# 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:

    // Behold the weirdness!
    assertFalse(domain.publicSuffix().isPublicSuffix());
  }

  public void testPublicSuffixMultipleUnders() {
    // PSL has both *.uk and *.sch.uk; the latter should win.
    // See https://github.com/google/guava/issues/1176

    InternetDomainName domain = InternetDomainName.from("www.essex.sch.uk");
    assertTrue(domain.hasPublicSuffix());

      this.delegate = checkNotNull(delegate);
    }

    @Override
    @ParametricNullness
    public T get() {
      // Because Supplier is read-heavy, we use the "double-checked locking" pattern.
      if (delegate != null) {
        synchronized (lock) {
          if (delegate != null) {
            T t = delegate.get();
            value = t;
            delegate = null;
            return t;

        secondBarrier.await();
      }
    }

    @Override
    protected ScheduledExecutorService executor() {
      // use a bunch of threads so that weird overlapping schedules are more likely to happen.
      return newScheduledThreadPool(10);
    }

    @Override
    protected Scheduler scheduler() {
      return new CustomScheduler() {
        @Override

        secondBarrier.await();
      }
    }

    @Override
    protected ScheduledExecutorService executor() {
      // use a bunch of threads so that weird overlapping schedules are more likely to happen.
      return newScheduledThreadPool(10);
    }

    @Override
    protected Scheduler scheduler() {
      return new CustomScheduler() {
        @Override

Mais voici la partie intéressante. ✨

La manière « officielle » d'accéder à l'application serait via le proxy avec le préfixe de chemin que nous avons défini. Donc, comme on s'y attend, si vous essayez l'interface de documentation servie directement par Uvicorn, sans le préfixe de chemin dans l'URL, cela ne fonctionne pas, car elle s'attend à être accédée via le proxy.

    // exists and is a symlink to a directory... we'd like for this to succeed in that case.
    // (I'm kind of surprised that createDirectories would fail in that case; doesn't seem like
    // what you'd want to happen.)
    if (!Files.isDirectory(parent)) {
      Files.createDirectories(parent, attrs);
      if (!Files.isDirectory(parent)) {
        throw new IOException("Unable to create parent directories of " + path);
      }

	}

	// There is no way to handle errors here, so we panic the current goroutine
	// and the Metrics API handler returns a 500 HTTP status code. This should
	// normally not happen, and usually indicates a bug.
	logger.CriticalIf(GlobalContext, errors.Wrap(err, "failed to get metrics"))

	promMetrics := metricValues.ToPromMetrics(mg.CollectorPath.metricPrefix(),
		mg.ExtraLabels)

  }

  @Override
  public Collection<V> values() {
    return delegate.values();
  }

  @CanIgnoreReturnValue
  private <T> T checkValid(T t) {
    // a ClassCastException is what's supposed to happen!
    @SuppressWarnings("unchecked")
    K k = (K) t;
    int unused = comparator().compare(k, k);
    return t;
  }

  @Override
  public boolean equals(@Nullable Object obj) {

# Authentification HTTP Basic { #http-basic-auth }

Pour les cas les plus simples, vous pouvez utiliser l'authentification HTTP Basic.

Avec l'authentification HTTP Basic, l'application attend un en-tête contenant un nom d'utilisateur et un mot de passe.

Si elle ne le reçoit pas, elle renvoie une erreur HTTP 401 « Unauthorized ».

Et elle renvoie un en-tête `WWW-Authenticate` avec la valeur `Basic`, et un paramètre optionnel `realm`.