from fastapi import FastAPI

app = FastAPI(swagger_ui_parameters={"syntaxHighlight": False})


@app.get("/users/{username}")
async def read_user(username: str):

def call_counter_fixture():
    return {"count": 0}


@pytest.fixture(name="app")
def app_fixture(call_counter: dict[str, int]):
    def get_db():
        call_counter["count"] += 1
        return f"db_{call_counter['count']}"

    def get_user(db: Annotated[str, Depends(get_db)]):
        return "user"

    app = FastAPI()

    @app.get("/")
    def endpoint(
        db: Annotated[str, Depends(get_db)],

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(
    strange_header: str | None = Header(default=None, convert_underscores=False),
):

            "description": "Items external docs",
            "url": "https://fastapi.tiangolo.com/",
        },
    },
]

app = FastAPI(openapi_tags=tags_metadata)


@app.get("/users/", tags=["users"])
async def get_users():
    return [{"name": "Harry"}, {"name": "Ron"}]


@app.get("/items/", tags=["items"])
async def get_items():

Und Ihre **FastAPI**-Anwendung könnte auch aus mehreren Dateien/Modulen, usw. bestehen.

### **FastAPI** Anwendungsdatei { #fastapi-app-file }

Nehmen wir an, Sie haben eine Dateistruktur wie in [Größere Anwendungen](bigger-applications.md){.internal-link target=_blank} beschrieben:

```
.
├── app
│   ├── __init__.py
│   └── main.py
```

In der Datei `main.py` haben Sie Ihre **FastAPI**-Anwendung:

from typing import Annotated

from fastapi import Cookie, FastAPI

app = FastAPI()


@app.get("/items/")
async def read_items(ads_id: Annotated[str | None, Cookie()] = None):

from fastapi import FastAPI

from .config import settings

app = FastAPI()


@app.get("/info")
async def info():
    return {
        "app_name": settings.app_name,
        "admin_email": settings.admin_email,
        "items_per_user": settings.items_per_user,

from typing import Annotated

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(user_agent: Annotated[str | None, Header()] = None):

from fastapi.testclient import TestClient

from docs_src.dependencies.tutorial010_py39 import get_db


def test_get_db():
    app = FastAPI()

    @app.get("/")
    def read_root(c: Annotated[Any, Depends(get_db)]):
        return {"c": str(c)}

    client = TestClient(app)

    dbsession_mock = Mock()

    with patch(
        "docs_src.dependencies.tutorial010_py39.DBSession",

from fastapi import FastAPI
from pydantic import BaseModel


class Item(BaseModel):
    name: str
    description: str | None = None
    price: float
    tax: float | None = None


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item):