[Client] Implement thumbnails

lib/src/client.dart

@@ -488,6 +488,7 @@ class Client {
 
   /// Uploads a new user avatar for this user.
   Future<void> setAvatar(MatrixFile file) async {
+    await file.resize(width: 128);
     final uploadResp = await upload(file);
     await jsonRequest(
         type: HTTPType.PUT,

lib/src/event.dart

@@ -429,31 +429,50 @@ class Event {
     return;
   }
 
+  bool get hasThumbnail =>
+      content['info'] is Map<String, dynamic> &&
+      (content['info'].containsKey('thumbnail_url') ||
+          content['info'].containsKey('thumbnail_file'));
+
   /// Downloads (and decryptes if necessary) the attachment of this
   /// event and returns it as a [MatrixFile]. If this event doesn't
-  /// contain an attachment, this throws an error.
-  Future<MatrixFile> downloadAndDecryptAttachment() async {
+  /// contain an attachment, this throws an error. Set [getThumbnail] to
+  /// true to download the thumbnail instead.
+  Future<MatrixFile> downloadAndDecryptAttachment(
+      {bool getThumbnail = false}) async {
     if (![EventTypes.Message, EventTypes.Sticker].contains(type)) {
       throw ("This event has the type '$typeKey' and so it can't contain an attachment.");
     }
-    if (!content.containsKey('url') && !content.containsKey('file')) {
+    if (!getThumbnail &&
+        !content.containsKey('url') &&
+        !content.containsKey('file')) {
       throw ("This event hasn't any attachment.");
     }
-    final isEncrypted = !content.containsKey('url');
+    if (getThumbnail && !hasThumbnail) {
+      throw ("This event hasn't any thumbnail.");
+    }
+    final isEncrypted = getThumbnail
+        ? !content['info'].containsKey('thumbnail_url')
+        : !content.containsKey('url');
 
     if (isEncrypted && !room.client.encryptionEnabled) {
       throw ('Encryption is not enabled in your Client.');
     }
-    var mxContent =
-        MxContent(isEncrypted ? content['file']['url'] : content['url']);
+    var mxContent = getThumbnail
+        ? MxContent(isEncrypted
+            ? content['info']['thumbnail_file']['url']
+            : content['info']['thumbnail_url'])
+        : MxContent(isEncrypted ? content['file']['url'] : content['url']);
 
     Uint8List uint8list;
 
     // Is this file storeable?
+    final infoMap =
+        getThumbnail ? content['info']['thumbnail_info'] : content['info'];
     final storeable = room.client.storeAPI.extended &&
-        content['info'] is Map<String, dynamic> &&
-        content['info']['size'] is int &&
-        content['info']['size'] <= ExtendedStoreAPI.MAX_FILE_SIZE;
+        infoMap is Map<String, dynamic> &&
+        infoMap['size'] is int &&
+        infoMap['size'] <= ExtendedStoreAPI.MAX_FILE_SIZE;
 
     if (storeable) {
       uint8list = await room.client.store.getFile(mxContent.mxc);
@@ -470,15 +489,16 @@ class Event {
 
     // Decrypt the file
     if (isEncrypted) {
-      if (!content.containsKey('file') ||
-          !content['file']['key']['key_ops'].contains('decrypt')) {
+      final fileMap =
+          getThumbnail ? content['info']['thumbnail_file'] : content['file'];
+      if (!fileMap['key']['key_ops'].contains('decrypt')) {
         throw ("Missing 'decrypt' in 'key_ops'.");
       }
       final encryptedFile = EncryptedFile();
       encryptedFile.data = uint8list;
-      encryptedFile.iv = content['file']['iv'];
-      encryptedFile.k = content['file']['key']['k'];
-      encryptedFile.sha256 = content['file']['hashes']['sha256'];
+      encryptedFile.iv = fileMap['iv'];
+      encryptedFile.k = fileMap['key']['k'];
+      encryptedFile.sha256 = fileMap['hashes']['sha256'];
       uint8list = await decryptFile(encryptedFile);
     }
     return MatrixFile(bytes: uint8list, path: '/$body');

lib/src/room.dart

@@ -34,6 +34,7 @@ import 'package:famedlysdk/src/utils/matrix_exception.dart';
 import 'package:famedlysdk/src/utils/matrix_file.dart';
 import 'package:famedlysdk/src/utils/mx_content.dart';
 import 'package:famedlysdk/src/utils/session_key.dart';
+import 'package:image/image.dart';
 import 'package:matrix_file_e2ee/matrix_file_e2ee.dart';
 import 'package:mime_type/mime_type.dart';
 import 'package:olm/olm.dart' as olm;
@@ -478,17 +479,13 @@ class Room {
     Map<String, dynamic> info,
     bool waitUntilSent = false,
   }) async {
-    var fileName = file.path.split('/').last;
-    final sendEncrypted = encrypted && client.fileEncryptionEnabled;
-    EncryptedFile encryptedFile;
-    if (sendEncrypted) {
-      encryptedFile = await file.encrypt();
-    }
-    final uploadResp = await client.upload(
-      file,
-      contentType: sendEncrypted ? 'application/octet-stream' : null,
-    );
+    Image fileImage;
+    Image thumbnailImage;
+    MatrixFile thumbnail;
+    EncryptedFile encryptedThumbnail;
+    String thumbnailUploadResp;
 
+    var fileName = file.path.split('/').last;
     final mimeType = mime(file.path) ?? '';
     if (msgType == null) {
       final metaType = (mimeType).split('/')[0];
@@ -504,6 +501,35 @@ class Room {
       }
     }
 
+    if (msgType == 'm.image') {
+      var thumbnailPathParts = file.path.split('/');
+      thumbnailPathParts.last = 'thumbnail_' + thumbnailPathParts.last;
+      final thumbnailPath = thumbnailPathParts.join('/');
+      thumbnail = MatrixFile(bytes: file.bytes, path: thumbnailPath);
+      await thumbnail.resize(width: 512);
+      fileImage = decodeImage(file.bytes.toList());
+      thumbnailImage = decodeImage(thumbnail.bytes.toList());
+    }
+
+    final sendEncrypted = encrypted && client.fileEncryptionEnabled;
+    EncryptedFile encryptedFile;
+    if (sendEncrypted) {
+      encryptedFile = await file.encrypt();
+      if (thumbnail != null) {
+        encryptedThumbnail = await thumbnail.encrypt();
+      }
+    }
+    final uploadResp = await client.upload(
+      file,
+      contentType: sendEncrypted ? 'application/octet-stream' : null,
+    );
+    if (thumbnail != null) {
+      thumbnailUploadResp = await client.upload(
+        thumbnail,
+        contentType: sendEncrypted ? 'application/octet-stream' : null,
+      );
+    }
+
     // Send event
     var content = <String, dynamic>{
       'msgtype': msgType,
@@ -529,6 +555,32 @@ class Room {
           {
             'mimetype': mimeType,
             'size': file.size,
+            if (fileImage != null) 'h': fileImage.height,
+            if (fileImage != null) 'w': fileImage.width,
+            if (thumbnailUploadResp != null && !sendEncrypted)
+              'thumbnail_url': thumbnailUploadResp,
+            if (thumbnailUploadResp != null && sendEncrypted)
+              'thumbnail_file': {
+                'url': thumbnailUploadResp,
+                'mimetype': mimeType,
+                'v': 'v2',
+                'key': {
+                  'alg': 'A256CTR',
+                  'ext': true,
+                  'k': encryptedThumbnail.k,
+                  'key_ops': ['encrypt', 'decrypt'],
+                  'kty': 'oct'
+                },
+                'iv': encryptedThumbnail.iv,
+                'hashes': {'sha256': encryptedThumbnail.sha256}
+              },
+            if (thumbnailImage != null)
+              'thumbnail_info': {
+                'h': thumbnailImage.height,
+                'mimetype': mimeType,
+                'size': thumbnailImage.length,
+                'w': thumbnailImage.width,
+              }
           }
     };
     final sendResponse = sendEvent(
@@ -1198,6 +1250,7 @@ class Room {
   /// Uploads a new user avatar for this room. Returns the event ID of the new
   /// m.room.avatar event.
   Future<String> setAvatar(MatrixFile file) async {
+    await file.resize(width: 256);
     final uploadResp = await client.upload(file);
     final setAvatarResp = await client.jsonRequest(
         type: HTTPType.PUT,

lib/src/utils/matrix_file.dart

@@ -2,12 +2,31 @@
 
 import 'dart:typed_data';
 
+import 'package:image/image.dart';
 import 'package:matrix_file_e2ee/matrix_file_e2ee.dart';
 
 class MatrixFile {
   Uint8List bytes;
   String path;
 
+  /// If this file is an Image, this will resize it to the
+  /// given width and height. Otherwise returns false.
+  /// At least width or height must be set!
+  Future<bool> resize({int width, int height}) async {
+    if (width == null && height == null) {
+      throw ('At least width or height must be set!');
+    }
+    Image image;
+    try {
+      image = decodeImage(bytes);
+    } catch (_) {
+      return false;
+    }
+    final resizedImage = copyResize(image, width: width, height: height);
+    bytes = encodePng(resizedImage);
+    return true;
+  }
+
   /// Encrypts this file, changes the [bytes] and returns the
   /// encryption information as an [EncryptedFile].
   Future<EncryptedFile> encrypt() async {

pubspec.lock

@@ -8,6 +8,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.36.3"
+  archive:
+    dependency: transitive
+    description:
+      name: archive
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.13"
   args:
     dependency: transitive
     description:
@@ -211,6 +218,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.1.3"
+  image:
+    dependency: "direct main"
+    description:
+      name: image
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.12"
   io:
     dependency: transitive
     description:
@@ -334,6 +348,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.9.0"
+  petitparser:
+    dependency: transitive
+    description:
+      name: petitparser
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.2"
   pointycastle:
     dependency: transitive
     description:
@@ -516,6 +537,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.13"
+  xml:
+    dependency: transitive
+    description:
+      name: xml
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.7.0"
   yaml:
     dependency: transitive
     description:

pubspec.yaml

@@ -11,6 +11,7 @@ dependencies:
   http: ^0.12.0+4
   mime_type: ^0.2.4
   canonical_json: ^1.0.0
+  image: ^2.1.4
 
   olm:
     git: