# CORS (Cross-Origin Resource Sharing)

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">Понятие CORS или "Cross-Origin Resource Sharing"</a> относится к ситуациям, при которых запущенный в браузере фронтенд содержит JavaScript-код, который взаимодействует с бэкендом, находящимся на другом "источнике" ("origin").

## Источник

            return "Unknown";
        }
        Throwable target = t;
        if (target.getCause() == null) {
            return target.getClass().getSimpleName() + "[" + target.getMessage() + "]";
        }
        final StringBuilder sb = new StringBuilder();
        while (target != null) {
            sb.append(target.getClass().getSimpleName());
            if (target.getMessage() != null) {
                sb.append("[");

特别是，你可以直接使用 <a href="https://anyio.readthedocs.io/en/stable/" class="external-link" target="_blank">AnyIO</a> 来处理高级的并发用例，这些用例需要在自己的代码中使用更高级的模式。

Como o **FastAPI** é na verdade o **Starlette** por baixo, com camadas de diversas funcionalidades por cima, você pode utilizar o objeto <a href="https://www.starlette.io/requests/" class="external-link" target="_blank">`Request`</a> do Starlette diretamente quando precisar.

    this.element = Preconditions.checkNotNull(element);
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public boolean contains(@CheckForNull Object target) {
    return element.equals(target);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return singletonIterator(element);
  }

  @Override
  public ImmutableList<E> asList() {

/// info

To receive uploaded files and/or form data, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

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

///

## Import `File` and `Form`

# The -vv causes dist to print each build command as it runs.
# go tool dist clean cleans all directories, not just this one,
# but it's as close as we can get.

# Default target (first).
install:
	go tool dist install -v

verbose:
	go tool dist install -vv

clean:

    * Você também pode adicionar [dependências de `Segurança` com `scopes`](../advanced/security/oauth2-scopes.md){.internal-link target=_blank}.

/// tip | "Dica"

/// info | Informação

Para saber mais sobre o <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic, verifique a sua documentação</a>.

///

O **FastAPI** é todo baseado em Pydantic.

Você verá muito mais disso na prática no [Tutorial - Guia do usuário](tutorial/index.md){.internal-link target=_blank}.

/// tip | Dica

Python'un önceki sürümlerinde, threadlerı veya <a href="https://www.gevent.org/" class="external-link" target="_blank">Gevent</a> kullanıyor olabilirdin. Ancak kodu anlamak, hata ayıklamak ve düşünmek çok daha karmaşık olurdu.

NodeJS / Browser JavaScript'in önceki sürümlerinde, "callback" kullanırdınız. Bu da <a href="http://callbackhell.com/" class="external-link" target="_blank">callbacks cehennemine</a> yol açar.

## Coroutine'ler