Mais dans des cas réels, lors de l'implémentation de la sécurité, vous tirerez davantage d'avantages en utilisant les [utilitaires de sécurité (chapitre suivant)](../security/index.md) intégrés.

///

## Gérer les erreurs et les valeurs de retour des dépendances { #dependencies-errors-and-return-values }

Vous pouvez utiliser les mêmes *fonctions* de dépendance que d'habitude.

app.add_middleware(UnicornMiddleware, some_config="rainbow")
```

`app.add_middleware()` reçoit une classe de middleware en premier argument, ainsi que tout argument supplémentaire à transmettre au middleware.

## Utiliser les middlewares intégrés { #integrated-middlewares }

**FastAPI** inclut plusieurs middlewares pour des cas d'usage courants ; voyons comment les utiliser.

/// note | Détails techniques

        LeaseEntry entry = leases.get(key);
        if (entry != null) {
            log.info("Handling lease break for {} from state 0x{} to 0x{}", key, Integer.toHexString(entry.getLeaseState()),
                    Integer.toHexString(newState));

            entry.setBreaking(true);
            int oldState = entry.getLeaseState();
            entry.updateState(newState);

        activeMinPort = getInitParameter("activeMinPort", -1, Integer.class);
        activeMaxPort = getInitParameter("activeMaxPort", -1, Integer.class);
        autodetectEncoding = getInitParameter("autodetectEncoding", true, Boolean.class);
        connectTimeout = getInitParameter("connectTimeout", 0, Integer.class);
        dataTimeout = getInitParameter("dataTimeout", -1, Integer.class);

   * properties of the multimap, such as iteration order, are left intact. For example, the code:
   *
   * {@snippet :
   * Multimap<String, Integer> multimap =
   *     ImmutableSetMultimap.of("a", 2, "b", -3, "b", -3, "a", 4, "c", 6);
   * Function<Integer, String> square = in -> Integer.toString(in * in);
   * Multimap<String, String> transformed = Multimaps.transformValues(multimap, square);
   * System.out.println(transformed);

   * properties of the multimap, such as iteration order, are left intact. For example, the code:
   *
   * {@snippet :
   * Multimap<String, Integer> multimap =
   *     ImmutableSetMultimap.of("a", 2, "b", -3, "b", -3, "a", 4, "c", 6);
   * Function<Integer, String> square = in -> Integer.toString(in * in);
   * Multimap<String, String> transformed = Multimaps.transformValues(multimap, square);
   * System.out.println(transformed);

  }

  @Generates
  int generateInt() {
    return freshness.get();
  }

  @SuppressWarnings("removal") // b/321209431 -- maybe just use valueOf here?
  @Generates
  Integer generateInteger() {
    return new Integer(generateInt());
  }

  @Generates
  long generateLong() {
    return generateInt();
  }

  @SuppressWarnings("removal") // b/321209431 -- maybe just use valueOf here?

   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

  CollectionSize(int numElements) {
    this.implied = emptySet();
    this.numElements = numElements;
  }

  CollectionSize(Feature<? super Collection>... implied) {

   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

  CollectionSize(int numElements) {
    this.implied = emptySet();
    this.numElements = numElements;
  }

  CollectionSize(Feature<? super Collection>... implied) {

        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.CommonServerMessageBlockRequest#getOverrideTimeout()
     */
    @Override
    public Integer getOverrideTimeout() {
        return null;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.internal.CommonServerMessageBlockRequest#allowChain(jcifs.internal.CommonServerMessageBlockRequest)
     */