Sie können diese Exceptionhandler mit Ihren eigenen überschreiben.

### Überschreiben von Request-Validierungs-Exceptions { #override-request-validation-exceptions }

Wenn ein Request ungültige Daten enthält, löst **FastAPI** intern einen `RequestValidationError` aus.

Und es enthält auch einen Default-Exceptionhandler für diesen.

                return option.get();
            }

            // Apply default behavior: if no specific options are provided, use default
            if (options.all().isEmpty()
                    && options.infer().isEmpty()
                    && options.model().isEmpty()
                    && options.plugins().isEmpty()
                    && options.modelVersion().isEmpty()) {
                return defaultValue;
            }

Но в нашем случае одно и то же приложение **FastAPI** будет работать и с API, и с аутентификацией.

Итак, рассмотрим это с упрощенной точки зрения:

* Пользователь вводит на фронтенде `username` и `password` и нажимает `Enter`.
* Фронтенд (работающий в браузере пользователя) отправляет эти `username` и `password` на конкретный URL в нашем API (объявленный с `tokenUrl="token"`).

        }
    }

    @Override
    public String toString() {
        return "StopwordsFile [path=" + path + ", stopwordsItemList=" + stopwordsItemList + ", id=" + id + "]";
    }

    /**
     * An inner class for updating the stopwords file.
     * This class handles the process of writing changes to a temporary file
     * and then replacing the original file upon successful commit.
     */

        assertNull(result);
    }

    // Test convertBooleanQuery with nested BooleanQuery
    @Test
    public void test_convertBooleanQuery_withNestedBooleanQuery() {
        // Create inner BooleanQuery
        BooleanQuery.Builder innerBoolQueryBuilder = new BooleanQuery.Builder();
        TermQuery innerTermQuery = new TermQuery(new Term("innerField", "innerValue"));

O = MyOrg
OU = MyOU
CN = MyServerName

[v3_req]
subjectAltName = @alt_names

[alt_names]
IP.1 = 127.0.0.1
DNS.1 = localhost
```

Run `openssl` by specifying the configuration file and enter a passphrase if prompted:

```sh
openssl req -new -x509 -nodes -days 730 -keyout private.key -out public.crt -config openssl.conf
```

### 3.3 Use GnuTLS (for Windows) to Generate a Certificate

        generator.setCommandTimeout(-1L);
        generator.setCommandTimeout(Long.MAX_VALUE);

        assertTrue("Timeout edge cases should be handled", true);
    }

    // Test ProcessDestroyer inner class
    @Test
    public void test_processDestroyer_creation() throws Exception {
        // We can't directly test ProcessDestroyer without creating actual processes,

    }

    @Test
    @DisplayName("reauthenticate propagates transport failures")
    void testReauthenticatePropagates() throws Exception {
        SmbSessionImpl session = newSession();
        // Cause the inner reauthenticate to fail at first transport call
        when(transport.getNegotiateResponse()).thenThrow(new SmbException("fail"));
        assertThrows(CIFSException.class, session::reauthenticate);
    }

<img src="/img/tutorial/path-params/image02.png">

Und viele weitere kompatible Tools. Inklusive Codegenerierung für viele Sprachen.

## Pydantic { #pydantic }

But in this case, the same **FastAPI** application will handle the API and the authentication.

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).