fix: Retry sending a file event

lib/src/event.dart

@@ -22,6 +22,7 @@ import 'dart:typed_data';
 import 'package:collection/collection.dart';
 import 'package:html/parser.dart';
 import 'package:http/http.dart' as http;
+import 'package:matrix/src/utils/file_send_request_credentials.dart';
 
 import '../matrix.dart';
 import 'utils/event_localizations.dart';
@@ -136,6 +137,18 @@ class Event extends MatrixEvent {
         );
       }
     }
+
+    // If this is failed to send and the file is no longer cached, it should be removed!
+    if (!status.isSent &&
+        {
+          MessageTypes.Image,
+          MessageTypes.Video,
+          MessageTypes.Audio,
+          MessageTypes.File,
+        }.contains(messageType) &&
+        !room.sendingFilePlaceholders.containsKey(eventId)) {
+      remove();
+    }
   }
 
   static Map<String, dynamic> getMapFromPayload(dynamic payload) {
@@ -327,12 +340,34 @@ class Event extends MatrixEvent {
   /// Try to send this event again. Only works with events of status -1.
   Future<String?> sendAgain({String? txid}) async {
     if (!status.isError) return null;
-    // If this is a failed file sending event, try to fetch the file from the
+
-    // database first.
+    // Retry sending a file:
-    final url = getAttachmentUrl();
+    if ({
-    if (url?.scheme == 'local') {
+      MessageTypes.Image,
-      final file = await downloadAndDecryptAttachment();
+      MessageTypes.Video,
-      return await room.sendFileEvent(file, extraContent: content);
+      MessageTypes.Audio,
+      MessageTypes.File,
+    }.contains(messageType)) {
+      final file = room.sendingFilePlaceholders[eventId];
+      if (file == null) {
+        await remove();
+        throw Exception('Can not try to send again. File is no longer cached.');
+      }
+      final thumbnail = room.sendingFileThumbnails[eventId];
+      final credentials = FileSendRequestCredentials.fromJson(unsigned ?? {});
+      final inReplyTo = credentials.inReplyTo == null
+          ? null
+          : await room.getEventById(credentials.inReplyTo!);
+      txid ??= unsigned?.tryGet<String>('transaction_id');
+      return await room.sendFileEvent(
+        file,
+        txid: txid,
+        thumbnail: thumbnail,
+        inReplyTo: inReplyTo,
+        editEventId: credentials.editEventId,
+        shrinkImageMaxDimension: credentials.shrinkImageMaxDimension,
+        extraContent: credentials.extraContent,
+      );
     }
 
     // we do not remove the event here. It will automatically be updated

lib/src/room.dart

@@ -23,6 +23,7 @@ import 'dart:typed_data';
 import 'package:collection/collection.dart';
 import 'package:html_unescape/html_unescape.dart';
 import 'package:matrix/src/utils/crypto/crypto.dart';
+import 'package:matrix/src/utils/file_send_request_credentials.dart';
 import 'package:matrix/src/utils/space_child.dart';
 import 'package:matrix/widget.dart';
 
@@ -683,6 +684,7 @@ class Room {
   }
 
   final Map<String, MatrixFile> sendingFilePlaceholders = {};
+  final Map<String, MatrixImageFile> sendingFileThumbnails = {};
 
   /// Sends a [file] to this room after uploading it. Returns the mxc uri of
   /// the uploaded file. If [waitUntilSent] is true, the future will wait until
@@ -706,6 +708,9 @@ class Room {
   }) async {
     txid ??= client.generateUniqueTransactionId();
     sendingFilePlaceholders[txid] = file;
+    if (thumbnail != null) {
+      sendingFileThumbnails[txid] = thumbnail;
+    }
 
     // Create a fake Event object as a placeholder for the uploading file:
     final syncUpdate = SyncUpdate(
@@ -728,6 +733,12 @@ class Room {
                   unsigned: {
                     messageSendingStatusKey: EventStatus.sending.intValue,
                     'transaction_id': txid,
+                    ...FileSendRequestCredentials(
+                      inReplyTo: inReplyTo?.eventId,
+                      editEventId: editEventId,
+                      shrinkImageMaxDimension: shrinkImageMaxDimension,
+                      extraContent: extraContent,
+                    ).toJson(),
                   },
                 ),
               ],
@@ -805,14 +816,12 @@ class Room {
         syncUpdate.rooms!.join!.values.first.timeline!.events!.first
             .unsigned![messageSendingStatusKey] = EventStatus.error.intValue;
         await _handleFakeSync(syncUpdate);
-        sendingFilePlaceholders.remove(txid);
         rethrow;
       } catch (_) {
         if (DateTime.now().isAfter(timeoutDate)) {
           syncUpdate.rooms!.join!.values.first.timeline!.events!.first
               .unsigned![messageSendingStatusKey] = EventStatus.error.intValue;
           await _handleFakeSync(syncUpdate);
-          sendingFilePlaceholders.remove(txid);
           rethrow;
         }
         Logs().v('Send File into room failed. Try again...');
@@ -875,6 +884,7 @@ class Room {
       editEventId: editEventId,
     );
     sendingFilePlaceholders.remove(txid);
+    sendingFileThumbnails.remove(txid);
     return eventId;
   }
 

lib/src/utils/file_send_request_credentials.dart

@@ -0,0 +1,47 @@
+/*
+ *   Famedly Matrix SDK
+ *   Copyright (C) 2019, 2020, 2021 Famedly GmbH
+ *
+ *   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/>.
+ */
+
+class FileSendRequestCredentials {
+  final String? inReplyTo;
+  final String? editEventId;
+  final int? shrinkImageMaxDimension;
+  final Map<String, dynamic>? extraContent;
+
+  const FileSendRequestCredentials({
+    this.inReplyTo,
+    this.editEventId,
+    this.shrinkImageMaxDimension,
+    this.extraContent,
+  });
+
+  factory FileSendRequestCredentials.fromJson(Map<String, dynamic> json) =>
+      FileSendRequestCredentials(
+        inReplyTo: json['in_reply_to'],
+        editEventId: json['edit_event_id'],
+        shrinkImageMaxDimension: json['shrink_image_max_dimension'],
+        extraContent: json['extra_content'],
+      );
+
+  Map<String, dynamic> toJson() => {
+        if (inReplyTo != null) 'in_reply_to': inReplyTo,
+        if (editEventId != null) 'edit_event_id': editEventId,
+        if (shrinkImageMaxDimension != null)
+          'shrink_image_max_dimension': shrinkImageMaxDimension,
+        if (extraContent != null) 'extra_content': extraContent,
+      };
+}