Merge pull request #3 from koriym/cc

Add CacheControl

Author: koriym

src/CacheControl.php

@@ -0,0 +1,61 @@
+<?php
+
+/**
+ * This file is part of the Koriym.HttpConstants.
+ *
+ * @license http://opensource.org/licenses/MIT MIT
+ */
+namespace Koriym\HttpConstants;
+
+/**
+ * Cache control response directive
+ */
+final class CacheControl
+{
+    /**
+     * Indicates that the response may be cached by any cache.
+     */
+    const PUBLIC_ = 'public';
+
+    /**
+     * Indicates that the response is intended for a single user and must not be stored by a shared cache. A private cache may store the response.
+     */
+    const PRIVATE_ = 'private';
+
+    /**
+     * Specifies the maximum amount of time a resource will be considered fresh. Contrary to Expires, this directive is relative to the time of the request.
+     */
+    const MAX_AGE = 'max-age';
+
+    /**
+     * Takes precedence over max-age or the Expires header, but it only applies to shared caches (e.g., proxies) and is ignored by a private cache.
+     */
+    const S_MAX_AGE = 's-maxage';
+
+    /**
+     * Forces caches to submit the request to the origin server for validation before releasing a cached copy.
+     */
+    const NO_CACHE = 'no-cache';
+
+    /**
+     * The cache should not store anything about the client request or server response.
+     */
+    const NO_STORE = 'no-store';
+
+    /**
+     * The cache must verify the status of the stale resources before using it and expired ones should not be used.
+     */
+    const MUST_REVALIDATE = 'must-revalidate';
+
+    /**
+     * Same as must-revalidate, but it only applies to shared caches (e.g., proxies) and is ignored by a private cache.
+     */
+    const PROXY_REVALIDATE = 'proxy-revalidate';
+
+    /**
+     * Indicates that the response body will not change over time. (for web browser)
+     *
+     * @see http://bitsup.blogspot.com/2016/05/cache-control-immutable.html
+     */
+    const IMMUTABLE = 'immutable';
+}