websocket: WebSocket,
    session: Union[str, None] = Cookie(default=None),
    token: Union[str, None] = Query(default=None),
):
    if session is None and token is None:
        raise WebSocketException(code=status.WS_1008_POLICY_VIOLATION)
    return session or token


@app.websocket("/items/{item_id}/ws")
async def websocket_endpoint(
    websocket: WebSocket,
    item_id: str,
    q: Union[int, None] = None,

from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/query")
def read_query(q: Union[str, None]):
    return q


@app.get("/explicit-query")
def read_explicit_query(q: Union[str, None] = Query()):
    return q


@app.post("/body-embed")
def send_body_embed(b: Union[str, None] = Body(embed=True)):
    return b


client = TestClient(app)

from pydantic import BaseModel

app = FastAPI()


class JsonApiResponse(JSONResponse):
    media_type = "application/vnd.api+json"


class Error(BaseModel):
    status: str
    title: str


class JsonApiError(BaseModel):
    errors: list[Error]


@app.get(
    "/a/{id}",
    response_class=JsonApiResponse,
    responses={422: {"description": "Error", "model": JsonApiError}},
)

from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()

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


class User(BaseModel):
    username: str


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


@app.get("/users/me")

                    buf.append(", ");
                }
                buf.append(Array.get(obj, i));
            }
            buf.append(']');
            str = buf.toString();
        } else {
            str = String.valueOf(obj);
        }
        return str;
    }

   * Converts the specified {@code String str} from this format to the specified {@code format}. A
   * "best effort" approach is taken; if {@code str} does not conform to the assumed format, then
   * the behavior of this method is undefined but we make a reasonable effort at converting anyway.
   */
  public final String to(CaseFormat format, String str) {
    checkNotNull(format);
    checkNotNull(str);

* Conversão de dados
* Validação de dados
* Documentação automatica

## Tipos especiais e validação { #special-types-and-validation }

Além dos tipos singulares normais como `str`, `int`, `float`, etc. Você também pode usar tipos singulares mais complexos que herdam de `str`.

app = FastAPI()


class Image(BaseModel):
    url: HttpUrl
    name: str


class Item(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None
    tags: set[str] = set()
    images: Union[list[Image], None] = None


class Offer(BaseModel):
    name: str
    description: Union[str, None] = None
    price: float
    items: list[Item]

     * Parses a DCERPC binding string into a DcerpcBinding object
     * @param str the binding string to parse
     * @return the parsed DcerpcBinding object
     * @throws DcerpcException if the binding string is malformed
     */
    protected static DcerpcBinding parseBinding(final String str) throws DcerpcException {
        int state, mark, si;
        final char[] arr = str.toCharArray();
        String proto = null, key = null;

     *
     * @param str
     *            the string to check
     * @return {@literal true} if the string is blank
     */
    public static boolean isBlank(final String str) {
        if (str == null || str.length() == 0) {
            return true;
        }
        for (int i = 0; i < str.length(); i++) {
            if (!Character.isWhitespace(str.charAt(i))) {
                return false;