lib: Add UserGroupBackend as base class and factory for user group backends

library/Icinga/Authentication/UserGroupBackend.php

@@ -0,0 +1,113 @@
+<?php
+// {{{ICINGA_LICENSE_HEADER}}}
+// {{{ICINGA_LICENSE_HEADER}}}}
+
+namespace Icinga\Authentication;
+
+use Zend_Config;
+use Icinga\Authentication\Backend\DbUserGroupBackend;
+use Icinga\Authentication\Backend\IniUserGroupBackend;
+use Icinga\Data\ResourceFactory;
+use Icinga\Exception\ConfigurationError;
+use Icinga\Exception\IcingaException;
+use Icinga\User;
+
+/**
+ * Base class and factory for user group backends
+ */
+abstract class UserGroupBackend
+{
+    /**
+     * Name of the backend
+     *
+     * @var string
+     */
+    protected $name;
+
+    /**
+     * Set the backend name
+     *
+     * @param   string $name
+     *
+     * @return  $this
+     */
+    public function setName($name)
+    {
+        $this->name = (string) $name;
+        return $this;
+    }
+
+    /**
+     * Get the backend name
+     *
+     * @return string
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    /**
+     * Create a user group backend
+     *
+     * @param   string      $name
+     * @param   Zend_Config $backendConfig
+     *
+     * @return DbUserGroupBackend|IniUserGroupBackend
+     * @throws ConfigurationError If the backend configuration is invalid
+     */
+    public static function create($name, Zend_Config $backendConfig)
+    {
+        if ($backendConfig->name !== null) {
+            $name = $backendConfig->name;
+        }
+        if (($backendType = $backendConfig->backend) === null) {
+            throw new ConfigurationError(
+                'Configuration for user group backend \'%s\' is missing the \'backend\' directive',
+                $name
+            );
+        }
+        $backendType = strtolower($backendType);
+        if (($resourceName = $backendConfig->resource) === null) {
+            throw new ConfigurationError(
+                'Configuration for user group backend \'%s\' is missing the \'resource\' directive',
+                $name
+            );
+        }
+        $resourceName = strtolower($resourceName);
+        try {
+            $resource = ResourceFactory::create($resourceName);
+        } catch (IcingaException $e) {
+            throw new ConfigurationError(
+                'Can\'t create user group backend \'%s\'. An exception was thrown: %s',
+                $resourceName,
+                $e
+            );
+        }
+        switch ($backendType) {
+            case 'db':
+                $backend = new DbUserGroupBackend($resource);
+                break;
+            case 'ini':
+                $backend = new IniUserGroupBackend($resource);
+                break;
+            default:
+                throw new ConfigurationError(
+                    'Can\'t create user group backend \'%s\'. Invalid backend type \'%s\'.',
+                    $name,
+                    $backendType
+                );
+        }
+        $backend->setName($name);
+        return $backend;
+    }
+
+    /**
+     * Get the groups the given user is a member of
+     *
+     * @param   User $user
+     *
+     * @return  array
+     */
+    abstract public function getMemberships(User $user);
+}