Catch most exceptions.

app/Support/Http/Api/ValidatesUserGroupTrait.php

@@ -0,0 +1,65 @@
+<?php
+/*
+ * ValidatesUserGroupTrait.php
+ * Copyright (c) 2023 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace FireflyIII\Support\Http\Api;
+
+use FireflyIII\Exceptions\FireflyException;
+use FireflyIII\Models\GroupMembership;
+use FireflyIII\Models\UserGroup;
+use FireflyIII\User;
+use Illuminate\Http\Request;
+
+trait ValidatesUserGroupTrait
+{
+    /**
+     * This check does not validate which rights the user has, that comes later.
+     *
+     * @param Request $request
+     *
+     * @return UserGroup|null
+     * @throws FireflyException
+     */
+    protected function validateUserGroup(Request $request): ?UserGroup
+    {
+        if (!auth()->check()) {
+            app('log')->debug('validateUserGroup: user is not logged in, return NULL.');
+            return null;
+        }
+        /** @var User $user */
+        $user = auth()->user();
+        if (!$request->has('user_group_id')) {
+            $group = $user->userGroup;
+            app('log')->debug(sprintf('validateUserGroup: no user group submitted, return default group #%d.', $group->id));
+            return $group;
+        }
+        $groupId = (int)$request->get('user_group_id');
+        /** @var GroupMembership|null $membership */
+        $membership = $user->groupMemberships()->where('user_group_id', $groupId)->first();
+        if (null === $membership) {
+            app('log')->debug('validateUserGroup: user has no access to this group.');
+            throw new FireflyException((string)trans('validation.belongs_user_or_user_group'));
+        }
+        app('log')->debug(sprintf('validateUserGroup: user has role "%s" in group #%d.', $membership->userRole->title, $membership->userGroup->id));
+        return $membership->userGroup;
+    }
+}