Issue #21: Session handler checking for memcached uses memcache funct…

…ions

This now uses memcached functions to determine if the session handler is
valid. Additionally it adds support for Moodle PHP7 error handling.

index.php

@@ -107,18 +107,33 @@ function failed($reason) {
     failed('sitedata not readable');
 }
 
+$sessionhandler = (property_exists($CFG, 'session_handler_class') && $CFG->session_handler_class === '\core\session\memcached');
+$savepath = property_exists($CFG, 'session_memcached_save_path');
 
-$sessionhandler = (property_exists($CFG, 'session_handler_class') && $CFG->session_handler_class == '\core\session\memcached');
+if ($sessionhandler && $savepath) {
+    require_once($CFG->libdir . '/classes/session/util.php');
+    $servers = \core\session\util::connection_string_to_memcache_servers($CFG->session_memcached_save_path);
+    try {
+        $memcached = new \Memcached();
+        $memcached->addServers($servers);
+        $stats = $memcached->getStats();
+        $memcached->quit();
 
-if ($sessionhandler) {
+        $addr = $servers[0][0];
+        $port = $servers[0][1];
+
+        if ($stats[$addr . ':' . $port]['uptime'] > 0) {
+            $status .= "session memcached OK<br>\n";
+        } else {
+            failed('sessions memcached');
+        }
 
-    $memcache = explode(':', $CFG->session_memcached_save_path );
-    try {
-        memcache_connect($memcache[0], $memcache[1], 3);
-        $status .= "session memcache OK<br>\n";
     } catch (Exception $e) {
-        failed('sessions memcache');
+        failed('sessions memcached');
+    } catch (Throwable $e) {
+        failed('sessions memcached');
     }
+
 }
 
 // Optionally check database configuration and access (slower).
@@ -137,6 +152,8 @@ function failed($reason) {
         }
     } catch (Exception $e) {
         failed('database error');
+    } catch (Throwable $e) {
+        failed('database error');
     }
 }