C++ QNetworkCacheMetaData::expirationDate方法代码示例

void QNetworkCacheMetaDataPrivate::save(QDataStream &out, const QNetworkCacheMetaData &metaData)
{
    // note: if you change the contents of the meta data here
    // remember to bump the cache version in qnetworkdiskcache.cpp CurrentCacheVersion
    out << metaData.url();
    out << metaData.expirationDate();
    out << metaData.lastModified();
    out << metaData.saveToDisk();
    out << metaData.attributes();
    out << metaData.rawHeaders();
}

int main(int argc, char **argv)
{
    QCoreApplication application(argc, argv);
    QCoreApplication::setOrganizationDomain(QLatin1String("sites.google.com/site/zeromusparadoxe01"));
    QCoreApplication::setApplicationName(QLatin1String("zBrowser"));

    QStringList args = application.arguments();
    args.takeFirst();
    if (args.isEmpty()) {
        QTextStream stream(stdout);
        stream << "zbrowser-cacheinfo is a tool for viewing and extracting information out of zBrowser cache files." << endl;
        stream << "zbrowser-cacheinfo [-o cachefile] [file | url]" << endl;
        return 0;
    }

    NetworkDiskCache diskCache;
    QString location = QDesktopServices::storageLocation(QDesktopServices::CacheLocation)
            + QLatin1String("/browser/");
    diskCache.setCacheDirectory(location);

    QNetworkCacheMetaData metaData;
    QString last = args.takeLast();
    if (QFile::exists(last)) {
        qDebug() << "Reading in from a file and not a URL.";
        metaData = diskCache._fileMetaData(last);
    } else {
        qDebug() << "Reading in from a URL and not a file.";
        metaData = diskCache.metaData(last);
    }

    if (!args.isEmpty()
        && args.count() >= 1
        && args.first() == QLatin1String("-o")) {
        QUrl url = metaData.url();
        QIODevice *device = diskCache.data(url);
        if (!device) {
            qDebug() << "Error: data for URL is 0!";
            return 1;
        }
        QString fileName;
        if (args.count() == 2) {
            fileName = args.last();
        } else {
            QFileInfo info(url.path());
            fileName = info.fileName();
            if (fileName.isEmpty()) {
                qDebug() << "URL file name is empty, please specify an output file, I wont guess.";
                return 1;
            }
            if (QFile::exists(fileName)) {
                qDebug() << "File already exists, not overwriting, please specify an output file.";
                return 1;
            }
        }
        qDebug() << "Saved cache file to:" << fileName;
        QFile file(fileName);
        if (!file.open(QFile::ReadWrite))
            qDebug() << "Unable to open the output file for writing.";
        else
            file.write(device->readAll());
        delete device;
    }

    QTextStream stream(stdout);
    stream << "URL: " << metaData.url().toString() << endl;
    stream << "Expiration Date: " << metaData.expirationDate().toString() << endl;
    stream << "Last Modified Date: " << metaData.lastModified().toString() << endl;
    stream << "Save to disk: " << metaData.saveToDisk() << endl;
    stream << "Headers:" << endl;
    foreach (const QNetworkCacheMetaData::RawHeader &header, metaData.rawHeaders())
        stream << "\t" << header.first << ": " << header.second << endl;
    QIODevice *device = diskCache.data(metaData.url());
    if (device) {
        stream << "Data Size: " << device->size() << endl;
        stream << "First line: " << device->readLine(100);
    } else {
        stream << "No data? Either the file is corrupt or there is an error." << endl;
    }

    delete device;
    return 0;
}

/** \brief Downloads a QNetworkRequest via the QNetworkAccessManager
 *  \param dlInfo   MythDownloadInfo information for download
 */
void MythDownloadManager::downloadQNetworkRequest(MythDownloadInfo *dlInfo)
{
    if (!dlInfo)
        return;

    static const char dateFormat[] = "ddd, dd MMM yyyy hh:mm:ss 'GMT'";
    QUrl qurl(dlInfo->m_url);
    QNetworkRequest request;

    if (dlInfo->m_request)
    {
        request = *dlInfo->m_request;
        delete dlInfo->m_request;
        dlInfo->m_request = NULL;
    }
    else
        request.setUrl(qurl);

    if (!dlInfo->m_reload)
    {
        // Prefer the in-cache item if one exists and it is less than 5 minutes
        // old and it will not expire in the next 10 seconds
        QDateTime now = MythDate::current();

        // Handle redirects, we want the metadata of the file headers
        QString redirectLoc;
        int limit = 0;
        while (!(redirectLoc = getHeader(qurl, "Location")).isNull())
        {
            if (limit == CACHE_REDIRECTION_LIMIT)
            {
                LOG(VB_GENERAL, LOG_WARNING, QString("Cache Redirection limit "
                                                     "reached for %1")
                                                    .arg(qurl.toString()));
                return;
            }
            qurl.setUrl(redirectLoc);
            limit++;
        }

        LOG(VB_NETWORK, LOG_DEBUG, QString("Checking cache for %1")
                                                    .arg(qurl.toString()));

        m_infoLock->lock();
        QNetworkCacheMetaData urlData = m_manager->cache()->metaData(qurl);
        m_infoLock->unlock();
        if ((urlData.isValid()) &&
            ((!urlData.expirationDate().isValid()) ||
             (QDateTime(urlData.expirationDate().toUTC()).secsTo(now) < 10)))
        {
            QString dateString = getHeader(urlData, "Date");

            if (!dateString.isNull())
            {
                QDateTime loadDate =
                    MythDate::fromString(dateString, dateFormat);
                loadDate.setTimeSpec(Qt::UTC);
                if (loadDate.secsTo(now) <= 720)
                {
                    dlInfo->m_preferCache = true;
                    LOG(VB_NETWORK, LOG_DEBUG, QString("Prefering cache for %1")
                                                    .arg(qurl.toString()));
                }
            }
        }
    }

    if (dlInfo->m_preferCache)
        request.setAttribute(QNetworkRequest::CacheLoadControlAttribute,
                             QNetworkRequest::PreferCache);

    request.setRawHeader("User-Agent",
                         "MythTV v" MYTH_BINARY_VERSION " MythDownloadManager");

    if (dlInfo->m_headers)
    {
        QHash<QByteArray, QByteArray>::const_iterator it =
            dlInfo->m_headers->constBegin();
        for ( ; it != dlInfo->m_headers->constEnd(); ++it )
        {
            if (!it.key().isEmpty() && !it.value().isEmpty())
            {
                request.setRawHeader(it.key(), it.value());
            }
        }
    }

    switch (dlInfo->m_requestType)
    {
        case kRequestPost :
            dlInfo->m_reply = m_manager->post(request, *dlInfo->m_data);
            break;
        case kRequestHead :
            dlInfo->m_reply = m_manager->head(request);
            break;
        case kRequestGet :
        default:
//.........这里部分代码省略.........

/** \fn MythDownloadManager::downloadQNetworkRequest(MythDownloadInfo *dlInfo)
 *  \brief Downloads a QNetworkRequest via the QNetworkAccessManager
 *  \param dlInfo   MythDownloadInfo information for download
 */
void MythDownloadManager::downloadQNetworkRequest(MythDownloadInfo *dlInfo)
{
    static const char dateFormat[] = "ddd, dd MMM yyyy hh:mm:ss 'GMT'";
    QUrl qurl(dlInfo->m_url);
    QNetworkRequest request;
    
    if (dlInfo->m_request)
    {
        request = *dlInfo->m_request;
        delete dlInfo->m_request;
        dlInfo->m_request = NULL;
    }
    else
        request.setUrl(qurl);

    if (!dlInfo->m_reload)
    {
        // Prefer the in-cache item if one exists and it is less than 60
        // seconds old and has not expired in the last 10 seconds.
        QDateTime now = QDateTime::currentDateTime();
        QNetworkCacheMetaData urlData = m_manager->cache()->metaData(qurl);
        if ((urlData.isValid()) &&
            ((!urlData.expirationDate().isValid()) ||
             (urlData.expirationDate().secsTo(now) < 10)))
        {
            QNetworkCacheMetaData::RawHeaderList headers =
                urlData.rawHeaders();
            bool found = false;
            QNetworkCacheMetaData::RawHeaderList::iterator it
                = headers.begin();
            for (; !found && it != headers.end(); ++it)
            {
                if ((*it).first == "Date")
                {
                    found = true;
                    QDateTime loadDate =
                       QDateTime::fromString((*it).second, dateFormat);
                    loadDate.setTimeSpec(Qt::UTC);
                    if (loadDate.secsTo(now) < 60)
                        dlInfo->m_preferCache = true;
                }
            }
        }
    }

    if (dlInfo->m_preferCache)
        request.setAttribute(QNetworkRequest::CacheLoadControlAttribute,
                             QNetworkRequest::PreferCache);

    request.setRawHeader("User-Agent",
                         "MythDownloadManager v" MYTH_BINARY_VERSION);

    if (dlInfo->m_post)
        dlInfo->m_reply = m_manager->post(request, *dlInfo->m_data);
    else
        dlInfo->m_reply = m_manager->get(request);

    m_downloadReplies[dlInfo->m_reply] = dlInfo;

    connect(dlInfo->m_reply, SIGNAL(error(QNetworkReply::NetworkError)), this,
            SLOT(downloadError(QNetworkReply::NetworkError)));
    connect(dlInfo->m_reply, SIGNAL(downloadProgress(qint64, qint64)),
            this, SLOT(downloadProgress(qint64, qint64))); 
}

void QgsWfsRequest::replyFinished()
{
  if ( !mIsAborted && mReply )
  {
    if ( mReply->error() == QNetworkReply::NoError )
    {
      QgsDebugMsgLevel( QStringLiteral( "reply OK" ), 4 );
      QVariant redirect = mReply->attribute( QNetworkRequest::RedirectionTargetAttribute );
      if ( !redirect.isNull() )
      {
        QgsDebugMsgLevel( QStringLiteral( "Request redirected." ), 4 );

        const QUrl &toUrl = redirect.toUrl();
        mReply->request();
        if ( toUrl == mReply->url() )
        {
          mErrorMessage = tr( "Redirect loop detected: %1" ).arg( toUrl.toString() );
          QgsMessageLog::logMessage( mErrorMessage, tr( "WFS" ) );
          mResponse.clear();
        }
        else
        {
          QNetworkRequest request( toUrl );
          QgsSetRequestInitiatorClass( request, QStringLiteral( "QgsWfsRequest" ) );
          if ( !mUri.auth().setAuthorization( request ) )
          {
            mResponse.clear();
            mErrorMessage = errorMessageFailedAuth();
            mErrorCode = QgsWfsRequest::NetworkError;
            QgsMessageLog::logMessage( mErrorMessage, tr( "WFS" ) );
            emit downloadFinished();
            return;
          }
          request.setAttribute( QNetworkRequest::CacheLoadControlAttribute, mForceRefresh ? QNetworkRequest::AlwaysNetwork : QNetworkRequest::PreferCache );
          request.setAttribute( QNetworkRequest::CacheSaveControlAttribute, true );

          mReply->deleteLater();
          mReply = nullptr;

          QgsDebugMsgLevel( QStringLiteral( "redirected: %1 forceRefresh=%2" ).arg( redirect.toString() ).arg( mForceRefresh ), 4 );
          mReply = QgsNetworkAccessManager::instance()->get( request );
          mReply->setReadBufferSize( READ_BUFFER_SIZE_HINT );
          if ( !mUri.auth().setAuthorizationReply( mReply ) )
          {
            mResponse.clear();
            mErrorMessage = errorMessageFailedAuth();
            mErrorCode = QgsWfsRequest::NetworkError;
            QgsMessageLog::logMessage( mErrorMessage, tr( "WFS" ) );
            emit downloadFinished();
            return;
          }
          connect( mReply, &QNetworkReply::finished, this, &QgsWfsRequest::replyFinished, Qt::DirectConnection );
          connect( mReply, &QNetworkReply::downloadProgress, this, &QgsWfsRequest::replyProgress, Qt::DirectConnection );
          return;
        }
      }
      else
      {
        const QgsNetworkAccessManager *nam = QgsNetworkAccessManager::instance();

        if ( nam->cache() )
        {
          QNetworkCacheMetaData cmd = nam->cache()->metaData( mReply->request().url() );

          QNetworkCacheMetaData::RawHeaderList hl;
          const auto constRawHeaders = cmd.rawHeaders();
          for ( const QNetworkCacheMetaData::RawHeader &h : constRawHeaders )
          {
            if ( h.first != "Cache-Control" )
              hl.append( h );
          }
          cmd.setRawHeaders( hl );

          QgsDebugMsgLevel( QStringLiteral( "expirationDate:%1" ).arg( cmd.expirationDate().toString() ), 4 );
          if ( cmd.expirationDate().isNull() )
          {
            cmd.setExpirationDate( QDateTime::currentDateTime().addSecs( defaultExpirationInSec() ) );
          }

          nam->cache()->updateMetaData( cmd );
        }
        else
        {
          QgsDebugMsgLevel( QStringLiteral( "No cache!" ), 4 );
        }

#ifdef QGISDEBUG
        bool fromCache = mReply->attribute( QNetworkRequest::SourceIsFromCacheAttribute ).toBool();
        QgsDebugMsgLevel( QStringLiteral( "Reply was cached: %1" ).arg( fromCache ), 4 );
#endif

        mResponse = mReply->readAll();

        if ( mResponse.isEmpty() && !mGotNonEmptyResponse )
        {
          mErrorMessage = tr( "empty response: %1" ).arg( mReply->errorString() );
          mErrorCode = QgsWfsRequest::ServerExceptionError;
          QgsMessageLog::logMessage( mErrorMessage, tr( "WFS" ) );
        }
      }
//.........这里部分代码省略.........

/*
    For a given httpRequest
    1) If AlwaysNetwork, return
    2) If we have a cache entry for this url populate headers so the server can return 304
    3) Calculate if response_is_fresh and if so send the cache and set loadedFromCache to true
 */
bool QNetworkAccessHttpBackend::loadFromCacheIfAllowed(QHttpNetworkRequest &httpRequest)
{
    QNetworkRequest::CacheLoadControl CacheLoadControlAttribute =
        (QNetworkRequest::CacheLoadControl)request().attribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::PreferNetwork).toInt();
    if (CacheLoadControlAttribute == QNetworkRequest::AlwaysNetwork) {
        // If the request does not already specify preferred cache-control
        // force reload from the network and tell any caching proxy servers to reload too
        if (!request().rawHeaderList().contains("Cache-Control")) {
            httpRequest.setHeaderField("Cache-Control", "no-cache");
            httpRequest.setHeaderField("Pragma", "no-cache");
        }
        return false;
    }

    // The disk cache API does not currently support partial content retrieval.
    // That is why we don't use the disk cache for any such requests.
    if (request().hasRawHeader("Range"))
        return false;

    QAbstractNetworkCache *nc = networkCache();
    if (!nc)
        return false;                 // no local cache

    QNetworkCacheMetaData metaData = nc->metaData(url());
    if (!metaData.isValid())
        return false;                 // not in cache

    if (!metaData.saveToDisk())
        return false;

    QNetworkHeadersPrivate cacheHeaders;
    QNetworkHeadersPrivate::RawHeadersList::ConstIterator it;
    cacheHeaders.setAllRawHeaders(metaData.rawHeaders());

    it = cacheHeaders.findRawHeader("etag");
    if (it != cacheHeaders.rawHeaders.constEnd())
        httpRequest.setHeaderField("If-None-Match", it->second);

    QDateTime lastModified = metaData.lastModified();
    if (lastModified.isValid())
        httpRequest.setHeaderField("If-Modified-Since", QNetworkHeadersPrivate::toHttpDate(lastModified));

    it = cacheHeaders.findRawHeader("Cache-Control");
    if (it != cacheHeaders.rawHeaders.constEnd()) {
        QHash<QByteArray, QByteArray> cacheControl = parseHttpOptionHeader(it->second);
        if (cacheControl.contains("must-revalidate"))
            return false;
    }

    QDateTime currentDateTime = QDateTime::currentDateTime();
    QDateTime expirationDate = metaData.expirationDate();

#if 0
    /*
     * age_value
     *      is the value of Age: header received by the cache with
     *              this response.
     * date_value
     *      is the value of the origin server's Date: header
     * request_time
     *      is the (local) time when the cache made the request
     *              that resulted in this cached response
     * response_time
     *      is the (local) time when the cache received the
     *              response
     * now
     *      is the current (local) time
     */
    int age_value = 0;
    it = cacheHeaders.findRawHeader("age");
    if (it != cacheHeaders.rawHeaders.constEnd())
        age_value = it->second.toInt();

    QDateTime dateHeader;
    int date_value = 0;
    it = cacheHeaders.findRawHeader("date");
    if (it != cacheHeaders.rawHeaders.constEnd()) {
        dateHeader = QNetworkHeadersPrivate::fromHttpDate(it->second);
        date_value = dateHeader.toTime_t();
    }

    int now = currentDateTime.toUTC().toTime_t();
    int request_time = now;
    int response_time = now;

    // Algorithm from RFC 2616 section 13.2.3
    int apparent_age = qMax(0, response_time - date_value);
    int corrected_received_age = qMax(apparent_age, age_value);
    int response_delay = response_time - request_time;
    int corrected_initial_age = corrected_received_age + response_delay;
    int resident_time = now - response_time;
    int current_age   = corrected_initial_age + resident_time;

    // RFC 2616 13.2.4 Expiration Calculations
//.........这里部分代码省略.........