import static com.google.common.base.Preconditions.checkNotNull;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Random;

/** Returns a random portion of the requested bytes on each call. */
class RandomAmountInputStream extends FilterInputStream {
  private final Random random;

  public RandomAmountInputStream(InputStream in, Random random) {
    super(checkNotNull(in));

///

```Python hl_lines="7-12  16"
{!> ../../docs_src/header_param_models/tutorial001_py310.py!}
```

////

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">

        });
        try (InputStream inputStream = form.protwordsFile.getInputStream()) {
            file.update(inputStream);
        } catch (final IOException e) {
            logger.warn("Failed to process a request.", e);
            throwValidationErrorApi(messages -> messages.addErrorsFailedToUploadProtwordsFile(GLOBAL));
        }
        return asJson(new ApiResult.ApiResponse().status(ApiResult.Status.OK).result());
    }

`CORSMiddleware` отвечает на два типа HTTP-запросов...

### CORS-запросы с предварительной проверкой

Это любые `OPTIONS` запросы с заголовками `Origin` и `Access-Control-Request-Method`.

В этом случае middleware перехватит входящий запрос и отправит соответствующие CORS-заголовки в ответе, а также ответ `200` или `400` в информационных целях.

### Простые запросы

# Header-Parameter

So wie `Query`-, `Path`-, und `Cookie`-Parameter können Sie auch <abbr title='Header – Kopfzeilen, Header, Header-Felder: Schlüssel-Wert-Metadaten, die vom Client beim Request, und vom Server bei der Response gesendet werden'>Header</abbr>-Parameter definieren.

## `Header` importieren

Importieren Sie zuerst `Header`:

//// tab | Python 3.10+

```Python hl_lines="3"
{!> ../../docs_src/header_params/tutorial001_an_py310.py!}
```

        this.managedVersionMap = managedVersionMap;

        return this;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder()
                .append("REQUEST: ")
                .append("\n")
                .append("artifact: ")
                .append(mad)
                .append("\n")
                .append(artifactDependencies)
                .append("\n")

  @Throws(IOException::class)
  override fun writeTo(sink: BufferedSink) {
    writeOrCountBytes(sink, false)
  }

  /**
   * Either writes this request to [sink] or measures its content length. We have one method
   * do double-duty to make sure the counting and content are consistent, particularly when it comes

        if (cause instanceof LoginUnauthorizedException) {
            return asJson(createFailureBean(Status.UNAUTHORIZED, "Unauthorized request.")).httpStatus(HTTP_UNAUTHORIZED);
        }
        return asJson(createFailureBean(Status.BAD_REQUEST, createMessage(resource, cause))).httpStatus(HTTP_BAD_REQUEST);
    }

        final StringBuilder buf = new StringBuilder();
        clientFactory.addClient("test:.*", new CrawlerClient() {
            @Override
            public ResponseData execute(final RequestData request) {
                return null;
            }

            @Override
            public void setInitParameterMap(final Map<String, Object> params) {
                buf.append("value=").append(params.get("hoge"));

    /** Sets the socket policy and returns this. */
    fun socketPolicy(socketPolicy: SocketPolicy) =
      apply {
        this.socketPolicy = socketPolicy
      }

    /**
     * Throttles the request reader and response writer to sleep for the given period after each
     * series of [bytesPerPeriod] bytes are transferred. Use this to simulate network behavior.
     */
    fun throttleBody(
      bytesPerPeriod: Long,