## O `OAuth2PasswordBearer` do **FastAPI** { #fastapis-oauth2passwordbearer }

O **FastAPI** fornece várias ferramentas, em diferentes níveis de abstração, para implementar essas funcionalidades de segurança.

Neste exemplo, vamos usar **OAuth2**, com o fluxo **Password**, usando um token **Bearer**. Fazemos isso usando a classe `OAuth2PasswordBearer`.

/// info | Informação

func (r *Reader) Size() int64 { return int64(len(r.s)) }

// Read implements the [io.Reader] interface.
func (r *Reader) Read(b []byte) (n int, err error) {
	if r.i >= int64(len(r.s)) {
		return 0, io.EOF
	}
	r.prevRune = -1
	n = copy(b, r.s[r.i:])
	r.i += int64(n)
	return
}

// ReadAt implements the [io.ReaderAt] interface.
func (r *Reader) ReadAt(b []byte, off int64) (n int, err error) {

	return
}

// DecodeMsg implements msgp.Decodable
func (z *BatchJobSize) DecodeMsg(dc *msgp.Reader) (err error) {
	{
		var zb0001 int64
		zb0001, err = dc.ReadInt64()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		(*z) = BatchJobSize(zb0001)
	}
	return
}

// EncodeMsg implements msgp.Encodable

	Destination     reflect.Value
	Context         context.Context
	value           interface{}
	fieldValue      interface{}
}

// Scan implements sql.Scanner interface
func (s *serializer) Scan(value interface{}) error {
	s.value = value
	return nil
}

// Value implements driver.Valuer interface
func (s serializer) Value() (driver.Value, error) {
	return s.SerializeValuer.Value(s.Context, s.Field, s.Destination, s.fieldValue)

                }
              },
              isParallel)
          .onClose(stream::close);
    }
    final class Splitr extends MapWithIndexSpliterator<Spliterator<T>, R, Splitr>
        implements Consumer<T> {
      @Nullable T holder;

      Splitr(Spliterator<T> splitr, long index) {
        super(splitr, index);
      }

      @Override
      public void accept(@ParametricNullness T t) {

 *
 * @author Kevin Bourrillion
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989
@GwtCompatible
abstract class Cut<C extends Comparable> implements Comparable<Cut<C>>, Serializable {
  final C endpoint;

  Cut(C endpoint) {
    this.endpoint = endpoint;
  }

  abstract boolean isLessThan(C value);

  abstract BoundType typeAsLowerBound();

        Iterable<? extends Node> getCommentText();
    }

    private static class NoOpCommentSource implements CommentSource {
        @Override
        public List<? extends Node> getCommentText() {
            throw new UnsupportedOperationException();
        }
    }

    private class InheritedPropertyCommentSource implements CommentSource {
        private final PropertyMetaData propertyMetaData;

	return
}

// DecodeMsg implements msgp.Decodable
func (z *dataUsageHash) DecodeMsg(dc *msgp.Reader) (err error) {
	{
		var zb0001 string
		zb0001, err = dc.ReadString()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		(*z) = dataUsageHash(zb0001)
	}
	return
}

// EncodeMsg implements msgp.Encodable

Mas ele fornece as ferramentas para simplificar o processo o máximo possível, sem comprometer a flexibilidade, robustez ou segurança.

E você pode usar e implementar protocolos padrão seguros, como o OAuth2, de uma maneira relativamente simples.

        assertThat(expected).hasMessageThat().contains(message);
      }
      return;
    }
    fail("expected failure not reported");
  }

  private class ForwardingRunnable implements Runnable {

    private final Runnable runnable;

    ForwardingRunnable(Runnable runnable) {
      this.runnable = runnable;
    }

    @Override
    public void run() {
      runnable.run();