# Background Tasks { #background-tasks }

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

	} unicode_string;

	/* 
	 * typedef struct _SID_IDENTIFIER_AUTHORITY {
	 *     UCHAR Value[6];
	 * } SID_IDENTIFIER_AUTHORITY, *PSID_IDENTIFIER_AUTHORITY;
	 * 
	 * #define SECURITY_NT_AUTHORITY           {0,0,0,0,0,5}
	 * 
	 * typedef struct _SID {
	 *    UCHAR Revision;
	 *    UCHAR SubAuthorityCount;
	 *    SID_IDENTIFIER_AUTHORITY IdentifierAuthority;

	} unicode_string;

	/* 
	 * typedef struct _SID_IDENTIFIER_AUTHORITY {
	 *     UCHAR Value[6];
	 * } SID_IDENTIFIER_AUTHORITY, *PSID_IDENTIFIER_AUTHORITY;
	 * 
	 * #define SECURITY_NT_AUTHORITY           {0,0,0,0,0,5}
	 * 
	 * typedef struct _SID {
	 *    UCHAR Revision;
	 *    UCHAR SubAuthorityCount;
	 *    SID_IDENTIFIER_AUTHORITY IdentifierAuthority;

    /** @deprecated use lifecycles instead */
    @Deprecated
    private Map<String, LifecyclePhase> phases;

    /**
     * Default ctor for plexus compatibility: lifecycles are most commonly defined in Plexus XML, that does field
     * injection. Still, for Plexus to be able to instantiate this class, default ctor is needed.
     *
     * @deprecated Should not be used in Java code.
     */
    @Deprecated

public class CollectionSerializationEqualTester<E> extends AbstractCollectionTester<E> {
  @CollectionFeature.Require(SERIALIZABLE)
  /*
   * As the class docs say, this test only makes sense for collections that define equals().
   * Accordingly, our testing framework adds it only when testing an implementation of List, Set, or
   * Multiset.
   */
  @SuppressWarnings("UndefinedEquals")
  public void testReserialize() {

{* ../../docs_src/query_param_models/tutorial001_an_py310.py hl[9:13,17] *}

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

## Check the Docs { #check-the-docs }

You can see the query parameters in the docs UI at `/docs`:

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

```console
$ pip install python-multipart
```

///

## Import `Form` { #import-form }

Import `Form` from `fastapi`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[3] *}

## Define `Form` parameters { #define-form-parameters }

Create form parameters the same way you would for `Body` or `Query`:

{* ../../docs_src/request_forms/tutorial001_an_py39.py hl[9] *}

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <!-- Shared parent. Doesn't define a lot of things about Apache like general mailing lists, but does
       define the settings common to all projects at Apache -->
  <groupId>org.apache</groupId>
  <artifactId>apache</artifactId>
  <version>1</version>
  <packaging>pom</packaging>

## Eine Anwendung mit Callbacks { #an-app-with-callbacks }

Sehen wir uns das alles anhand eines Beispiels an.

Stellen Sie sich vor, Sie entwickeln eine Anwendung, mit der Sie Rechnungen erstellen können.

Diese Rechnungen haben eine `id`, einen optionalen `title`, einen `customer` (Kunde) und ein `total` (Gesamtsumme).

# Parâmetros de Cookie { #cookie-parameters }

Você pode definir parâmetros de Cookie da mesma maneira que define parâmetros com `Query` e `Path`.

## Importe `Cookie` { #import-cookie }

Primeiro importe `Cookie`:

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[3] *}

## Declare parâmetros de `Cookie` { #declare-cookie-parameters }

Então declare os parâmetros de cookie usando a mesma estrutura que em `Path` e `Query`.