feat: Implement XEP-0449

packages/moxxmpp/lib/moxxmpp.dart

@@ -79,4 +79,5 @@ export 'package:moxxmpp/src/xeps/xep_0444.dart';
 export 'package:moxxmpp/src/xeps/xep_0446.dart';
 export 'package:moxxmpp/src/xeps/xep_0447.dart';
 export 'package:moxxmpp/src/xeps/xep_0448.dart';
+export 'package:moxxmpp/src/xeps/xep_0449.dart';
 export 'package:moxxmpp/src/xeps/xep_0461.dart';

packages/moxxmpp/lib/src/events.dart

@@ -79,6 +79,7 @@ class MessageEvent extends XmppEvent {
     this.messageCorrectionId,
     this.messageReactions,
     this.messageProcessingHints,
+    this.stickerPackId,
   });
   final StanzaError? error;
   final String body;
@@ -103,6 +104,7 @@ class MessageEvent extends XmppEvent {
   final String? messageCorrectionId;
   final MessageReactions? messageReactions;
   final List<MessageProcessingHint>? messageProcessingHints;
+  final String? stickerPackId;
   final Map<String, dynamic> other;
 }
 

packages/moxxmpp/lib/src/managers/data.dart

@@ -64,6 +64,8 @@ class StanzaHandlerData with _$StanzaHandlerData {
       String? lastMessageCorrectionSid,
       // Reactions data
       MessageReactions? messageReactions,
+      // The Id of the sticker pack this sticker belongs to
+      String? stickerPackId,
     }
   ) = _StanzaHandlerData;
 }

packages/moxxmpp/lib/src/managers/data.freezed.dart

@@ -61,7 +61,9 @@ mixin _$StanzaHandlerData {
       throw _privateConstructorUsedError; // If non-null, then the message is a correction for the specified stanza Id
   String? get lastMessageCorrectionSid =>
       throw _privateConstructorUsedError; // Reactions data
-  MessageReactions? get messageReactions => throw _privateConstructorUsedError;
+  MessageReactions? get messageReactions =>
+      throw _privateConstructorUsedError; // The Id of the sticker pack this sticker belongs to
+  String? get stickerPackId => throw _privateConstructorUsedError;
 
   @JsonKey(ignore: true)
   $StanzaHandlerDataCopyWith<StanzaHandlerData> get copyWith =>
@@ -97,7 +99,8 @@ abstract class $StanzaHandlerDataCopyWith<$Res> {
       Map<String, dynamic> other,
       MessageRetractionData? messageRetraction,
       String? lastMessageCorrectionSid,
-      MessageReactions? messageReactions});
+      MessageReactions? messageReactions,
+      String? stickerPackId});
 }
 
 /// @nodoc
@@ -135,6 +138,7 @@ class _$StanzaHandlerDataCopyWithImpl<$Res>
     Object? messageRetraction = freezed,
     Object? lastMessageCorrectionSid = freezed,
     Object? messageReactions = freezed,
+    Object? stickerPackId = freezed,
   }) {
     return _then(_value.copyWith(
       done: done == freezed
@@ -233,6 +237,10 @@ class _$StanzaHandlerDataCopyWithImpl<$Res>
           ? _value.messageReactions
           : messageReactions // ignore: cast_nullable_to_non_nullable
               as MessageReactions?,
+      stickerPackId: stickerPackId == freezed
+          ? _value.stickerPackId
+          : stickerPackId // ignore: cast_nullable_to_non_nullable
+              as String?,
     ));
   }
 }
@@ -268,7 +276,8 @@ abstract class _$$_StanzaHandlerDataCopyWith<$Res>
       Map<String, dynamic> other,
       MessageRetractionData? messageRetraction,
       String? lastMessageCorrectionSid,
-      MessageReactions? messageReactions});
+      MessageReactions? messageReactions,
+      String? stickerPackId});
 }
 
 /// @nodoc
@@ -308,6 +317,7 @@ class __$$_StanzaHandlerDataCopyWithImpl<$Res>
     Object? messageRetraction = freezed,
     Object? lastMessageCorrectionSid = freezed,
     Object? messageReactions = freezed,
+    Object? stickerPackId = freezed,
   }) {
     return _then(_$_StanzaHandlerData(
       done == freezed
@@ -406,6 +416,10 @@ class __$$_StanzaHandlerDataCopyWithImpl<$Res>
           ? _value.messageReactions
           : messageReactions // ignore: cast_nullable_to_non_nullable
               as MessageReactions?,
+      stickerPackId: stickerPackId == freezed
+          ? _value.stickerPackId
+          : stickerPackId // ignore: cast_nullable_to_non_nullable
+              as String?,
     ));
   }
 }
@@ -433,7 +447,8 @@ class _$_StanzaHandlerData implements _StanzaHandlerData {
       final Map<String, dynamic> other = const <String, dynamic>{},
       this.messageRetraction,
       this.lastMessageCorrectionSid,
-      this.messageReactions})
+      this.messageReactions,
+      this.stickerPackId})
       : _other = other;
 
 // Indicates to the runner that processing is now done. This means that all
@@ -519,10 +534,13 @@ class _$_StanzaHandlerData implements _StanzaHandlerData {
 // Reactions data
   @override
   final MessageReactions? messageReactions;
+// The Id of the sticker pack this sticker belongs to
+  @override
+  final String? stickerPackId;
 
   @override
   String toString() {
-    return 'StanzaHandlerData(done: $done, cancel: $cancel, cancelReason: $cancelReason, stanza: $stanza, retransmitted: $retransmitted, sims: $sims, sfs: $sfs, oob: $oob, stableId: $stableId, reply: $reply, chatState: $chatState, isCarbon: $isCarbon, deliveryReceiptRequested: $deliveryReceiptRequested, isMarkable: $isMarkable, fun: $fun, funReplacement: $funReplacement, funCancellation: $funCancellation, encrypted: $encrypted, encryptionType: $encryptionType, delayedDelivery: $delayedDelivery, other: $other, messageRetraction: $messageRetraction, lastMessageCorrectionSid: $lastMessageCorrectionSid, messageReactions: $messageReactions)';
+    return 'StanzaHandlerData(done: $done, cancel: $cancel, cancelReason: $cancelReason, stanza: $stanza, retransmitted: $retransmitted, sims: $sims, sfs: $sfs, oob: $oob, stableId: $stableId, reply: $reply, chatState: $chatState, isCarbon: $isCarbon, deliveryReceiptRequested: $deliveryReceiptRequested, isMarkable: $isMarkable, fun: $fun, funReplacement: $funReplacement, funCancellation: $funCancellation, encrypted: $encrypted, encryptionType: $encryptionType, delayedDelivery: $delayedDelivery, other: $other, messageRetraction: $messageRetraction, lastMessageCorrectionSid: $lastMessageCorrectionSid, messageReactions: $messageReactions, stickerPackId: $stickerPackId)';
   }
 
   @override
@@ -564,7 +582,9 @@ class _$_StanzaHandlerData implements _StanzaHandlerData {
             const DeepCollectionEquality().equals(
                 other.lastMessageCorrectionSid, lastMessageCorrectionSid) &&
             const DeepCollectionEquality()
-                .equals(other.messageReactions, messageReactions));
+                .equals(other.messageReactions, messageReactions) &&
+            const DeepCollectionEquality()
+                .equals(other.stickerPackId, stickerPackId));
   }
 
   @override
@@ -593,7 +613,8 @@ class _$_StanzaHandlerData implements _StanzaHandlerData {
         const DeepCollectionEquality().hash(_other),
         const DeepCollectionEquality().hash(messageRetraction),
         const DeepCollectionEquality().hash(lastMessageCorrectionSid),
-        const DeepCollectionEquality().hash(messageReactions)
+        const DeepCollectionEquality().hash(messageReactions),
+        const DeepCollectionEquality().hash(stickerPackId)
       ]);
 
   @JsonKey(ignore: true)
@@ -625,7 +646,8 @@ abstract class _StanzaHandlerData implements StanzaHandlerData {
       final Map<String, dynamic> other,
       final MessageRetractionData? messageRetraction,
       final String? lastMessageCorrectionSid,
-      final MessageReactions? messageReactions}) = _$_StanzaHandlerData;
+      final MessageReactions? messageReactions,
+      final String? stickerPackId}) = _$_StanzaHandlerData;
 
   @override // Indicates to the runner that processing is now done. This means that all
 // pre-processing is done and no other handlers should be consulted.
@@ -682,6 +704,8 @@ abstract class _StanzaHandlerData implements StanzaHandlerData {
   String? get lastMessageCorrectionSid;
   @override // Reactions data
   MessageReactions? get messageReactions;
+  @override // The Id of the sticker pack this sticker belongs to
+  String? get stickerPackId;
   @override
   @JsonKey(ignore: true)
   _$$_StanzaHandlerDataCopyWith<_$_StanzaHandlerData> get copyWith =>

packages/moxxmpp/lib/src/managers/namespaces.dart

@@ -27,3 +27,4 @@ const delayedDeliveryManager = 'org.moxxmpp.delayeddeliverymanager';
 const messageRetractionManager = 'org.moxxmpp.messageretractionmanager';
 const lastMessageCorrectionManager = 'org.moxxmpp.lastmessagecorrectionmanager';
 const messageReactionsManager = 'org.moxxmpp.messagereactionsmanager';
+const stickersManager = 'org.moxxmpp.stickersmanager';

packages/moxxmpp/lib/src/message.dart

@@ -21,6 +21,11 @@ import 'package:moxxmpp/src/xeps/xep_0446.dart';
 import 'package:moxxmpp/src/xeps/xep_0447.dart';
 import 'package:moxxmpp/src/xeps/xep_0448.dart';
 
+/// Data used to build a message stanza.
+///
+/// [setOOBFallbackBody] indicates, when using SFS, whether a OOB fallback should be
+/// added. This is recommended when sharing files but may cause issues when the message
+/// stanza should include a SFS element without any fallbacks.
 class MessageDetails {
   const MessageDetails({
     required this.to,
@@ -42,6 +47,8 @@ class MessageDetails {
     this.lastMessageCorrectionId,
     this.messageReactions,
     this.messageProcessingHints,
+    this.stickerPackId,
+    this.setOOBFallbackBody = true,
   });
   final String to;
   final String? body;
@@ -61,7 +68,9 @@ class MessageDetails {
   final MessageRetractionData? messageRetraction;
   final String? lastMessageCorrectionId;
   final MessageReactions? messageReactions;
+  final String? stickerPackId;
   final List<MessageProcessingHint>? messageProcessingHints;
+  final bool setOOBFallbackBody;
 }
 
 class MessageManager extends XmppManagerBase {
@@ -117,6 +126,7 @@ class MessageManager extends XmppManagerBase {
       messageProcessingHints: hints.isEmpty ?
         null :
         hints,
+      stickerPackId: state.stickerPackId,
       other: state.other,
       error: StanzaError.fromStanza(message),
     ),);
@@ -174,7 +184,7 @@ class MessageManager extends XmppManagerBase {
         );
     } else {
       var body = details.body;
-      if (details.sfs != null) {
+      if (details.sfs != null && details.setOOBFallbackBody) {
         // TODO(Unknown): Maybe find a better solution
         final firstSource = details.sfs!.sources.first;
         if (firstSource is StatelessFileSharingUrlSource) {
@@ -207,7 +217,7 @@ class MessageManager extends XmppManagerBase {
       stanza.addChild(details.sfs!.toXML());
 
       final source = details.sfs!.sources.first;
-      if (source is StatelessFileSharingUrlSource) {
+      if (source is StatelessFileSharingUrlSource && details.setOOBFallbackBody) {
         // SFS recommends OOB as a fallback
         stanza.addChild(constructOOBNode(OOBData(url: source.url)));
       }
@@ -289,6 +299,18 @@ class MessageManager extends XmppManagerBase {
       }
     }
 
+    if (details.stickerPackId != null) {
+      stanza.addChild(
+        XMLNode.xmlns(
+          tag: 'sticker',
+          xmlns: stickersXmlns,
+          attributes: {
+            'pack': details.stickerPackId!,
+          },
+        ),
+      );
+    }
+    
     getAttributes().sendStanza(stanza, awaitable: false);
   }
 }

packages/moxxmpp/lib/src/namespaces.dart

@@ -141,6 +141,9 @@ const sfsEncryptionAes128GcmNoPaddingXmlns = 'urn:xmpp:ciphers:aes-128-gcm-nopad
 const sfsEncryptionAes256GcmNoPaddingXmlns = 'urn:xmpp:ciphers:aes-256-gcm-nopadding:0';
 const sfsEncryptionAes256CbcPkcs7Xmlns = 'urn:xmpp:ciphers:aes-256-cbc-pkcs7:0';
 
+// XEP-0449
+const stickersXmlns = 'urn:xmpp:stickers:0';
+
 // XEP-0461
 const replyXmlns = 'urn:xmpp:reply:0';
 const fallbackXmlns = 'urn:xmpp:feature-fallback:0';

packages/moxxmpp/lib/src/rfcs/rfc_4790.dart

@@ -24,3 +24,28 @@ int ioctetSortComparator(String a, String b) {
   
   return 1;
 }
+
+int ioctetSortComparatorRaw(List<int> a, List<int> b) {
+  if (a.isEmpty && b.isEmpty) {
+    return 0;
+  }
+
+  if (a.isEmpty && b.isNotEmpty) {
+    return -1;
+  }
+
+  if (a.isNotEmpty && b.isEmpty) {
+    return 1;
+  }
+
+  if (a[0] == b[0]) {
+    return ioctetSortComparatorRaw(a.sublist(1), b.sublist(1));
+  }
+
+  // TODO(Unknown): Is this correct?
+  if (a[0] < b[0]) {
+    return -1;
+  }
+  
+  return 1;
+}

packages/moxxmpp/lib/src/xeps/xep_0060/xep_0060.dart

@@ -16,7 +16,6 @@ import 'package:moxxmpp/src/xeps/xep_0060/errors.dart';
 import 'package:moxxmpp/src/xeps/xep_0060/helpers.dart';
 
 class PubSubPublishOptions {
-
   const PubSubPublishOptions({
     this.accessModel,
     this.maxItems,
@@ -60,7 +59,6 @@ class PubSubPublishOptions {
 }
 
 class PubSubItem {
-
   const PubSubItem({ required this.id, required this.node, required this.payload });
   final String id;
   final String node;

packages/moxxmpp/lib/src/xeps/xep_0203.dart

@@ -8,14 +8,12 @@ import 'package:moxxmpp/src/stanza.dart';
 
 @immutable
 class DelayedDelivery {
-
   const DelayedDelivery(this.from, this.timestamp);
   final DateTime timestamp;
   final String from;
 }
 
 class DelayedDeliveryManager extends XmppManagerBase {
-
   @override
   String getId() => delayedDeliveryManager;
 

packages/moxxmpp/lib/src/xeps/xep_0446.dart

@@ -4,7 +4,6 @@ import 'package:moxxmpp/src/xeps/staging/extensible_file_thumbnails.dart';
 import 'package:moxxmpp/src/xeps/xep_0300.dart';
 
 class FileMetadataData {
-
   const FileMetadataData({
     this.mediaType,
     this.width,

packages/moxxmpp/lib/src/xeps/xep_0447.dart

@@ -18,7 +18,6 @@ abstract class StatelessFileSharingSource {
 
 /// Implementation for url-data source elements.
 class StatelessFileSharingUrlSource extends StatelessFileSharingSource {
-
   StatelessFileSharingUrlSource(this.url);
 
   factory StatelessFileSharingUrlSource.fromXml(XMLNode element) {
@@ -41,8 +40,29 @@ class StatelessFileSharingUrlSource extends StatelessFileSharingSource {
   }
 }
 
-class StatelessFileSharingData {
+/// Finds the <sources/> element in [node] and returns the list of
+/// StatelessFileSharingSources contained with it.
+/// If [checkXmlns] is true, then the sources element must also have an xmlns attribute
+/// of "urn:xmpp:sfs:0".
+List<StatelessFileSharingSource> processStatelessFileSharingSources(XMLNode node, { bool checkXmlns = true }) {
+  final sources = List<StatelessFileSharingSource>.empty(growable: true);
   
+  final sourcesElement = node.firstTag(
+    'sources',
+    xmlns: checkXmlns ? sfsXmlns : null,
+  )!;
+  for (final source in sourcesElement.children) {
+    if (source.attributes['xmlns'] == urlDataXmlns) {
+      sources.add(StatelessFileSharingUrlSource.fromXml(source));
+    } else if (source.attributes['xmlns'] == sfsEncryptionXmlns) {
+      sources.add(StatelessFileSharingEncryptedSource.fromXml(source));
+    }
+  }
+
+  return sources;
+}
+
+class StatelessFileSharingData {
   const StatelessFileSharingData(this.metadata, this.sources);
 
   /// Parse [node] as a StatelessFileSharingData element.
@@ -50,20 +70,10 @@ class StatelessFileSharingData {
     assert(node.attributes['xmlns'] == sfsXmlns, 'Invalid element xmlns');
     assert(node.tag == 'file-sharing', 'Invalid element name');
 
-    final sources = List<StatelessFileSharingSource>.empty(growable: true);
-    
-    final sourcesElement = node.firstTag('sources')!;
-    for (final source in sourcesElement.children) {
-      if (source.attributes['xmlns'] == urlDataXmlns) {
-        sources.add(StatelessFileSharingUrlSource.fromXml(source));
-      } else if (source.attributes['xmlns'] == sfsEncryptionXmlns) {
-        sources.add(StatelessFileSharingEncryptedSource.fromXml(source));
-      }
-    }
-
     return StatelessFileSharingData(
       FileMetadataData.fromXML(node.firstTag('file')!),
-      sources,
+      // TODO(PapaTutuWawa): This is a work around for Stickers where the source element has a XMLNS but SFS does not have one.
+      processStatelessFileSharingSources(node, checkXmlns: false),
     );
   }
 
@@ -120,7 +130,7 @@ class SFSManager extends XmppManagerBase {
     final sfs = message.firstTag('file-sharing', xmlns: sfsXmlns)!;
 
     return state.copyWith(
-      sfs: StatelessFileSharingData.fromXML(sfs),
+      sfs: StatelessFileSharingData.fromXML(sfs, ),
     );
   }
 }

packages/moxxmpp/lib/src/xeps/xep_0449.dart

@@ -0,0 +1,308 @@
+import 'dart:convert';
+import 'package:moxxmpp/src/jid.dart';
+import 'package:moxxmpp/src/managers/base.dart';
+import 'package:moxxmpp/src/managers/data.dart';
+import 'package:moxxmpp/src/managers/handlers.dart';
+import 'package:moxxmpp/src/managers/namespaces.dart';
+import 'package:moxxmpp/src/namespaces.dart';
+import 'package:moxxmpp/src/rfcs/rfc_4790.dart';
+import 'package:moxxmpp/src/stanza.dart';
+import 'package:moxxmpp/src/stringxml.dart';
+import 'package:moxxmpp/src/types/result.dart';
+import 'package:moxxmpp/src/xeps/xep_0060/errors.dart';
+import 'package:moxxmpp/src/xeps/xep_0060/xep_0060.dart';
+import 'package:moxxmpp/src/xeps/xep_0300.dart';
+import 'package:moxxmpp/src/xeps/xep_0446.dart';
+import 'package:moxxmpp/src/xeps/xep_0447.dart';
+
+class Sticker {
+  const Sticker(this.metadata, this.sources, this.suggests);
+
+  factory Sticker.fromXML(XMLNode node) {
+    assert(node.tag == 'item', 'sticker has wrong tag');
+
+    return Sticker(
+      FileMetadataData.fromXML(node.firstTag('file', xmlns: fileMetadataXmlns)!),
+      processStatelessFileSharingSources(node, checkXmlns: false),
+      {},
+    );
+  }
+
+  final FileMetadataData metadata;
+  final List<StatelessFileSharingSource> sources;
+  // Language -> suggestion
+  final Map<String, String> suggests; 
+
+  XMLNode toPubSubXML() {
+    final suggestsElements = suggests.keys.map((suggest) {
+      Map<String, String> attrs;
+      if (suggest.isEmpty) {
+        attrs = {};
+      } else {
+        attrs = {
+          'xml:lang': suggest,
+        };
+      }
+
+      return XMLNode(
+        tag: 'suggest',
+        attributes: attrs,
+        text: suggests[suggest],
+      );
+    });
+
+    return XMLNode(
+      tag: 'item',
+      children: [
+        metadata.toXML(),
+        ...sources.map((source) => source.toXml()),
+        ...suggestsElements,
+      ],
+    );
+  }
+}
+
+class StickerPack {
+  const StickerPack(
+    this.id,
+    this.name,
+    this.summary,
+    this.hashAlgorithm,
+    this.hashValue,
+    this.stickers,
+    this.restricted,
+  );
+
+  factory StickerPack.fromXML(String id, XMLNode node, { bool hashAvailable = true }) {
+    assert(node.tag == 'pack', 'node has wrong tag');
+    assert(node.attributes['xmlns'] == stickersXmlns, 'node has wrong XMLNS');
+
+    var hashAlgorithm = HashFunction.sha256;
+    var hashValue = '';
+    if (hashAvailable) {
+      final hash = node.firstTag('hash', xmlns: hashXmlns)!;
+      hashAlgorithm = hashFunctionFromName(hash.attributes['algo']! as String);
+      hashValue = hash.innerText();
+    }
+    
+    return StickerPack(
+      id,
+      node.firstTag('name')!.innerText(),
+      node.firstTag('summary')!.innerText(),
+      hashAlgorithm,
+      hashValue,
+      node.children
+        .where((e) => e.tag == 'item')
+        .map<Sticker>(Sticker.fromXML)
+        .toList(),
+      node.firstTag('restricted') != null,
+    );
+  }
+
+  final String id;
+  // TODO(PapaTutuWawa): Turn name and summary into a Map as it may contain a xml:lang
+  final String name;
+  final String summary;
+  final HashFunction hashAlgorithm;
+  final String hashValue;
+  final List<Sticker> stickers;
+  final bool restricted;
+
+  /// When using the fromXML factory to parse a description of a sticker pack with a
+  /// yet unknown hash, then this function can be used in order to apply the freshly
+  /// calculated hash to the object.
+  StickerPack copyWithId(HashFunction newHashFunction, String newId) {
+    return StickerPack(
+      newId,
+      name,
+      summary,
+      newHashFunction,
+      newId,
+      stickers,
+      restricted,
+    );
+  }
+  
+  XMLNode toXML() {
+    return XMLNode.xmlns(
+      tag: 'pack',
+      xmlns: stickersXmlns,
+      children: [
+        // Pack metadata
+        XMLNode(
+          tag: 'name',
+          text: name,
+        ),
+        XMLNode(
+          tag: 'summary',
+          text: summary,
+        ),
+        constructHashElement(
+          hashAlgorithm.toName(),
+          hashValue,
+        ),
+
+        ...restricted ?
+          [XMLNode(tag: 'restricted')] :
+          [],
+        
+        // Stickers
+        ...stickers
+          .map((sticker) => sticker.toPubSubXML()),
+      ],
+    );
+  }
+
+  /// Calculates the sticker pack's hash as specified by XEP-0449.
+  Future<String> getHash(HashFunction hashFunction) async {
+    // Build the meta string
+    final metaTmp = [
+      <int>[
+        ...utf8.encode('name'),
+        0x1f,
+        0x1f,
+        ...utf8.encode(name),
+        0x1f,
+        0x1e,
+      ],
+      <int>[
+        ...utf8.encode('summary'),
+        0x1f,
+        0x1f,
+        ...utf8.encode(summary),
+        0x1f,
+        0x1e,
+      ],
+    ]..sort(ioctetSortComparatorRaw);
+    final metaString = List<int>.empty(growable: true);
+    for (final m in metaTmp) {
+      metaString.addAll(m);
+    }
+    metaString.add(0x1c);
+
+    // Build item hashes
+    final items = List<List<int>>.empty(growable: true);
+    for (final sticker in stickers) {
+      final tmp = List<int>.empty(growable: true)
+        ..addAll(utf8.encode(sticker.metadata.desc!))
+        ..add(0x1e);
+
+      final hashes = List<List<int>>.empty(growable: true);
+      for (final hash in sticker.metadata.hashes.keys) {
+        hashes.add([
+          ...utf8.encode(hash),
+          0x1f,
+          ...utf8.encode(sticker.metadata.hashes[hash]!),
+          0x1f,
+          0x1e,
+        ]);
+      }
+      hashes.sort(ioctetSortComparatorRaw);
+
+      for (final hash in hashes) {
+        tmp.addAll(hash);
+      }
+      tmp.add(0x1d);
+      items.add(tmp);
+    }
+    items.sort(ioctetSortComparatorRaw);
+    final stickersString = List<int>.empty(growable: true);
+    for (final item in items) {
+      stickersString.addAll(item);
+    }
+    stickersString.add(0x1c);
+
+    // Calculate the hash
+    final rawHash = await CryptographicHashManager.hashFromData(
+      [
+        ...metaString,
+        ...stickersString,
+      ],
+      hashFunction,
+    );
+    return base64.encode(rawHash).substring(0, 24);
+  }
+}
+
+class StickersManager extends XmppManagerBase {
+  @override
+  String getId() => stickersManager;
+
+  @override
+  String getName() => 'StickersManager';
+
+  @override
+  Future<bool> isSupported() async => true;
+
+  @override
+  List<StanzaHandler> getIncomingStanzaHandlers() => [
+    StanzaHandler(
+      stanzaTag: 'message',
+      tagXmlns: stickersXmlns,
+      tagName: 'sticker',
+      callback: _onIncomingMessage,
+      priority: -99,
+    ),
+  ];
+
+  Future<StanzaHandlerData> _onIncomingMessage(Stanza stanza, StanzaHandlerData state) async {
+    final sticker = stanza.firstTag('sticker', xmlns: stickersXmlns)!;
+    return state.copyWith(
+      stickerPackId: sticker.attributes['pack']! as String,
+    );
+  }
+
+  /// Publishes the StickerPack [pack] to the PubSub node of [jid].
+  ///
+  /// On success, returns true. On failure, returns a PubSubError.
+  Future<Result<PubSubError, bool>> publishStickerPack(JID jid, StickerPack pack) async {
+    assert(pack.id != '', 'The sticker pack must have an id');
+    final pm = getAttributes().getManagerById<PubSubManager>(pubsubManager)!;
+
+    return pm.publish(
+      jid.toBare().toString(),
+      stickersXmlns,
+      pack.toXML(),
+      id: pack.id,
+      options: const PubSubPublishOptions(
+        maxItems: 'max',
+      ),
+    );
+  }
+
+  /// Removes the sticker pack with id [id] from the PubSub node of [jid].
+  ///
+  /// On success, returns the true. On failure, returns a PubSubError.
+  Future<Result<PubSubError, bool>> retractStickerPack(JID jid, String id) async {
+    final pm = getAttributes().getManagerById<PubSubManager>(pubsubManager)!;
+
+    return pm.retract(
+      jid,
+      stickersXmlns,
+      id,
+    );
+  }
+
+  /// Fetches the sticker pack with id [id] from [jid].
+  ///
+  /// On success, returns the StickerPack. On failure, returns a PubSubError.
+  Future<Result<PubSubError, StickerPack>> fetchStickerPack(JID jid, String id) async {
+    final pm = getAttributes().getManagerById<PubSubManager>(pubsubManager)!;
+    final stickerPackDataRaw = await pm.getItem(
+      jid.toBare().toString(),
+      stickersXmlns,
+      id,
+    );
+    if (stickerPackDataRaw.isType<PubSubError>()) {
+      return Result(stickerPackDataRaw.get<PubSubError>());
+    }
+
+    final stickerPackData = stickerPackDataRaw.get<PubSubItem>();
+    final stickerPack = StickerPack.fromXML(
+      stickerPackData.id,
+      stickerPackData.payload,
+    );
+
+    return Result(stickerPack);
+  }
+}