Use WebSocket to update likes

lib/helpers/likes_helper.dart

@@ -1,5 +1,5 @@
 import 'package:comunic/enums/likes_type.dart';
-import 'package:comunic/models/api_request.dart';
+import 'package:comunic/helpers/websocket_helper.dart';
 import 'package:meta/meta.dart';
 
 /// Likes helper
@@ -15,21 +15,15 @@ const LikesAPIMap = {
 
 class LikesHelper {
   /// Update liking status of an element
-  Future<bool> setLiking({
+  Future<void> setLiking({
     @required LikesType type,
     @required bool like,
     @required int id,
   }) async {
-    return (await APIRequest(
-          uri: "likes/update",
-          needLogin: true,
-          args: {
-            "type": LikesAPIMap[type],
-            "like": like.toString(),
-            "id": id.toString(),
-          },
-        ).exec())
-            .code ==
-        200;
+    return (await ws("likes/update", {
+      "type": LikesAPIMap[type],
+      "like": like.toString(),
+      "id": id.toString(),
+    }));
   }
 }

lib/helpers/websocket_helper.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:convert';
 
 import 'package:comunic/helpers/events_helper.dart';
@@ -13,6 +14,10 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 class WebSocketHelper {
   static WebSocketChannel _ws;
 
+  static int _counter = 0;
+
+  static final _requests = Map<String, Completer<dynamic>>();
+
   /// Check out whether we are currently connected to WebSocket or not
   static bool isConnected() {
     return _ws != null && _ws.closeCode == null;
@@ -57,11 +62,36 @@ class WebSocketHelper {
       // Notify when the channel is closed
       onDone: () {
         print("WS Channel closed");
+
+        // Clear Futures queue
+        _requests.clear();
+
         EventsHelper.emit(WSClosedEvent());
       },
     );
   }
 
+  /// Send a new message
+  ///
+  /// This method might throw an [Exception] in case of failure
+  static Future<dynamic> sendMessage(String title, dynamic data) {
+    if (!isConnected())
+      throw Exception("WS: Trying to send message but websocket is closed!");
+
+    final completer = Completer();
+
+    final id = "freq-${_counter++}";
+
+    final msg = WsMessage(id: id, title: title, data: data).toJSON();
+
+    print("WS Send message: $msg");
+
+    _ws.sink.add(msg);
+
+    _requests[id] = completer;
+    return completer.future;
+  }
+
   /// Process incoming message
   static _processMessage(String msgStr) {
     try {
@@ -70,7 +100,7 @@ class WebSocketHelper {
       if (!msg.hasId)
         _processUnattendedMessage(msg);
       else
-        throw Exception("Do not know how to process attended message!");
+        _respondRequests(msg);
     } catch (e, stack) {
       print("WS could not process message: $e");
       print(stack);
@@ -94,4 +124,25 @@ class WebSocketHelper {
         throw Exception("Unknown message type: ${msg.title}");
     }
   }
+
+  /// Process responses to requests
+  static _respondRequests(WsMessage msg) {
+    if (!_requests.containsKey(msg.id))
+      throw Exception(
+          "Could not find request ${msg.id} in the requests queue!");
+
+    final completer = _requests.remove(msg.id);
+
+    // Handles errors
+    if (msg.title != "success") {
+      completer.completeError(Exception("Could not process request!"));
+      return;
+    }
+
+    completer.complete(msg.data);
+  }
 }
+
+/// Helper function
+Future<dynamic> ws(String title, dynamic data) =>
+    WebSocketHelper.sendMessage(title, data);

lib/models/ws_message.dart

@@ -1,3 +1,5 @@
+import 'dart:convert';
+
 import 'package:flutter/widgets.dart';
 
 /// WebSocket message
@@ -14,12 +16,21 @@ class WsMessage {
     @required this.title,
     @required this.data,
   })  : assert(id != null),
-        assert(title != null);
+        assert(title != null),
+        assert(title.length > 0);
 
   /// Construct a message from a JSON document (messages coming from the server)
   static WsMessage fromJSON(final Map<dynamic, dynamic> m) {
     return WsMessage(id: m["id"], title: m["title"], data: m["data"]);
   }
 
+  /// Turn a message into a JSON object to send it to the API
+  String toJSON() =>
+      jsonEncode({
+        "id": id,
+        "title": title,
+        "data": data,
+      });
+
   bool get hasId => this.id != null && this.id.isNotEmpty;
 }

lib/ui/widgets/like_widget.dart

@@ -71,13 +71,16 @@ class _LikeWidgetState extends SafeState<LikeWidget> {
   /// Toggle like status
   void _toggleLike() async {
     // As like are not really important, we ignore failures
-    if (await LikesHelper()
-        .setLiking(type: elem.likeType, like: !elem.userLike, id: elem.id)) {
+    try {
+      await LikesHelper()
+          .setLiking(type: elem.likeType, like: !elem.userLike, id: elem.id);
       setState(() {
         elem.userLike = !elem.userLike;
 
         elem.likes += elem.userLike ? 1 : -1;
       });
+    } catch (e, stack) {
+      print("$e\n$stack");
     }
   }
 }