1 files changed, 118 insertions, 0 deletions
diff --git a/library/Icingadb/Common/Macros.php b/library/Icingadb/Common/Macros.php
new file mode 100644
index 0000000..733c116
--- /dev/null
+++ b/library/Icingadb/Common/Macros.php
@@ -0,0 +1,118 @@
+<?php
+
+/* Icinga DB Web | (c) 2021 Icinga GmbH | GPLv2 */
+
+namespace Icinga\Module\Icingadb\Common;
+
+use Icinga\Application\Logger;
+use Icinga\Module\Icingadb\Model\Host;
+use ipl\Orm\Model;
+use ipl\Orm\Query;
+use ipl\Orm\ResultSet;
+
+use function ipl\Stdlib\get_php_type;
+
+trait Macros
+{
+    /**
+     * Get the given string with macros being resolved
+     *
+     * @param string $input  The string in which to look for macros
+     * @param Model  $object The host or service used to resolve the macros
+     *
+     * @return string
+     */
+    public function expandMacros(string $input, Model $object): string
+    {
+        if (preg_match_all('@\$([^\$\s]+)\$@', $input, $matches)) {
+            foreach ($matches[1] as $key => $value) {
+                $newValue = $this->resolveMacro($value, $object);
+                if ($newValue !== $value) {
+                    $input = str_replace($matches[0][$key], $newValue, $input);
+                }
+            }
+        }
+
+        return $input;
+    }
+
+    /**
+     * Resolve a macro based on the given object
+     *
+     * @param string $macro  The macro to resolve
+     * @param Model  $object The host or service used to resolve the macros
+     *
+     * @return string
+     */
+    public function resolveMacro(string $macro, Model $object): string
+    {
+        if ($object instanceof Host) {
+            $objectType = 'host';
+        } else {
+            $objectType = 'service';
+        }
+
+        $path = null;
+        $macroType = $objectType;
+        $isCustomVar = false;
+        if (preg_match('/^((host|service)\.)?vars\.(.+)/', $macro, $matches)) {
+            if (! empty($matches[2])) {
+                $macroType = $matches[2];
+            }
+
+            $path = $matches[3];
+            $isCustomVar = true;
+        } elseif (preg_match('/^(\w+)\.(.+)/', $macro, $matches)) {
+            $macroType = $matches[1];
+            $path = $matches[2];
+        }
+
+        try {
+            if ($path !== null) {
+                if ($macroType !== $objectType) {
+                    $value = $object->$macroType;
+                } else {
+                    $value = $object;
+                }
+
+                $properties = explode('.', $path);
+
+                do {
+                    $column = array_shift($properties);
+                    if ($value instanceof Query || $value instanceof ResultSet || is_array($value)) {
+                        Logger::debug(
+                            'Failed to resolve property "%s" on a "%s" type.',
+                            $isCustomVar ? 'vars' : $column,
+                            get_php_type($value)
+                        );
+                        $value = null;
+                        break;
+                    }
+
+                    if ($isCustomVar) {
+                        $value = $value->vars[$path];
+                        break;
+                    }
+
+                    $value = $value->$column;
+                } while (! empty($properties) && $value !== null);
+            } else {
+                $value = $object->$macro;
+            }
+        } catch (\Exception $e) {
+            $value = null;
+            Logger::debug('Unable to resolve macro "%s". An error occurred: %s', $macro, $e);
+        }
+
+        if ($value instanceof Query || $value instanceof ResultSet || is_array($value)) {
+            Logger::debug(
+                'It is not allowed to use "%s" as a macro which produces a "%s" type as a result.',
+                $macro,
+                get_php_type($value)
+            );
+            $value = null;
+        }
+
+        return $value !== null ? $value : $macro;
+    }
+}