return userCode;
        }).orElse(null);
    }

    /**
     * Extracts the user code from the user bean stored in the session.
     * This method retrieves the authenticated user information and creates an encrypted user code.
     *
     * @param request the HTTP servlet request
     * @return the user code from the user bean, or null if not found or invalid
     */

    /**
     * Creates a copy of the data suitable for retrieval from the cache. The retrieved data can be mutated after the
     * cache is queried but the state of the cache must not change so we need to make a copy.
     *
     * @param data The data to retrieve from the cache, must not be {@code null}.
     * @return The data being retrieved from the cache, never {@code null}.
     */
    T fromCache(T data);

    /**

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str, Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

# `UploadFile` class

You can define *path operation function* parameters to be of the type `UploadFile` to receive files from the request.

You can import it directly from `fastapi`:

```python
from fastapi import UploadFile
```

::: fastapi.UploadFile
    options:
        members:
            - file
            - filename
            - size
            - headers
            - content_type
            - read

from fastapi import FastAPI
from fastapi.responses import JSONResponse

app = FastAPI()


@app.get("/headers/")
def get_headers():
    content = {"message": "Hello World"}
    headers = {"X-Cat-Dog": "alone in the world", "Content-Language": "en-US"}

from fastapi import FastAPI
from pydantic import BaseModel, EmailStr

app = FastAPI()


class BaseUser(BaseModel):
    username: str
    email: EmailStr
    full_name: str | None = None


class UserIn(BaseUser):
    password: str


@app.post("/user/")
async def create_user(user: UserIn) -> BaseUser:

from base64 import b64encode

from fastapi import FastAPI, Security
from fastapi.security import HTTPBasic, HTTPBasicCredentials
from fastapi.testclient import TestClient

app = FastAPI()

security = HTTPBasic(realm="simple")


@app.get("/users/me")
def read_current_user(credentials: HTTPBasicCredentials = Security(security)):
    return {"username": credentials.username, "password": credentials.password}


client = TestClient(app)

from typing import Annotated

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    model_config = {"extra": "forbid"}

    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):

from typing import Union

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    model_config = {"extra": "forbid"}

    host: str
    save_data: bool
    if_modified_since: Union[str, None] = None
    traceparent: Union[str, None] = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: CommonHeaders = Header()):

from datetime import datetime

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Subscription(BaseModel):
    username: str
    monthly_fee: float
    start_date: datetime


@app.webhooks.post("new-subscription")
def new_subscription(body: Subscription):
    """
    When a new user subscribes to your service we'll send you a POST request with this