Enforces that all incoming requests have a correctly set `Host` header, in order to guard against HTTP Host Header attacks.

```Python hl_lines="2  6-8"
{!../../../docs_src/advanced_middleware/tutorial002.py!}
```

The following arguments are supported:

But when checking benchmarks and comparisons you should keep the following in mind.

## Benchmarks and speed

When you check the benchmarks, it is common to see several tools of different types compared as equivalent.

## Available versions

You can see the available versions (e.g. to check what is the current latest) in the [Release Notes](../release-notes.md){.internal-link target=_blank}.

## About versions

Following the Semantic Versioning conventions, any version below `1.0.0` could potentially add breaking changes.

FastAPI also follows the convention that any "PATCH" version change is for bug fixes and non-breaking changes.

!!! tip

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# Metadata and Docs URLs

You can customize several metadata configurations in your **FastAPI** application.

## Metadata for API

You can set the following fields that are used in the OpenAPI specification and the automatic API docs UIs:

| Parameter | Type | Description |
|------------|------|-------------|
| `title` | `str` | The title of the API. |

    "ignore::trio.TrioDeprecationWarning",
    # TODO remove pytest-cov
    'ignore::pytest.PytestDeprecationWarning:pytest_cov',
    # TODO: remove after upgrading SQLAlchemy to a version that includes the following changes
    # https://github.com/sqlalchemy/sqlalchemy/commit/59521abcc0676e936b31a523bd968fc157fef0c2

And you can use and implement secure, standard protocols, like OAuth2 in a relatively simple way.

        That's a lot of work they are doing, but if more FastAPI users came to help others like them just a little bit more, it would be much less effort for them (and you and me 😅).

        By asking questions in a structured way (following this) it will be much easier to help you.

        And there's a high chance that you will find the solution along the way and you won't even have to submit it and wait for an answer. 😎

## Motivation

Let's start with a simple example:

```Python
{!../../../docs_src/python_types/tutorial001.py!}
```

Calling this program outputs:

```
John Doe
```

The function does the following:

* Takes a `first_name` and `last_name`.
* Converts the first letter of each one to upper case with `title()`.

### `UploadFile`

`UploadFile` has the following attributes:

* `filename`: A `str` with the original file name that was uploaded (e.g. `myimage.jpg`).
* `content_type`: A `str` with the content type (MIME type / media type) (e.g. `image/jpeg`).