* @param form the form containing the request header data
     * @param username the username of the user performing the operation
     * @param currentTime the current timestamp
     * @return optional entity containing the request header data, or empty if creation fails
     */
    public static OptionalEntity<RequestHeader> getEntity(final CreateForm form, final String username, final long currentTime) {
        switch (form.crudMode) {

     *
     * @param form the create form
     * @param username the current username
     * @param currentTime the current time
     * @return optional file authentication entity
     */
    public static OptionalEntity<FileAuthentication> getEntity(final CreateForm form, final String username, final long currentTime) {
        switch (form.crudMode) {
        case CrudMode.CREATE:

@app.get("/items/")
async def read_items():
    return [{"item": "Portal Gun"}, {"item": "Plumbus"}]


@app.get("/users/")
async def read_users():

	currTime := UTCNow()

	var (
		username = cred.AccessKey
		claims   = cred.Claims
		groups   = cred.Groups
	)

	if cred.IsTemp() || cred.IsServiceAccount() {
		// For derived credentials, check the parent user's permissions.
		username = cred.ParentUser
	}

	principalType := "Anonymous"
	if username != "" {
		principalType = "User"
		if len(claims) > 0 {

from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyQuery(name="key", description="API Key Query")


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str = Security(api_key)):
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User = Depends(get_current_user)):
    return current_user

from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyQuery(name="key", auto_error=False)


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str | None = Security(api_key)):
    if oauth_header is None:
        return None
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User | None = Depends(get_current_user)):

# パスワードとBearerによるシンプルなOAuth2 { #simple-oauth2-with-password-and-bearer }

前章から発展させて、完全なセキュリティフローに必要な不足部分を追加していきます。

## `username` と `password` を取得する { #get-the-username-and-password }

`username` と `password` を取得するために **FastAPI** のセキュリティユーティリティを使います。

OAuth2 では、「password flow」（ここで使用するフロー）を使う場合、クライアント/ユーザーはフォームデータとして `username` と `password` フィールドを送信する必要があります。

しかも、フィールド名はこの通りでなければなりません。つまり、`user-name` や `email` では動作しません。

     * @param username The username for which to change the password.
     * @param password The new password.
     * @return True if the password was successfully changed in all chains, false otherwise.
     */
    public boolean changePassword(final String username, final String password) {
        return chains().get(stream -> stream.allMatch(c -> c.changePassword(username, password)));
    }

    /**

        except (ValueError, UnicodeDecodeError, binascii.Error) as e:
            raise self.make_not_authenticated_error() from e
        username, separator, password = data.partition(":")
        if not separator:
            raise self.make_not_authenticated_error()
        return HTTPBasicCredentials(username=username, password=password)


class HTTPBearer(HTTPBase):
    """
    HTTP Bearer token authentication.

    ## Usage

from pydantic import BaseModel

app = FastAPI()

api_key = APIKeyCookie(name="key", auto_error=False)


class User(BaseModel):
    username: str


def get_current_user(oauth_header: str | None = Security(api_key)):
    if oauth_header is None:
        return None
    user = User(username=oauth_header)
    return user


@app.get("/users/me")
def read_current_user(current_user: User = Depends(get_current_user)):