From 4a71c00034f0b3def02eee5de0728bb048b627bf Mon Sep 17 00:00:00 2001
From: David Buchmann <david.buchmann@liip.ch>
Date: Wed, 27 Sep 2017 17:27:31 +0200
Subject: [PATCH] rename purge_tags_header config to cache_tags_header

---
 README.md         | 11 ++++++++++-
 src/Psr6Store.php | 16 +++++++++-------
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 6c88c30..3984034 100644
--- a/README.md
+++ b/README.md
@@ -88,11 +88,20 @@ passing an array of `$options` in the constructor:
   **Type**: `int`
   **Default**: `500`
 
-* **purge_tags_header**: The HTTP header name used to check for tags
+* **cache_tags_header**: The HTTP header name used to check for tags
 
   **Type**: `string`
   **Default**: `Cache-Tags`
 
+### Cache Tagging
+
+Tag cache entries by adding a response header with the tags as a comma 
+separated value. By default, that header is called `Cache-Tags`, this can be
+overwritten in `cache_tags_header`.
+
+To invalidate tags, call the method `Psr6Store::invalidateTags` or use the
+`PurgeTagsListener` from the [FOSHttpCache][3] library to handle tag 
+invalidation requests.
 
 ### WARNING
 
diff --git a/src/Psr6Store.php b/src/Psr6Store.php
index b7168ee..37af48a 100644
--- a/src/Psr6Store.php
+++ b/src/Psr6Store.php
@@ -94,7 +94,8 @@ final class Psr6Store implements StoreInterface
      *                      Type: int
      *                      Default: 500
      *
-     * - purge_tags_header: The HTTP header name used to check for tags
+     * - cache_tags_header: Name of HTTP header containing a comma separated
+     *                      list of tags to tag the response with.
      *
      *                      Type: string
      *                      Default: Cache-Tags
@@ -111,8 +112,8 @@ public function __construct(array $options = [])
         $resolver->setDefault('prune_threshold', 500)
             ->setAllowedTypes('prune_threshold', 'int');
 
-        $resolver->setDefault('purge_tags_header', 'Cache-Tags')
-            ->setAllowedTypes('purge_tags_header', 'string');
+        $resolver->setDefault('cache_tags_header', 'Cache-Tags')
+            ->setAllowedTypes('cache_tags_header', 'string');
 
         $resolver->setDefault('cache', function (Options $options) {
             if (!isset($options['cache_directory'])) {
@@ -231,8 +232,8 @@ public function write(Request $request, Response $response)
 
         // Tags
         $tags = [];
-        if ($response->headers->has($this->options['purge_tags_header'])) {
-            $tags = explode(',', $response->headers->get($this->options['purge_tags_header']));
+        if ($response->headers->has($this->options['cache_tags_header'])) {
+            $tags = explode(',', $response->headers->get($this->options['cache_tags_header']));
         }
 
         // Prune expired entries on file system if needed
@@ -356,13 +357,14 @@ public function cleanup()
 
     /**
      * Remove/Expire cache objects based on cache tags.
-     * Returns true on success and false otherwise.
+     *
+     * The tags are set from the header configured in cache_tags_header.
      *
      * @param array $tags Tags that should be removed/expired from the cache
      *
      * @throws \RuntimeException if incompatible cache adapter provided
      *
-     * @return bool
+     * @return bool true on success, false otherwise
      */
     public function invalidateTags(array $tags)
     {