[Media] Copy media subsystem from v2 and roughly structure it for v3

plugins/Media/Controller/AttachmentView.php

@@ -0,0 +1,54 @@
+<?php
+// This file is part of GNU social - https://www.gnu.org/software/social
+//
+// GNU social 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.
+//
+// GNU social 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 GNU social.  If not, see <http://www.gnu.org/licenses/>.
+
+namespace Plugin\Media\Controller;
+
+/**
+ * View notice attachment
+ *
+ * @package  GNUsocial
+ *
+ * @author   Miguel Dantas <biodantasgs@gmail.com>
+ * @license  https://www.gnu.org/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ */
+class AttachmentView extends Attachment
+{
+    public function showPage(): void
+    {
+        // Disable errors, to not mess with the file contents (suppress errors in case access to this
+        // function is blocked, like in some shared hosts). Automatically reset at the end of the
+        // script execution, and we don't want to have any more errors until then, so don't reset it
+        @ini_set('display_errors', 0);
+
+        if ($this->attachment->isLocal() || $this->attachment->isFetchedRemoteFile()) {
+            try {
+                $this->filepath = $this->attachment->getFileOrThumbnailPath();
+            } catch (Exception $e) {
+                $this->clientError(
+                    _m('Requested local URL for a file that is not stored locally.'),
+                    404
+                );
+            }
+            $disposition = 'attachment';
+            if (in_array(common_get_mime_media($this->mimetype), ['image', 'video'])) {
+                $disposition = 'inline';
+            }
+            common_send_file($this->filepath, $this->mimetype, $this->filename, $disposition);
+        } else {
+            common_redirect($this->attachment->getUrl(), 303);
+        }
+    }
+}