```JSON hl_lines="4-16"
{
    "components": {
        "schemas": {
            "Message": {
                "title": "Message",
                "required": [
                    "message"
                ],
                "type": "object",
                "properties": {
                    "message": {
                        "title": "Message",
                        "type": "string"
                    }
                }

### Checking the current `root_path`

You can get the current `root_path` used by your application for each request, it is part of the `scope` dictionary (that's part of the ASGI spec).

Here we are including it in the message just for demonstration purposes.

```Python hl_lines="8"
{!../../../docs_src/behind_a_proxy/tutorial001.py!}
```

Then, if you start Uvicorn with:

<div class="termy">

```console

```txt
Hello, World from Flask!
```

并且如果您访问 <a href="http://localhost:8000/v2" class="external-link" target="_blank">http://localhost:8000/v2</a>，您将会看到由 FastAPI 返回的响应：

```JSON
{
    "message": "Hello World"
}

            else:
                return None
        return HTTPAuthorizationCredentials(scheme=scheme, credentials=credentials)


class HTTPBasic(HTTPBase):
    """
    HTTP Basic authentication.

    ## Usage

    Create an instance object and use that object as the dependency in `Depends()`.

    The dependency result will be an `HTTPBasicCredentials` object containing the
    `username` and the `password`.

                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},
                        "type": {"title": "Error Type", "type": "string"},
                    },
                },
            }
        },

            ]
        }
    )


def test_root_token_jessica(client: TestClient):
    response = client.get("/?token=jessica")
    assert response.status_code == 200
    assert response.json() == {"message": "Hello Bigger Applications!"}


def test_root_with_no_token(client: TestClient):
    response = client.get("/")
    assert response.status_code == 422
    assert response.json() == IsDict(
        {

        }
    )


@needs_py39
def test_root_token_jessica(client: TestClient):
    response = client.get("/?token=jessica")
    assert response.status_code == 200
    assert response.json() == {"message": "Hello Bigger Applications!"}


@needs_py39
def test_root_with_no_token(client: TestClient):
    response = client.get("/")
    assert response.status_code == 422
    assert response.json() == IsDict(

                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},
                        "type": {"title": "Error Type", "type": "string"},
                    },
                },
                "HTTPValidationError": {

                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},
                        "type": {"title": "Error Type", "type": "string"},
                    },
                },
                "HTTPValidationError": {

                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},
                        "type": {"title": "Error Type", "type": "string"},
                    },
                },
                "HTTPValidationError": {