app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={
        200: {
            "content": {"image/png": {}},
            "description": "Return the JSON item or an image.",
        }
    },
)
async def read_item(item_id: str, img: Union[bool, None] = None):
    if img:

        "paths": {
            "/items/{item_id}": {
                "put": {
                    "parameters": [
                        {
                            "in": "path",
                            "name": "item_id",
                            "required": True,
                            "schema": {
                                "title": "Item Id",
                                "type": "integer",

                        "summary": "Read Item Name",
                        "operationId": "read_item_name_items__item_id__name_get",
                        "parameters": [
                            {
                                "required": True,
                                "schema": {"title": "Item Id", "type": "string"},
                                "name": "item_id",
                                "in": "path",

                        "summary": "Read Item Name",
                        "operationId": "read_item_name_items__item_id__name_get",
                        "parameters": [
                            {
                                "required": True,
                                "schema": {"title": "Item Id", "type": "string"},
                                "name": "item_id",
                                "in": "path",

    )
    return TestClient(mod.app)


@pytest.mark.parametrize(
    "path,expected_response",
    [
        ("/items/42", {"item_id": 42}),
        ("/items/123?item-query=somequery", {"item_id": 123, "q": "somequery"}),
    ],
)
def test_read_items(client: TestClient, path, expected_response):
    response = client.get(path)

from pydantic import BaseModel


class Item(BaseModel):
    id: str
    value: str


responses = {
    404: {"description": "Item not found"},
    302: {"description": "The item was moved"},
    403: {"description": "Not enough privileges"},
}


app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={**responses, 200: {"content": {"image/png": {}}}},

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):

        "paths": {
            "/items/{item_id}": {
                "put": {
                    "parameters": [
                        {
                            "in": "path",
                            "name": "item_id",
                            "required": True,
                            "schema": {
                                "title": "Item Id",
                                "type": "integer",

{* ../../docs_src/path_params/tutorial001.py hl[6:7] *}

La valeur du paramètre `item_id` sera transmise à la fonction dans l'argument `item_id`.

Donc, si vous exécutez cet exemple et allez sur <a href="http://127.0.0.1:8000/items/foo" class="external-link" target="_blank">http://127.0.0.1:8000/items/foo</a>,
vous verrez comme réponse :

```JSON
{"item_id":"foo"}
```

## Paramètres de chemin typés