from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[Union[str, None], Query(min_length=3)]):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

  - search.share
  - search.suggest
  - toc.follow
  icon:
    repo: fontawesome/brands/github-alt
  logo: img/icon-white.svg
  favicon: img/favicon.png
  language: en
repo_name: fastapi/fastapi
repo_url: https://github.com/fastapi/fastapi
plugins:
  social:
    cards_layout_options:
      logo: ../en/docs/img/icon-white.svg
  typeset: null
  search: null
  macros:
    include_yaml:

## Crear un `websocket` { #create-a-websocket }

En tu aplicación de **FastAPI**, crea un `websocket`:

{* ../../docs_src/websockets/tutorial001_py39.py hl[1,46:47] *}

/// note | Detalles Técnicos

También podrías usar `from starlette.websockets import WebSocket`.

from fastapi import Depends, FastAPI, Security
from fastapi.security import APIKeyQuery
from fastapi.testclient import TestClient
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")

from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security.http import HTTPAuthorizationCredentials, HTTPBase
from fastapi.testclient import TestClient

app = FastAPI()

security = HTTPBase(scheme="Other", auto_error=False)


@app.get("/users/me")
def read_current_user(
    credentials: Optional[HTTPAuthorizationCredentials] = Security(security),
):
    if credentials is None:

from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security import OAuth2AuthorizationCodeBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2AuthorizationCodeBearer(
    authorizationUrl="authorize", tokenUrl="token", auto_error=True
)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    return {"token": token}

from typing import Annotated, Union

from fastapi import Cookie, FastAPI
from pydantic import BaseModel

app = FastAPI()


class Cookies(BaseModel):
    session_id: str
    fatebook_tracker: Union[str, None] = None
    googall_tracker: Union[str, None] = None


@app.get("/items/")
async def read_items(cookies: Annotated[Cookies, Cookie()]):

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    description: str


items = [
    {"name": "Foo", "description": "There comes my hero"},
    {"name": "Red", "description": "It's my aeroplane"},
]


@app.get("/items/", response_model=list[Item])
async def read_items():

from enum import Enum

from fastapi import FastAPI

app = FastAPI()


class Tags(Enum):
    items = "items"
    users = "users"


@app.get("/items/", tags=[Tags.items])
async def get_items():
    return ["Portal gun", "Plumbus"]


@app.get("/users/", tags=[Tags.users])
async def read_users():

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Annotated[
        str | None, Query(min_length=3, max_length=50, regex="^fixedquery$")
    ] = None,
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})