import time
from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException
from fastapi.responses import StreamingResponse
from sqlmodel import Field, Session, SQLModel, create_engine

engine = create_engine("postgresql+psycopg://postgres:postgres@localhost/db")


class User(SQLModel, table=True):
    id: int | None = Field(default=None, primary_key=True)
    name: str


app = FastAPI()


def get_session():

`Depends`を渡すだけで、**FastAPI** が残りの処理をしてくれます。

///

## `Annotated` 依存関係の共有 { #share-annotated-dependencies }

上の例では、ほんの少し **コードの重複** があることがわかります。

`common_parameters()` 依存関係を使う必要があるときは、型アノテーションと `Depends()` を含むパラメータ全体を書く必要があります:

```Python
commons: Annotated[dict, Depends(common_parameters)]
```

しかし、`Annotated` を使用しているので、その `Annotated` 値を変数に格納して複数箇所で使えます:

from typing import Annotated

from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel, WithJsonSchema

app = FastAPI()


class Item(BaseModel):
    name: str

    description: Annotated[str | None, WithJsonSchema({"type": ["string", "null"]})] = (
        None
    )

    model_config = {
        "json_schema_extra": {
            "x-something-internal": {"level": 4},
        }

from typing import Annotated

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


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


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            openapi_examples={

from typing import Annotated

from fastapi import Body, FastAPI
from pydantic import BaseModel

app = FastAPI()


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


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Annotated[
        Item,
        Body(
            examples=[
                {

from collections.abc import Callable
from typing import Annotated

from fastapi import Body, FastAPI, HTTPException, Request, Response
from fastapi.exceptions import RequestValidationError
from fastapi.routing import APIRoute


class ValidationErrorLoggingRoute(APIRoute):
    def get_route_handler(self) -> Callable:
        original_route_handler = super().get_route_handler()

        async def custom_route_handler(request: Request) -> Response:

from typing import Annotated

from fastapi import Depends, FastAPI, HTTPException

app = FastAPI()


class InternalError(Exception):
    pass


def get_username():
    try:
        yield "Rick"
    except InternalError:
        print("We don't swallow the internal error here, we raise again 😎")
        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):

from collections.abc import AsyncIterable
from typing import Annotated

from fastapi import FastAPI, Header
from fastapi.sse import EventSourceResponse, ServerSentEvent
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float


items = [
    Item(name="Plumbus", price=32.99),
    Item(name="Portal Gun", price=999.99),
    Item(name="Meeseeks Box", price=49.99),
]

"""
Regression test: preserve order when using list[bytes] + File()
See https://github.com/fastapi/fastapi/discussions/14811
Fixed in PR: https://github.com/fastapi/fastapi/pull/14884
"""

from typing import Annotated

import anyio
import pytest
from fastapi import FastAPI, File
from fastapi.testclient import TestClient
from starlette.datastructures import UploadFile as StarletteUploadFile


def test_list_bytes_file_preserves_order(

from typing import Annotated

from fastapi import FastAPI, File, UploadFile
from fastapi.responses import HTMLResponse

app = FastAPI()


@app.post("/files/")
async def create_files(files: Annotated[list[bytes], File()]):
    return {"file_sizes": [len(file) for file in files]}


@app.post("/uploadfiles/")
async def create_upload_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}