```

////

### Check the password

At this point we have the user data from our database, but we haven't checked the password.

Let's put that data in the Pydantic `UserInDB` model first.

You should never save plaintext passwords, so, we'll use the (fake) password hashing system.

If the passwords don't match, we return the same error.

#### Password hashing

            server = server.clone();

            String password = server.getPassword();
            if (securityDispatcher.isAnyEncryptedString(password)) {
                try {
                    if (securityDispatcher.isLegacyEncryptedString(password)) {
                        problems.add(new DefaultSettingsProblem(
                                "Legacy/insecurely encrypted password detected for server " + server.getId(),

#### Passwort-Hashing

„Hashing“ bedeutet: Konvertieren eines Inhalts (in diesem Fall eines Passworts) in eine Folge von Bytes (ein schlichter String), die wie Kauderwelsch aussieht.

Immer wenn Sie genau den gleichen Inhalt (genau das gleiche Passwort) übergeben, erhalten Sie genau den gleichen Kauderwelsch.

Sie können jedoch nicht vom Kauderwelsch zurück zum Passwort konvertieren.

##### Warum Passwort-Hashing verwenden?

    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


@needs_pydanticv2
def test_post_body_extra_form(client: TestClient):
    response = client.post(
        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )
    assert response.status_code == 422

class OAuth2PasswordRequestForm:
    """
    This is a dependency class to collect the `username` and `password` as form data
    for an OAuth2 password flow.

    The OAuth2 specification dictates that for a password flow the data should be
    collected using form data (instead of JSON) and that it should have the specific
    fields `username` and `password`.

    All the initialization parameters are extracted from the request.

    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


@needs_pydanticv1
def test_post_body_extra_form(client: TestClient):
    response = client.post(
        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )
    assert response.status_code == 422

///

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

But you cannot convert from the gibberish back to the password.

### Why use password hashing

    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


# TODO: remove when deprecating Pydantic v1
@needs_pydanticv1
@needs_py39
def test_post_body_extra_form(client: TestClient):
    response = client.post(
        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )

def test_login_incorrect_username():
    response = client.post("/token", data={"username": "foo", "password": "secret"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "Incorrect username or password"}


def test_no_token():
    response = client.get("/users/me")
    assert response.status_code == 401, response.text

    assert response.json() == {"detail": "Incorrect username or password"}


@needs_py39
def test_login_incorrect_username(client: TestClient):
    response = client.post("/token", data={"username": "foo", "password": "secret"})
    assert response.status_code == 400, response.text
    assert response.json() == {"detail": "Incorrect username or password"}


@needs_py39
def test_no_token(client: TestClient):