monitoring/hooks: Add TicketHook::createLinks()

Instead of calling preg_replace_callback w/o error handling in our view scripts, TicketHook::createLinks() will take care of that.

refs #9611

library/Icinga/Web/Hook/TicketHook.php

@@ -3,6 +3,12 @@
 
 namespace Icinga\Web\Hook;
 
+use ErrorException;
+use Exception;
+use Icinga\Application\Icinga;
+use Icinga\Application\Logger;
+use Icinga\Exception\IcingaException;
+
 /**
  * Icinga Web Ticket Hook base class
  *
@@ -15,6 +21,13 @@ namespace Icinga\Web\Hook;
  */
 abstract class TicketHook
 {
+    /**
+     * Last error, if any
+     *
+     * @var string|null
+     */
+    protected $lastError;
+
     /**
      * Constructor must live without arguments right now
      *
@@ -28,15 +41,91 @@ abstract class TicketHook
 
     /**
      * Overwrite this function if you want to do some initialization stuff
-     *
-     * @return void
      */
     protected function init()
     {
     }
 
+    /**
+     * Set the hook as failed w/ the given message
+     *
+     * @param   string  $message    Error message or error format string
+     * @param   mixed   ...$arg     Format string argument
+     */
+    private function fail($message)
+    {
+        $args = array_slice(func_get_args(), 1);
+        $lastError = vsprintf($message, $args);
+        Logger::debug($lastError);
+        $this->lastError = $lastError;
+    }
+
+    /**
+     * Get the last error, if any
+     *
+     * @return string|null
+     */
+    public function getLastError()
+    {
+        return $this->lastError;
+    }
+
+    /**
+     * Get the pattern
+     *
+     * @return string
+     */
     abstract public function getPattern();
 
+    /**
+     * Create a link for each matched element in the subject text
+     *
+     * @param   array $match    Array of matched elements according to {@link getPattern()}
+     *
+     * @return  string          Replacement string
+     */
     abstract public function createLink($match);
 
+    /**
+     * Create links w/ {@link createLink()} in the given text that matches to the subject from {@link getPattern()}
+     *
+     * In case of errors a debug message is recorded to the log and any subsequent call to {@link createLinks()} will
+     * be a no-op.
+     *
+     * @param   string $text
+     *
+     * @return  string
+     */
+    final public function createLinks($text)
+    {
+        if ($this->lastError !== null) {
+            return $text;
+        }
+
+        try {
+            $pattern = $this->getPattern();
+        } catch (Exception $e) {
+            $this->fail('Can\'t create ticket links: Retrieving the pattern failed: %s', IcingaException::describe($e));
+            return $text;
+        }
+        if (empty($pattern)) {
+            $this->fail('Can\'t create ticket links: Pattern is empty');
+            return $text;
+        }
+        try {
+            $text = preg_replace_callback(
+                $pattern,
+                array($this, 'createLink'),
+                $text
+            );
+        } catch (ErrorException $e) {
+            $this->fail('Can\'t create ticket links: Pattern is invalid: %s', IcingaException::describe($e));
+            return $text;
+        } catch (Exception $e) {
+            $this->fail('Can\'t create ticket links: %s', IcingaException::describe($e));
+            return $text;
+        }
+
+        return $text;
+    }
 }