## Conditional OpenAPI from settings and env vars

You can easily use the same Pydantic settings to configure your generated OpenAPI and the docs UIs.

For example:

```Python hl_lines="6  11"
{!../../../docs_src/conditional_openapi/tutorial001.py!}
```

Here we declare the setting `openapi_url` with the same default of `"/openapi.json"`.

And then we use it when creating the `FastAPI` app.

By default, what the method `.openapi()` does is check the property `.openapi_schema` to see if it has contents and return them.

If it doesn't, it generates them using the utility function at `fastapi.openapi.utils.get_openapi`.

And that function `get_openapi()` receives as parameters:

* `title`: The OpenAPI title, shown in the docs.

## 設定と環境変数による条件付き OpenAPI

生成するOpenAPIとドキュメントUIの構成は、共通のPydanticの設定を使用して簡単に切り替えられます。

例えば、

```Python hl_lines="6  11"
{!../../../docs_src/conditional_openapi/tutorial001.py!}
```

ここでは `openapi_url` の設定を、デフォルトの `"/openapi.json"` のまま宣言しています。

そして、これを `FastAPI` appを作る際に使います。

それから、以下のように `OPENAPI_URL` という環境変数を空文字列に設定することによってOpenAPI (UIドキュメントを含む) を無効化することができます。

<div class="termy">

## Bedingte OpenAPI aus Einstellungen und Umgebungsvariablen

Sie können problemlos dieselben Pydantic-Einstellungen verwenden, um Ihre generierte OpenAPI und die Dokumentationsoberflächen zu konfigurieren.

Zum Beispiel:

```Python hl_lines="6  11"
{!../../../docs_src/conditional_openapi/tutorial001.py!}
```

Hier deklarieren wir die Einstellung `openapi_url` mit dem gleichen Defaultwert `"/openapi.json"`.

openapi: 3.0.3
info:
  title: Fess - User API
  description: |-
    This is a Fess Server based on the OpenAPI 3.0 specification.  
  license:
    name: Apache 2.0
    url: http://www.apache.org/licenses/LICENSE-2.0.html
  version: 14.8.0
externalDocs:
  description: API Documentation
  url: https://fess.codelibs.org/14.8/api/
servers:
  - url: http://localhost:8080/api/v1
tags:
  - name: search
    description: Search operations

# Separate OpenAPI-Schemas für Eingabe und Ausgabe oder nicht

Bei Verwendung von **Pydantic v2** ist die generierte OpenAPI etwas genauer und **korrekter** als zuvor. 😎

Tatsächlich gibt es in einigen Fällen sogar **zwei JSON-Schemas** in OpenAPI für dasselbe Pydantic-Modell für Eingabe und Ausgabe, je nachdem, ob sie **Defaultwerte** haben.

Sehen wir uns an, wie das funktioniert und wie Sie es bei Bedarf ändern können.

## Pydantic-Modelle für Eingabe und Ausgabe

# Separate OpenAPI Schemas for Input and Output or Not

When using **Pydantic v2**, the generated OpenAPI is a bit more exact and **correct** than before. 😎

In fact, in some cases, it will even have **two JSON Schemas** in OpenAPI for the same Pydantic model, for input and output, depending on if they have **default values**.

Let's see how that works and how to change it if you need to do that.

## Pydantic Models for Input and Output

    response = client.get("/cookie_examples/")
    assert response.status_code == 200, response.text


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": {
            "/examples/": {

def test_app():
    response = client.get("/foo")
    assert response.status_code == 200, response.text


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"},
        "servers": [

    assert response.status_code == 200, response.text
    assert response.json() == {"c": {}, "d": {"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": {
            "/": {
                "get": {