# CORS (Cross-Origin Resource Sharing)

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS or "Cross-Origin Resource Sharing"</a> refers to the situations when a frontend running in a browser has JavaScript code that communicates with a backend, and the backend is in a different "origin" than the frontend.

## Origin

Sa(e,a,t,s,!1)}M.createFromInputFallback=t("value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.",function(e){e._d=new Date(e._i+(e._useUTC?" UTC":""))}),M.ISO_8601=function(){},M.RFC_2822=function(){};var ja=t("moment().min is deprecated, use moment.max instead. http://momentjs...

		c.Compiler = build.Default.Compiler
	}

	walkers := make([]*Walker, len(contexts))
	var wg sync.WaitGroup
	for i, context := range contexts {
		i, context := i, context
		wg.Add(1)
		go func() {
			defer wg.Done()
			walkers[i] = NewWalker(context, filepath.Join(testenv.GOROOT(t), "src"))
		}()
	}
	wg.Wait()

	var featureCtx = make(map[string]map[string]bool) // feature -> context name -> true

	if debugNoExit {
		freeze := func(_ int) {
			// Infinite blocking op
			<-make(chan struct{})
		}

		// Override the logger os.Exit()
		logger.ExitFunc = freeze

		defer func() {
			if err := recover(); err != nil {
				fmt.Println("panic:", err)
				fmt.Println("")
				fmt.Println(string(debug.Stack()))
			}
			freeze(-1)
		}()
	}

		closeWithErr: rb.CloseWithError,
		h:            h,
		shardSize:    shardSize,
		canClose:     &sync.WaitGroup{},
		byteBuf:      buf,
	}
	bw.canClose.Add(1)
	go func() {
		defer bw.canClose.Done()

		totalFileSize := int64(-1) // For compressed objects length will be unknown (represented by length=-1)
		if length != -1 {

			// are provided, we will not return bucket metrics.
			if bmg, ok := h.metricsData.bucketMGMap[collectorPath]; ok {
				if len(buckets) == 0 {
					continue
				}
				unLocker := bmg.LockAndSetBuckets(buckets)
				defer unLocker()
			}
			gatherers = append(gatherers, gatherer)
		}
	}

	if len(gatherers) == 0 {
		return notFoundHandler
	}

	return promhttp.HandlerFor(prometheus.Gatherers(gatherers), h.opts)

func (m metacache) keepAlive(ctx context.Context, rpc *peerRESTClient) {
	// we intentionally operate on a copy of m, so we can update without locks.
	t := time.NewTicker(metacacheMaxClientWait / 10)
	defer t.Stop()
	for {
		select {
		case <-ctx.Done():
			// Request is done, stop updating.
			return
		case <-t.C:
			m.lastHandout = time.Now()

			writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
			return
		}
	}

	// Initialize a zip writer which will provide a zipped content
	// of bucket metadata
	zipWriter := zip.NewWriter(w)
	defer zipWriter.Close()

	rawDataFn := func(r io.Reader, filename string, sz int) {
		header, zerr := zip.FileInfoHeader(dummyFileInfo{
			name:    filename,
			size:    int64(sz),
			mode:    0o600,

   *     different kind of exception, that exception itself. To avoid hiding bugs and other
   *     unrecoverable errors, callers should prefer more specific types, avoiding {@code
   *     Throwable.class} in particular.
   * @param fallback the {@link Function} to be called if the input fails with the expected

 *   </li>
 * <li>a hyphen usually precedes a qualifier, and is always less important than digits/number, for example
 *   {@code 1.0.RC2 < 1.0-RC3 < 1.0.1}; but prefer {@code 1.0.0-RC1} over {@code 1.0.0.RC1}, and more
 *   generally: {@code 1.0.X2 < 1.0-X3 < 1.0.1} for any string {@code X}; but prefer {@code 1.0.0-X1}
 *   over {@code 1.0.0.X1}.</li>
 * </ul>
 *