Downoad all images in the background and keep them in memory

As one of the first steps to offline capability we download all
images and put them into the JSON stirng and into the content
as data-uris for <img>-tags. This way you can go offline and keep
enjoying pictures in your feeds, at least untill you restart
FeedTheMonkey for now.

src/post.cpp

@@ -28,6 +28,33 @@ Post::Post(QObject *parent) : QObject(parent)
 }
 
 Post::Post(QJsonObject post, QObject *parent) : QObject(parent)
+{
+    populateFromJson(post);
+}
+
+Post::Post(QJsonObject post, QNetworkAccessManager *networkManager, QObject *parent) : QObject(parent)
+{
+    mNetworkManager = networkManager;
+    populateFromJson(post);
+
+    QObject::connect(this, &Post::contentChanged, [this]() {
+        QJsonObject obj = QJsonDocument::fromJson(mJsonString.toUtf8()).object();
+        obj["content"] = QJsonValue(mContent);
+        QJsonDocument doc(obj);
+        QString result(doc.toJson(QJsonDocument::Indented));
+        mJsonString = result;
+        emit jsonStringChanged(mJsonString);
+    });
+
+    cacheImgs();
+}
+
+Post::~Post()
+{
+
+}
+
+void Post::populateFromJson(QJsonObject post)
 {
     mTitle = html2text(post.value("title").toString().trimmed());
     mFeedTitle = html2text(post.value("feed_title").toString().trimmed());
@@ -50,11 +77,6 @@ Post::Post(QJsonObject post, QObject *parent) : QObject(parent)
     mJsonString = result;
 }
 
-Post::~Post()
-{
-
-}
-
 void Post::setRead(bool r)
 {
     if(mRead == r) return;
@@ -77,3 +99,42 @@ QString Post::html2text(const QString htmlString)
     doc.setHtml(htmlString);
     return doc.toPlainText();
 }
+
+void Post::cacheImgs()
+{
+    QRegExp imgTagRegex("\\<img[^\\>]*src\\s*=\\s*\"([^\"]*)\"[^\\>]*\\>", Qt::CaseInsensitive);
+    imgTagRegex.setMinimal(true);
+    QStringList urlmatches;
+    int offset = 0;
+    while( (offset = imgTagRegex.indexIn(mContent, offset)) != -1){
+        offset += imgTagRegex.matchedLength();
+        urlmatches.append(imgTagRegex.cap(1)); // Should hold only src property
+    }
+
+    for(QString url : urlmatches) {
+
+        if(url.startsWith("http")) {
+            QNetworkRequest request(url);
+            QNetworkReply *reply = mNetworkManager->get(request);
+
+            connect(reply, &QNetworkReply::finished, [url, this, reply] () {
+                if (reply) {
+                    if (reply->error() == QNetworkReply::NoError) {
+                        QVariant mimeType(reply->header(QNetworkRequest::ContentTypeHeader));
+                        QString imgString = QString("data:") + mimeType.toString() + QString(";base64,") + QString(reply->readAll().toBase64());
+                        if(mimeType == "image/jpeg" || mimeType == "image/gif" || mimeType == "image/png")
+                        {
+                            mContent = mContent.replace(url, imgString);
+                            emit contentChanged(mContent);
+                        }
+                    } else {
+                        int httpStatus = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
+                        //do some error management
+                        qWarning() << "HTTP error: " << httpStatus;
+                    }
+                    reply->deleteLater();
+                }
+            });
+        }
+    }
+}

src/post.h

@@ -24,6 +24,7 @@
 #include <QUrl>
 #include <QDate>
 #include <QJsonObject>
+#include <QNetworkReply>
 
 class Post : public QObject
 {
@@ -35,16 +36,17 @@ class Post : public QObject
     Q_PROPERTY(QString author READ author CONSTANT)
     Q_PROPERTY(QUrl link READ link CONSTANT)
     Q_PROPERTY(QDateTime date READ date CONSTANT)
-    Q_PROPERTY(QString content READ content CONSTANT)
+    Q_PROPERTY(QString content READ content NOTIFY contentChanged)
     Q_PROPERTY(QString excerpt READ excerpt CONSTANT)
     Q_PROPERTY(bool starred READ starred NOTIFY starredChanged)
     Q_PROPERTY(bool read READ read WRITE setRead NOTIFY readChanged)
     Q_PROPERTY(bool dontChangeRead READ dontChangeRead WRITE setDontChangeRead NOTIFY dontChangeReadChanged)
-    Q_PROPERTY(QString jsonString READ jsonString CONSTANT)
+    Q_PROPERTY(QString jsonString READ jsonString NOTIFY jsonStringChanged)
 
 public:
     Post(QObject *parent = 0);
     Post(QJsonObject post, QObject *parent = 0);
+    Post(QJsonObject post, QNetworkAccessManager *networkManager, QObject *parent = 0);
     ~Post();
     QString title() const { return mTitle; }
     QString feedTitle() const { return mFeedTitle; }
@@ -63,9 +65,11 @@ public:
     QString jsonString() const { return mJsonString; }
 
 signals:
+    void contentChanged(QString);
     void starredChanged(bool);
     void readChanged(bool);
     void dontChangeReadChanged(bool);
+    void jsonStringChanged(QString);
 
 public slots:
 
@@ -83,7 +87,11 @@ private:
     bool mRead;
     bool mDontChangeRead;
     QString mJsonString;
+
     QString html2text(const QString htmlString);
+    void cacheImgs();
+    void populateFromJson(QJsonObject post);
+    QNetworkAccessManager *mNetworkManager;
 };
 
 #endif // POST_H

src/tinytinyrss.cpp

@@ -62,7 +62,7 @@ void TinyTinyRSS::reload()
         for(int i = 0; i < posts.count(); i++)
         {
             QJsonObject postJson = posts.at(i).toObject();
-            Post *post = new Post(postJson, this);
+            Post *post = new Post(postJson, mNetworkManager, this);
             connect(post, SIGNAL(readChanged(bool)), this, SLOT(onPostReadChanged(bool)));
             mPosts.append(post);
         }