Improve Twitch PubSub connection reliability (#3643)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/providers/twitch/pubsubmessages/Message.hpp

@@ -0,0 +1,60 @@
+#pragma once
+
+#include "common/QLogging.hpp"
+
+#include <QJsonDocument>
+#include <QJsonObject>
+#include <QString>
+
+#include <boost/optional.hpp>
+
+namespace chatterino {
+
+struct PubSubMessageMessage {
+    QString nonce;
+    QString topic;
+
+    QJsonObject messageObject;
+
+    PubSubMessageMessage(QString _nonce, const QJsonObject &data)
+        : nonce(std::move(_nonce))
+        , topic(data.value("topic").toString())
+    {
+        auto messagePayload = data.value("message").toString().toUtf8();
+
+        auto messageDoc = QJsonDocument::fromJson(messagePayload);
+
+        if (messageDoc.isNull())
+        {
+            qCWarning(chatterinoPubSub) << "PubSub message (type MESSAGE) "
+                                           "missing inner message payload";
+            return;
+        }
+
+        if (!messageDoc.isObject())
+        {
+            qCWarning(chatterinoPubSub)
+                << "PubSub message (type MESSAGE) inner message payload is not "
+                   "an object";
+            return;
+        }
+
+        this->messageObject = messageDoc.object();
+    }
+
+    template <class InnerClass>
+    boost::optional<InnerClass> toInner() const;
+};
+
+template <class InnerClass>
+boost::optional<InnerClass> PubSubMessageMessage::toInner() const
+{
+    if (this->messageObject.empty())
+    {
+        return boost::none;
+    }
+
+    return InnerClass{this->messageObject};
+}
+
+}  // namespace chatterino