dbhub: Send last modified date when pushing database

Also add some code for receiving the last modified data when fetching
but we're not yet able to set it.

src/RemoteDatabase.cpp

@@ -12,6 +12,7 @@
#include <QJsonDocument>
#include <QJsonObject>
#include <QHttpMultiPart>
#include <QTimeZone>

#include "RemoteDatabase.h"
#include "version.h"
@@ -150,6 +151,17 @@ void RemoteDatabase::gotReply(QNetworkReply* reply)
            file.write(reply->readAll());
            file.close();

            // Set last modified data of the new file to the one provided by the server
            // TODO Qt doesn't offer any option to set this attribute, so we'd need to figure out a way to do it
            // ourselves in a platform-independent way.
            /*QString last_modified = reply->rawHeader("Content-Disposition");
            QRegExp regex("^.*modification-date=\"(.+)\";.*$");
            regex.setMinimal(true); // Set to non-greedy matching
            if(regex.indexIn(last_modified) != -1)
            {
                last_modified = regex.cap(1);
            }*/

            // Tell the application to open this file
            emit openFile(saveFileAs);
        }
@@ -437,6 +449,11 @@ void RemoteDatabase::push(const QString& filename, const QString& url, const QSt
    request.setUrl(url);
    request.setRawHeader("User-Agent", QString("%1 %2").arg(qApp->organizationName()).arg(APP_VERSION).toUtf8());

    // Get the last modified date of the file and prepare it for conversion into the ISO date format
    QDateTime last_modified = QFileInfo(filename).lastModified();
    last_modified.setTimeSpec(Qt::OffsetFromUTC);
    last_modified.setTimeZone(QTimeZone::systemTimeZone());

    // Prepare HTTP multi part data containing all the information about the commit we're about to push
    QHttpMultiPart* multipart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
    addPart(multipart, "file", file, remotename);
@@ -446,6 +463,7 @@ void RemoteDatabase::push(const QString& filename, const QString& url, const QSt
    addPart(multipart, "branch", branch);
    addPart(multipart, "commit", localLastCommitId(filename));
    addPart(multipart, "force", forcePush ? "true" : "false");
    addPart(multipart, "lastmodified", last_modified.toString(Qt::ISODate));

    // Set SSL configuration when trying to access a file via the HTTPS protocol
    bool https = QUrl(url).scheme().compare("https", Qt::CaseInsensitive) == 0;