[Core] Add LorisInstance class (aces#6118)

This adds a class to LORIS to represent an installed LORIS instance.

It is primarily a stub that can be expanded in the future.

Resolves aces#6022

modules/dashboard/php/dashboard.class.inc

@@ -66,6 +66,8 @@ class Dashboard extends \NDB_Form
         $DB   = \NDB_Factory::singleton()->database();
         $user = \User::singleton();
 
+        // FIXME: This should use \LORIS\LorisInstance->getActiveModules(), but there
+        // is no access to a LORISInstance object at this point in the code.
         $this->modules = \Module::getActiveModules($DB);
 
         $this->smallwidgets = [];

src/LorisInstance.php

@@ -0,0 +1,107 @@
+<?php declare(strict_types=1);
+
+namespace LORIS;
+
+/**
+ * A LorisInstance represents an installed instance of a LORIS
+ * project.
+ *
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ */
+class LorisInstance
+{
+    protected $modulesDirs;
+    private $DB;
+
+    /**
+     * Construct a LORISInstance for the install connected to $db
+     * which uses modules from $moduleDirs.
+     *
+     * @param \Database $db         A database connection to this
+     *                              instance.
+     * @param string[]  $moduleDirs A list of directories that may
+     *                              contain modules for this instance.
+     */
+    public function __construct(\Database $db, array $modulesDirs)
+    {
+        $this->DB          = $db;
+        $this->modulesDirs = $modulesDirs;
+    }
+
+    /**
+     * Return an active database connection to this instance.
+     *
+     * @return \Database
+     */
+    public function getDatabaseConnection() : \Database
+    {
+        return $this->DB;
+    }
+
+    /**
+     * Return a list of directories on the filesystem which
+     * may contain modules.
+     *
+     * @return string[]
+     */
+    private function getModulesDirs() : array
+    {
+        return $this->modulesDirs;
+    }
+
+    /**
+     * Retrieve all active module descriptors from the given database.
+     *
+     * @param \Database $db an open connection to a database containing a 'modules'
+     *                      table
+     *
+     * @return \Module[]
+     */
+    public function getActiveModules(): array
+    {
+        $mnames = $this->getDatabaseConnection()->pselectCol(
+            "SELECT Name FROM modules WHERE Active='Y'",
+            []
+        );
+
+        $modules = [];
+        foreach ($mnames as $name) {
+            try {
+                $modules[] = \Module::factory($name);
+            } catch (\LorisModuleMissingException $e) {
+                error_log($e->getMessage() . " " . $e->getTraceAsString());
+            }
+        }
+        return $modules;
+    }
+
+    /**
+     * Return true if the LORISInstance has a module named
+     * $name. To be installed it must be both available on
+     * the filesystem and active in the modules table.
+     *
+     * @return bool
+     */
+    public function hasModule(string $name) : bool
+    {
+        $dirs  = $this->getModulesDirs();
+        $found = false;
+        foreach ($dirs as $subdir) {
+            if (is_dir($subdir . "/" . $name)) {
+                $found = true;
+                break;
+            }
+        }
+
+        if ($found === false) {
+            return false;
+        }
+
+        foreach ($this->getActiveModules() as $module) {
+            if ($module->getName() == $name) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

src/Middleware/UserPageDecorationMiddleware.php

@@ -22,8 +22,7 @@ public function __construct(
         string $pagename,
         \NDB_Config $config,
         array $JS,
-        array $CSS,
-        \Database $DB
+        array $CSS
     ) {
 
         $this->JSFiles  = $JS;
@@ -32,7 +31,6 @@ public function __construct(
         $this->BaseURL  = $baseurl;
         $this->PageName = $pagename;
         $this->user     = $user;
-        $this->DB       = $DB;
     }
 
     /**
@@ -48,14 +46,15 @@ public function process(ServerRequestInterface $request, RequestHandlerInterface
     {
         ob_start();
         // Set the page template variables
-        // $user is set by the page base router
+        // $user and $loris is set by the page base router
         $user     = $request->getAttribute("user");
+        $loris    = $request->getAttribute("loris");
         $tpl_data = array(
                      'test_name' => $this->PageName,
                     );
+        $menu     = [];
 
-        $menu    = [];
-        $modules = \Module::getActiveModules($this->DB);
+        $modules = $loris->getActiveModules();
         foreach ($modules as $module) {
             if (!$module->hasAccess($user)) {
                 continue;