1 files changed, 38 insertions, 0 deletions

diff --git a/application/feed/Cache.php b/application/feed/Cache.php
new file mode 100644
index 00000000..e5d43e61
--- /dev/null
+++ b/application/feed/Cache.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * Cache utilities
+ */
+
+/**
+ * Purges all cached pages
+ *
+ * @param string $pageCacheDir page cache directory
+ *
+ * @return mixed an error string if the directory is missing
+ */
+function purgeCachedPages($pageCacheDir)
+{
+    if (! is_dir($pageCacheDir)) {
+        $error = sprintf(t('Cannot purge %s: no directory'), $pageCacheDir);
+        error_log($error);
+        return $error;
+    }
+
+    array_map('unlink', glob($pageCacheDir.'/*.cache'));
+}
+
+/**
+ * Invalidates caches when the database is changed or the user logs out.
+ *
+ * @param string $pageCacheDir page cache directory
+ */
+function invalidateCaches($pageCacheDir)
+{
+    // Purge cache attached to session.
+    if (isset($_SESSION['tags'])) {
+        unset($_SESSION['tags']);
+    }
+
+    // Purge page cache shared by sessions.
+    purgeCachedPages($pageCacheDir);
+}