FOSHttpCache

• Added: ClearCapable to clear the whole cache in one efficient call. Currently
  supported only by the Symfony HttpCache.
• Allow installing with Httplug 2.0 / PSR-18.

Symfony HttpCache

• Fixed: Avoid regression of 2.5.3: If there are no messages to be dispatched,
  do not throw an exception if the HttpCache is not set.

Symfony HttpCache

• Fixed: Handle HttpCache not available in KernelDispatcher and fix return
  type annotations - if HttpCache is not set, it can't be returned.

Varnish

• Fixed: Remove the xkey header in vcl_deliver if we are not in debug mode
• Do not cleanup the Vary header and keep the user context hash if we are in debug mode

Cache Tagging

• Fixed: Clear the ResponseTagger after we tagged a response. Usually PHP uses
  a new instance for every request. But for example the hash lookup when using
  Symfony HttpCache does two requests in the same PHP process.

• Fixed: MaxHeaderValueLengthFormatter::getTagsHeaderName now actually returns the value.

Cache Tagging

• Added: MaxHeaderValueLengthFormatter to allow splitting cache tag headers into
  multiple headers.

Symfony HttpCache

• Have cache invalidator check for presence of Psr6Store for a better guess
  whether the cache really is TagCapable or not.

Symfony

• Added: CleanupCacheTagsListener to remove the cache tags header from the final
  response that is sent to the client. Add this listener to your cache kernel.

Tagging

• Improved: The ResponseTagger does now remove duplicate tags.

Varnish

• Fixed: Do not preg_quote tags when using xkey. Quoting is only used for BAN
  requests that expect a regular expression. This bug only affected you if you
  use xkey and used characters in your tags that are changed by preg_quote.

ProxyClient

• The HttpProxyClient now accepts an instance of the new Dispatcher interface
  instead of the concrete HttpDispatcher, allowing for more flexibility.

Symfony

• Introduced a new KernelDispatcher for the Symfony proxy that calls the application
  kernel directly instead of executing a full HTTP request.

• more friendly VCL for when std is used in main VCL

Varnish

• Added support for the more efficient xkey cache tag system. BAN remains the
  default cache tagging system, but if you can install the varnish modules in
  your system, it is recommended to update to xkey.
• No inline C is needed for the custom TTL header with Varnish 4 or better. use
  std.duration() instead.

Symfony user context

• You can now also specify which headers are used for
  authentication to detect anonymous requests. By default, the headers are the
  previously hardcoded Authorization, HTTP_AUTHORIZATION and
  PHP_AUTH_USER.

• Symfony user context: You can now also specify which headers are used for
  authentication to detect anonymous requests. By default, the headers are the
  previously hardcoded Authorization, HTTP_AUTHORIZATION and
  PHP_AUTH_USER.

• Fixed bug in Symfony tag invalidation.
  Do not check if host is missing in request creation.

• Fixed issue with detection if toflar psr6 store is available

• Fix varnish tag invalidation regular expression to avoid matching on tag endings

• Support Symfony 4.

Testing

• Upgraded phpunit to 5.7 / 6. If you use anything from the
  FOS\HttpCache\Test namespace you need to update your project to use
  PHPUnit 6 (or 5.7, if you are using PHP 5.6).

Symfony HttpCache

• Cache tagging supprt for Symfony HttpCache

  Added a PurgeTagsListener for tag based invalidation with the Symfony
  HttpCache reverse caching proxy. This requires the newly created
  Toflar Psr6Store
  built on PSR-6 cache and supporting pruning expired cache entries.

• Using Request::isMethodCacheable rather than Request::isMethodSafe to
  correctly handle OPTIONS and TRACE requests.

• Avoid problems with http_method_override
  See http://symfony.com/doc/current/reference/configuration/framework.html#configuration-framework-http-method-override

Support PHP 7.2

• Avoid a warning with PHP 7.2

• Ban requests now work even when no base URI is configured.