# Advanced Middleware { #advanced-middleware }

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md) to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md).

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares { #adding-asgi-middlewares }

    return if (address is InetSocketAddress) address.hostName else address.toString()
  }

  companion object {
    val logger: Logger = Logger.getLogger(Http2Server::class.java.name)

    @JvmStatic
    fun main(args: Array<String>) {
      if (args.size != 1 || args[0].startsWith("-")) {
        println("Usage: Http2Server <base directory>")
        return
      }
      val server =
        Http2Server(

Gardez à l'esprit que les dataclasses ne peuvent pas tout ce que peuvent faire les modèles Pydantic.

Vous pourriez donc avoir encore besoin d'utiliser des modèles Pydantic.

Mais si vous avez déjà un ensemble de dataclasses sous la main, c'est une astuce pratique pour les utiliser afin d'alimenter une API Web avec FastAPI. 🤓

///

## Utiliser des dataclasses dans `response_model` { #dataclasses-in-response-model }

**FastAPI** provides the same `starlette.responses` as `fastapi.responses` just as a convenience for you, the developer. But most of the available responses come directly from Starlette.

///

### `Response` { #response }

The main `Response` class, all the other responses inherit from it.

You can return it directly.

It accepts the following parameters:

* `content` - A `str` or `bytes`.
* `status_code` - An `int` HTTP status code.

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Помилка імпорту sirius, його не встановлено 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

* [`Parameter Object` (в спецификации)](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#parameter-object), которое использовалось в FastAPI:
    * `Path()`
    * `Query()`
    * `Header()`
    * `Cookie()`
* [`Request Body Object`, в поле `content`, в `Media Type Object` (в спецификации)](https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#media-type-object), которое использовалось в FastAPI:
    * `Body()`

// license that can be found in the LICENSE file.

// This program can be used as go_ios_$GOARCH_exec by the Go tool. It executes
// binaries on the iOS Simulator using the XCode toolchain.
package main

import (
	"fmt"
	"go/build"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"syscall"
)

const debug = false

var tmpdir string

var (
	devID    string

    else:
      line_str += ('Couldn\'t parse the bazel command, '
                   'check inside the build log instead')
    line_str += f'\n{url}\n'
    print(line_str)
    i += 1


def main():
  args = parse_args()
  verbose = args.verbose
  build_log_path = os.path.expandvars(args.build_log)
  links = parse_log(build_log_path, verbose=verbose)

  if args.xml_out_path:

      if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

      System.out.println(response.body().string());
    }
  }

  public static void main(String... args) throws Exception {
    new Progress().run();
  }

  private static class ProgressResponseBody extends ResponseBody {

    private final ResponseBody responseBody;

import okhttp3.survey.types.Client
import okhttp3.survey.types.SuiteId
import okio.FileSystem
import okio.Path.Companion.toPath
import org.conscrypt.Conscrypt

@Suppress("ktlint:standard:property-naming")
suspend fun main() {
  val includeConscrypt = false

  val client =
    OkHttpClient
      .Builder()
      .cache(Cache(FileSystem.SYSTEM, "build/okhttp_cache".toPath(), 100_000_000))
      .build()