## Zusätzliche Response mit `model`

Sie können Ihren *Pfadoperation-Dekoratoren* einen Parameter `responses` übergeben.

Der nimmt ein `dict` entgegen, die Schlüssel sind Statuscodes für jede Response, wie etwa `200`, und die Werte sind andere `dict`s mit den Informationen für jede Response.

E.g.:

* To pass a *path* or *query* parameter, add it to the URL itself.
* To pass a JSON body, pass a Python object (e.g. a `dict`) to the parameter `json`.
* If you need to send *Form Data* instead of JSON, use the `data` parameter instead.
* To pass *headers*, use a `dict` in the `headers` parameter.
* For *cookies*, a `dict` in the `cookies` parameter.

# Response Headers

## Use a `Response` parameter

You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies).

And then you can set headers in that *temporal* response object.

```Python hl_lines="1  7-8"
{!../../docs_src/response_headers/tutorial002.py!}
```

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

            digest.sign( dst, headerStart, length, this, response );
        }

        return length;
    }

    /*
     * We overload this because we want readAndXWireFormat to
     * read the parameter words and bytes. This is so when
     * commands are batched together we can recursivly call
     * readAndXWireFormat without reading the non-existent header.
     */

    int decode( byte[] buffer, int bufferIndex ) {

## Using `BackgroundTasks`

First, import `BackgroundTasks` and define a parameter in your *path operation function* with a type declaration of `BackgroundTasks`:

{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}

**FastAPI** will create the object of type `BackgroundTasks` for you and pass it as that parameter.

## Create a task function

Create a function to be run as the background task.

        Object proxy, Method method, @Nullable Object[] args) {
      Invokable<?, ?> invokable = interfaceType.method(method);
      ImmutableList<Parameter> params = invokable.getParameters();
      for (int i = 0; i < args.length; i++) {
        Parameter param = params.get(i);
        if (!isNullable(param)) {
          checkNotNull(args[i]);
        }
      }

Als Teil der Erstellung des Anwendungsobjekts wird eine *Pfadoperation* für `/openapi.json` (oder welcher Wert für den Parameter `openapi_url` gesetzt wurde) registriert.

Diese gibt lediglich eine JSON-Response zurück, mit dem Ergebnis der Methode `.openapi()` der Anwendung.

  }

  /**
   * Returns all declared parameters of this {@code Invokable}. Note that if this is a constructor
   * of a non-static inner class, unlike {@link Constructor#getParameterTypes}, the hidden {@code
   * this} parameter of the enclosing class is excluded from the returned parameters.
   */
  @IgnoreJRERequirement
  public final ImmutableList<Parameter> getParameters() {

 */

package com.google.common.collect.testing.google;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import com.google.common.annotations.GwtCompatible;
import java.lang.annotation.Retention;

 */

package com.google.common.collect.testing.testers;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import com.google.common.annotations.GwtCompatible;
import java.lang.annotation.Retention;