headers = {
        "Origin": "https://localhost.tiangolo.com",
        "Access-Control-Request-Method": "GET",
        "Access-Control-Request-Headers": "X-Example",
    }
    response = client.options("/", headers=headers)
    assert response.status_code == 200, response.text
    assert response.text == "OK"
    assert (
        response.headers["access-control-allow-origin"]
        == "https://localhost.tiangolo.com"

# CORS (Cross-Origin Resource Sharing) { #cors-cross-origin-resource-sharing }

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">Понятие CORS или "Cross-Origin Resource Sharing"</a> относится к ситуациям, при которых запущенный в браузере фронтенд содержит JavaScript-код, который взаимодействует с бэкендом, находящимся на другом "источнике" ("origin").

## Источник { #origin }

    /**
     * Processes the CORS request by setting appropriate headers.
     *
     * @param origin the origin of the request
     * @param request the servlet request
     * @param response the servlet response
     */
    public abstract void process(String origin, ServletRequest request, ServletResponse response);

# CORS (Cross-Origin Resource Sharing) { #cors-cross-origin-resource-sharing }

<a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS" class="external-link" target="_blank">CORS ou "Cross-Origin Resource Sharing"</a> refere-se às situações em que um frontend rodando em um navegador possui um código JavaScript que se comunica com um backend, e o backend está em uma "origem" diferente do frontend.

## Origem { #origin }

中间件响应两种特定类型的 HTTP 请求……

### CORS 预检请求

这是些带有 `Origin` 和 `Access-Control-Request-Method` 请求头的 `OPTIONS` 请求。

在这种情况下，中间件将拦截传入的请求并进行响应，出于提供信息的目的返回一个使用了适当的 CORS headers 的 `200` 或 `400` 响应。

### 简单请求

任何带有 `Origin` 请求头的请求。在这种情况下，中间件将像平常一样传递请求，但是在响应中包含适当的 CORS headers。

## 更多信息

        final String origin = httpRequest.getHeader("Origin");
        if (StringUtil.isNotBlank(origin)) {
            if (logger.isDebugEnabled()) {
                logger.debug("HTTP Request: method={}", httpRequest.getMethod());
            }
            final CorsHandlerFactory factory = ComponentUtil.getCorsHandlerFactory();
            final CorsHandler handler = factory.get(origin);
            if (handler != null) {

```
curl http://minio1:9001/minio/health/cluster
HTTP/1.1 503 Service Unavailable
Accept-Ranges: bytes
Content-Length: 0
Server: MinIO
Vary: Origin
X-Amz-Bucket-Region: us-east-1
X-Minio-Write-Quorum: 3
X-Amz-Request-Id: 16239D6AB80EBECF
X-Xss-Protection: 1; mode=block
Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Cluster-readable probe

  @Nullable V removeSuccessor(N node);

  /**
   * Add {@code node} as a predecessor to the origin node. In the case of an undirected graph, it
   * also becomes a successor. Associates {@code value} with the edge connecting the two nodes.
   */
  void addPredecessor(N node, V value);

  /**
   * Add {@code node} as a successor to the origin node. In the case of an undirected graph, it also

## Джерело (Origin)

Джерело визначається комбінацією протоколу (`http`, `https`), домену (`myapp.com`, `localhost`, `localhost.tiangolo.com`), порту (`80`, `443`, `8080`).


Наприклад, такі адреси вважаються різними джерелами:

          git reset origin/master --hard

          ./gradlew wrapper --gradle-version=nightly
          ./gradlew wrapper

          if ! git diff --quiet; then
            ./gradlew -v
            VERSION=$(./gradlew -v | grep "Gradle" | cut -d' ' -f2)
            git add .
            git commit -m "Update Gradle wrapper to $VERSION"
            git push --force origin devprod/upgrade-to-latest-wrapper