from collections.abc import AsyncIterable

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

app = FastAPI()


class Prompt(BaseModel):
    text: str


@app.post("/chat/stream", response_class=EventSourceResponse)
async def stream_chat(prompt: Prompt) -> AsyncIterable[ServerSentEvent]:
    words = prompt.text.split()
    for word in words:

from fastapi import FastAPI, Path

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(q: str, item_id: int = Path(title="The ID of the item to get")):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (o `str | None = None` en Python 3.10) tiene un valor por defecto de `None`.
* `tax: float = 10.5` tiene un valor por defecto de `10.5`.
* `tags: List[str] = []` tiene un valor por defecto de una list vacía: `[]`.

pero podrías querer omitirlos del resultado si no fueron en realidad almacenados.

*パスパラメータ*を受け取る *path operation* をもち、有効な*パスパラメータ*の値を事前に定義したい場合は、標準のPython <abbr title="Enumeration - 列挙型">`Enum`</abbr> を利用できます。

### `Enum` クラスの作成 { #create-an-enum-class }

`Enum` をインポートし、 `str` と `Enum` を継承したサブクラスを作成します。

`str` を継承することで、APIドキュメントは値が `string` 型でなければいけないことを知り、正確にレンダリングできるようになります。

そして、固定値のクラス属性を作ります。すると、その値が使用可能な値となります:

{* ../../docs_src/path_params/tutorial005_py310.py hl[1,6:9] *}

/// tip | 豆知識

from fastapi import FastAPI, Query

app = FastAPI()


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

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: str,
    size: Annotated[float, Query(gt=0, lt=10.5)],
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

/// tip

This is probably not as important or necessary if you use `Annotated`.

///

Let's say that you want to declare the query parameter `q` as a required `str`.

And you don't need to declare anything else for that parameter, so you don't really need to use `Query`.

But you still need to use `Path` for the `item_id` path parameter. And you don't want to use `Annotated` for some reason.

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


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

   *
   * {@snippet :
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()

### `UploadFile` { #uploadfile }

`UploadFile` a les attributs suivants :

- `filename` : une `str` contenant le nom de fichier original téléversé (par ex. `myimage.jpg`).
- `content_type` : une `str` avec le type de contenu (type MIME / type média) (par ex. `image/jpeg`).