema innerhalb einer `custom_openapi()`-Funktion zu generieren:

{* ../../docs_src/extending_openapi/tutorial001_py39.py hl[2,15:21] *}

### Das OpenAPI-Schema ändern { #modify-the-openapi-schema }

import importlib

from fastapi.testclient import TestClient


def get_client() -> TestClient:
    from docs_src.conditional_openapi import tutorial001_py39

    importlib.reload(tutorial001_py39)

    client = TestClient(tutorial001_py39.app)
    return client


def test_disable_openapi(monkeypatch):
    monkeypatch.setenv("OPENAPI_URL", "")
    # Load the client after setting the env var
    client = get_client()

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[3, 6:8] *}

### Подприложение { #sub-application }

Затем создайте подприложение и его *операции пути*.

Это подприложение — обычное стандартное приложение FastAPI, но именно оно будет «смонтировано»:

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 14:16] *}

### Смонтируйте подприложение { #mount-the-sub-application }

from unittest.mock import Mock, patch

from docs_src.dependencies.tutorial007_py39 import get_db


def test_get_db():  # Just for coverage
    async def test_async_gen():
        cm = asynccontextmanager(get_db)
        async with cm() as db_session:
            return db_session

    dbsession_moock = Mock()

    with patch(
        "docs_src.dependencies.tutorial007_py39.DBSession",
        return_value=dbsession_moock,

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[3, 6:8] *}

### Sub-aplicación { #sub-application }

Luego, crea tu sub-aplicación, y sus *path operations*.

Esta sub-aplicación es solo otra aplicación estándar de FastAPI, pero es la que se "montará":

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[11, 14:16] *}

### Montar la sub-aplicación { #mount-the-sub-application }