def get_user_items(
        user_me: Annotated[dict, Depends(get_user_me)],
    ):
        call_counts["get_user_items"] += 1
        return {
            "user_items": f"user_items_{call_counts['get_user_items']}",
            "user_me": user_me,
        }

    app = FastAPI()

    @app.get("/")
    def path_operation(
        user_me: Annotated[dict, Depends(get_user_me)],

from fastapi import Depends, FastAPI
from fastapi.requests import HTTPConnection
from fastapi.testclient import TestClient
from starlette.websockets import WebSocket

app = FastAPI()
app.state.value = 42


async def extract_value_from_http_connection(conn: HTTPConnection):
    return conn.app.state.value


@app.get("/http")
async def get_value_by_http(value: int = Depends(extract_value_from_http_connection)):
    return value

from fastapi import Depends, FastAPI

app = FastAPI()


async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: dict = Depends(common_parameters)):
    return commons


@app.get("/users/")
async def read_users(commons: dict = Depends(common_parameters)):

from fastapi import Depends, FastAPI

app = FastAPI()


async def common_parameters(q: str | None = None, skip: int = 0, limit: int = 100):
    return {"q": q, "skip": skip, "limit": limit}


@app.get("/items/")
async def read_items(commons: Annotated[dict, Depends(common_parameters)]):
    return commons


@app.get("/users/")
async def read_users(commons: Annotated[dict, Depends(common_parameters)]):

/// info | Technical Details

`Security` is actually a subclass of `Depends`, and it has just one extra parameter that we'll see later.

But by using `Security` instead of `Depends`, **FastAPI** will know that it can declare security scopes, use them internally, and document the API with OpenAPI.

But when you import `Query`, `Path`, `Depends`, `Security` and others from `fastapi`, those are actually functions that return special classes.

from fastapi import Depends, FastAPI, Security
from fastapi.security import SecurityScopes
from fastapi.testclient import TestClient

app = FastAPI()


def get_user(required_scopes: SecurityScopes):
    return "john", required_scopes.scopes


def get_user_override(required_scopes: SecurityScopes):
    return "alice", required_scopes.scopes


def get_data():
    return [1, 2, 3]


def get_data_override():

# Ref: https://github.com/fastapi/fastapi/issues/14271
from fastapi import Depends, FastAPI
from fastapi.security import HTTPBearer
from fastapi.testclient import TestClient
from inline_snapshot import snapshot

app = FastAPI()

bearer_scheme = HTTPBearer()


@app.get("/", dependencies=[Depends(bearer_scheme)])
async def get_root():
    return {"message": "Hello, World!"}

from fastapi import Depends, FastAPI, Header, HTTPException


async def verify_token(x_token: str = Header()):
    if x_token != "fake-super-secret-token":
        raise HTTPException(status_code=400, detail="X-Token header invalid")


async def verify_key(x_key: str = Header()):
    if x_key != "fake-super-secret-key":
        raise HTTPException(status_code=400, detail="X-Key header invalid")
    return x_key

import secrets

from fastapi import Depends, FastAPI, HTTPException, status
from fastapi.security import HTTPBasic, HTTPBasicCredentials

app = FastAPI()

security = HTTPBasic()


def get_current_username(credentials: HTTPBasicCredentials = Depends(security)):
    current_username_bytes = credentials.username.encode("utf8")
    correct_username_bytes = b"stanleyjobson"
    is_correct_username = secrets.compare_digest(

  <description>
    An empty artifact that Guava depends on to signal that it is providing
    ListenableFuture -- but is also available in a second "version" that
    contains com.google.common.util.concurrent.ListenableFuture class, without
    any other Guava classes. The idea is:

    - If users want only ListenableFuture, they depend on listenablefuture-1.0.

    - If users want all of Guava, they depend on guava, which, as of Guava
    27.0, depends on