The middleware responds to two particular types of HTTP request...

### CORS preflight requests { #cors-preflight-requests }

These are any `OPTIONS` request with `Origin` and `Access-Control-Request-Method` headers.

In this case the middleware will intercept the incoming request and respond with appropriate CORS headers, and either a `200` or `400` response for informational purposes.

### Simple requests { #simple-requests }

	pluginAuthnServiceTotalRequestsMinuteMD  = NewCounterMD(pluginAuthnServiceTotalRequestsMinute, "When plugin authentication is configured, returns total requests count in the last full minute")
	sinceLastSyncMillisMD                    = NewCounterMD(sinceLastSyncMillis, "Time (in milliseconds) since last successful IAM data sync.")

     *
     * @param request The original HTTP servlet request
     * @param servletPath The custom servlet path for this web API request
     */
    public WebApiRequest(final HttpServletRequest request, final String servletPath) {
        super(request);
        this.servletPath = servletPath;
    }

    /**
     * Gets the servlet path for this request.

También defines de alguna manera en qué **momentos** tu aplicación enviará esas requests o eventos.

Y **tus usuarios** definen de alguna manera (por ejemplo en un panel web en algún lugar) el **URL** donde tu aplicación debería enviar esas requests.

   * the URL's host name. Note that concurrent requests to a single IP address may still exceed this
   * limit: multiple hostnames may share an IP address or be routed through the same HTTP proxy.
   *
   * If more than [maxRequestsPerHost] requests are in flight when this is invoked, those requests
   * will remain in flight.
   *
   * WebSocket connections to hosts **do not** count against this limit.
   */
  @get:Synchronized

				for b := range in {
					PutByteBuffer(b)
					got++
				}
				if got != requests {
					return NewRemoteErrf("wrong number of requests. want %d, got %d", requests, got)
				}
				return nil
			},

			Subroute:    "some-subroute",
			OutCapacity: 1,
			InCapacity:  1, // Only one message buffered.
		}))
		errFatal(err)
	}
	const payloadSize = 512

    /**
     * HTTP OPTIONS method constant used for CORS preflight requests.
     */
    protected static final String OPTIONS = "OPTIONS";

    @Override
    public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
            throws IOException, ServletException {
        final HttpServletRequest httpRequest = (HttpServletRequest) request;
        final String origin = httpRequest.getHeader("Origin");

 * that controls the interval between requests to the same host.
 * It uses a Guava Cache to store the last access time for each host.
 * The delayBeforeProcessing method is overridden to introduce a delay before processing a URL,
 * ensuring that requests to the same host are not made too frequently.

## `HTTPSRedirectMiddleware` { #httpsredirectmiddleware }

Impone que todas las requests entrantes deben ser `https` o `wss`.

Cualquier request entrante a `http` o `ws` será redirigida al esquema seguro.

{* ../../docs_src/advanced_middleware/tutorial001_py39.py hl[2,6] *}

## `TrustedHostMiddleware` { #trustedhostmiddleware }

///

### <a href="https://requests.readthedocs.io" class="external-link" target="_blank">Requests</a> { #requests }

**FastAPI** на самом деле не альтернатива **Requests**. Их области применения очень различны.

Обычно Requests используют даже внутри приложения FastAPI.

И всё же **FastAPI** во многом вдохновлялся Requests.