1 files changed, 90 insertions, 0 deletions
diff --git a/library/Icinga/Application/Hook/ApplicationStateHook.php b/library/Icinga/Application/Hook/ApplicationStateHook.php
new file mode 100644
index 0000000..be973fe
--- /dev/null
+++ b/library/Icinga/Application/Hook/ApplicationStateHook.php
@@ -0,0 +1,90 @@
+<?php
+/* Icinga Web 2 | (c) 2018 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Application\Hook;
+
+use Icinga\Application\Hook;
+use Icinga\Application\Logger;
+
+/**
+ * Application state hook base class
+ */
+abstract class ApplicationStateHook
+{
+    const ERROR = 'error';
+
+    private $messages = [];
+
+    final public function hasMessages()
+    {
+        return ! empty($this->messages);
+    }
+
+    final public function getMessages()
+    {
+        return $this->messages;
+    }
+
+    /**
+     * Add an error message
+     *
+     * The timestamp of the message is used for deduplication and thus must refer to the time when the error first
+     * occurred. Don't use {@link time()} here!
+     *
+     * @param   string  $id         ID of the message. The ID must be prefixed with the module name
+     * @param   int     $timestamp  Timestamp when the error first occurred
+     * @param   string  $message    Error message
+     *
+     * @return  $this
+     */
+    final public function addError($id, $timestamp, $message)
+    {
+        $id = trim($id);
+        $timestamp = (int) $timestamp;
+
+        if (! strlen($id)) {
+            throw new \InvalidArgumentException('ID expected.');
+        }
+
+        if (! $timestamp) {
+            throw new \InvalidArgumentException('Timestamp expected.');
+        }
+
+        $this->messages[sha1($id . $timestamp)] = [self::ERROR, $timestamp, $message];
+
+        return $this;
+    }
+
+    /**
+     * Override this method in order to provide application state messages
+     */
+    abstract public function collectMessages();
+
+    final public static function getAllMessages()
+    {
+        $messages = [];
+
+        if (! Hook::has('ApplicationState')) {
+            return $messages;
+        }
+
+        foreach (Hook::all('ApplicationState') as $hook) {
+            /** @var self $hook */
+            try {
+                $hook->collectMessages();
+            } catch (\Exception $e) {
+                Logger::error(
+                    "Failed to collect messages from hook '%s'. An error occurred: %s",
+                    get_class($hook),
+                    $e
+                );
+            }
+
+            if ($hook->hasMessages()) {
+                $messages += $hook->getMessages();
+            }
+        }
+
+        return $messages;
+    }
+}