System.out.println("Vary: " + response.headers("Vary"));
        }
      }
    ```

### Posting a String ([.kt][PostStringKotlin], [.java][PostStringJava])

Use an HTTP POST to send a request body to a service. This example posts a markdown document to a web service that renders markdown as HTML. Because the entire request body is in memory simultaneously, avoid posting large (greater than 1 MiB) documents using this API.

    @callback_router.post(
        "/post-callback",
        response_model=List[Item],
        responses={404: {"model": List[Message]}},
        generate_unique_id_function=custom_generate_unique_id3,
    )
    def post_callback(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    @app.post(
        "/",
        response_model=List[Item],

class Coordinate(BaseModel):
    x: float
    y: float


@app.post("/model-with-tuple/")
def post_model_with_tuple(item_group: ItemGroup):
    return item_group


@app.post("/tuple-of-models/")
def post_tuple_of_models(square: Tuple[Coordinate, Coordinate]):
    return square


@app.post("/tuple-form/")
def hello(values: Tuple[int, int] = Form()):
    return values

        monkeypatch.delattr("multipart.multipart.parse_options_header", raising=False)
    with pytest.raises(RuntimeError, match=multipart_incorrect_install_error):
        app = FastAPI()

        @app.post("/")
        async def root(username: str = Form()):
            return username  # pragma: nocover


def test_incorrect_multipart_installed_file_upload(monkeypatch):

@needs_pydanticv2
def test_post_body_form(client: TestClient):
    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


@needs_pydanticv2
def test_post_body_extra_form(client: TestClient):
    response = client.post(
        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )

@needs_pydanticv1
def test_post_body_form(client: TestClient):
    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


@needs_pydanticv1
def test_post_body_extra_form(client: TestClient):
    response = client.post(
        "/login/", data={"username": "Foo", "password": "secret", "extra": "extra"}
    )

def test_post_body_form(client: TestClient):
    response = client.post("/login/", data={"username": "Foo", "password": "secret"})
    assert response.status_code == 200
    assert response.json() == {"username": "Foo", "password": "secret"}


# TODO: remove when deprecating Pydantic v1
@needs_pydanticv1
@needs_py39
def test_post_body_extra_form(client: TestClient):
    response = client.post(

        {
            "loc": ["body", "file"],
            "msg": "field required",
            "type": "value_error.missing",
        }
    ]
}


def test_post_form_no_body():
    response = client.post("/files/")
    assert response.status_code == 422, response.text
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "missing",

from dirty_equals import IsDict
from fastapi.testclient import TestClient

from docs_src.request_files.tutorial001_an import app

client = TestClient(app)


def test_post_form_no_body():
    response = client.post("/files/")
    assert response.status_code == 422, response.text
    assert response.json() == IsDict(
        {
            "detail": [
                {
                    "type": "missing",

    response = client.post(f"/?z={value}")
    assert response.status_code == code, response.text


@pytest.mark.parametrize(
    "value,code",
    [
        ("-1", 200),
        ("inf", 422),
        ("-inf", 422),
        ("nan", 422),
        ("0", 200),
        ("342", 200),
    ],
)
def test_allow_inf_nan_body(value: str, code: int):
    response = client.post("/", json=value)