minor #8682 Updated http_cache/* articles to Symfony 4 (javiereguiluz, weaverryan)

This PR was merged into the 4.0 branch.

Discussion
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Updated http_cache/* articles to Symfony 4

I have a question about the old `AppCache` class. I've moved to `src/AppCache.php` under `App` namespace. Is that correct? And also: should we rename it to `Cache` or `KernelCache` or something else? AppCache was great when we had AppKernel ... but now we have just Kernel.

Commits
-------

1e75772 Merge branch '4.0' into update_http_cache
664f280 Merge branch '4.0' into update_http_cache
d512875 Updated http_cache/* articles to Symfony 4

Author: weaverryan

http_cache.rst

@@ -125,6 +125,8 @@ finely tuned via a set of options you can set by overriding the
 method::
 
     // src/CacheKernel.php
+    namespace App;
+
     use Symfony\Bundle\FrameworkBundle\HttpCache\HttpCache;
 
     class CacheKernel extends HttpCache
@@ -141,10 +143,9 @@ method::
 For a full list of the options and their meaning, see the
 :method:`HttpCache::__construct() documentation <Symfony\\Component\\HttpKernel\\HttpCache\\HttpCache::__construct>`.
 
-When you're in debug mode (either because your booting a ``debug`` kernel, like
-in ``index.php`` *or* you manually set the ``debug`` option to true), Symfony
-automatically adds an ``X-Symfony-Cache`` header to the response. Use this to get
-information about cache hits and misses.
+When you're in debug mode (the second argument of ``Kernel`` constructor in the
+front controller is ``true``), Symfony automatically adds an ``X-Symfony-Cache``
+header to the response. Use this to get information about cache hits and misses.
 
 .. _http-cache-symfony-versus-varnish:
 
@@ -218,7 +219,7 @@ The *easiest* way to cache a response is by caching it for a specific amount of
     use Symfony\Component\HttpFoundation\Response;
     // ...
 
-    public function indexAction()
+    public function index()
     {
         // somehow create a Response object, like by rendering a template
         $response = $this->render('blog/index.html.twig', []);

http_cache/esi.rst

@@ -62,14 +62,14 @@ First, to use ESI, be sure to enable it in your application configuration:
 
     .. code-block:: yaml
 
-        # app/config/config.yml
+        # config/packages/framework.yaml
         framework:
             # ...
             esi: { enabled: true }
 
     .. code-block:: xml
 
-        <!-- app/config/config.xml -->
+        <!-- config/packages/framework.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/symfony"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -87,7 +87,7 @@ First, to use ESI, be sure to enable it in your application configuration:
 
     .. code-block:: php
 
-        // app/config/config.php
+        // config/packages/framework.php
         $container->loadFromExtension('framework', array(
             // ...
             'esi' => array('enabled' => true),
@@ -104,7 +104,7 @@ independent of the rest of the page.
     // ...
     class DefaultController extends Controller
     {
-        public function aboutAction()
+        public function about()
         {
             $response = $this->render('static/about.html.twig');
             // set the shared max age - which also marks the response as public
@@ -195,7 +195,7 @@ of the master page.
     // ...
     class NewsController extends Controller
     {
-        public function latestAction($maxPerPage)
+        public function latest($maxPerPage)
         {
             // ...
             $response->setSharedMaxAge(60);
@@ -220,14 +220,14 @@ that must be enabled in your configuration:
 
     .. code-block:: yaml
 
-        # app/config/config.yml
+        # config/packages/framework.yaml
         framework:
             # ...
             fragments: { path: /_fragment }
 
     .. code-block:: xml
 
-        <!-- app/config/config.xml -->
+        <!-- config/packages/framework.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
         <container xmlns="http://symfony.com/schema/dic/services"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
@@ -245,7 +245,7 @@ that must be enabled in your configuration:
 
     .. code-block:: php
 
-        // app/config/config.php
+        // config/packages/framework.php
         $container->loadFromExtension('framework', array(
             // ...
             'fragments' => array('path' => '/_fragment'),

http_cache/validation.rst

@@ -66,7 +66,7 @@ To see a simple implementation, generate the ETag as the md5 of the content::
 
     class DefaultController extends Controller
     {
-        public function homepageAction(Request $request)
+        public function homepage(Request $request)
         {
             $response = $this->render('static/homepage.html.twig');
             $response->setEtag(md5($response->getContent()));
@@ -131,7 +131,7 @@ header value::
 
     class ArticleController extends Controller
     {
-        public function showAction(Article $article, Request $request)
+        public function show(Article $article, Request $request)
         {
             $author = $article->getAuthor();
 
@@ -190,7 +190,7 @@ exposing a simple and efficient pattern::
 
     class ArticleController extends Controller
     {
-        public function showAction($articleSlug, Request $request)
+        public function show($articleSlug, Request $request)
         {
             // Get the minimum information to compute
             // the ETag or the Last-Modified value