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

void
WMSRequester::requestTile(const TileBuildOperation& op)
{
    QUrl url(op.urlString);

    // Testing the 'SourceIsFromCache' attribute of replies from the OnEarth server
    // seems to indicate that the tiles are not being cached. However, tiles are still
    // appearing in the cache directory. The following code attempts to force using
    // the cache, but may not be effective.
    QNetworkCacheMetaData cacheData = m_networkManager->cache()->metaData(url);
    QNetworkRequest request(url);
    if (cacheData.isValid())
    {
        request.setAttribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::AlwaysCache);
    }
    else
    {
        request.setAttribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::PreferCache);
    }

    QNetworkReply* reply = m_networkManager->get(request);

    m_mutex.lock();
    m_dispatchedRequestCount++;
    m_requestedTiles[reply] = op;
    m_mutex.unlock();
}

/** \fn MythDownloadManager::GetLastModified(const QString &url)
 *  \brief Gets the Last Modified timestamp for a URI
 *  \param url    URI to test.
 *  \return Timestamp the URI was last modified or now if an error occurred
 */
QDateTime MythDownloadManager::GetLastModified(const QString &url)
{
    static const char dateFormat[] = "ddd, dd MMM yyyy hh:mm:ss 'GMT'";
    VERBOSE(VB_FILE+VB_EXTRA, LOC + QString("GetLastModified('%1')").arg(url));
    QDateTime result;

    QDateTime now = QDateTime::currentDateTime();
    QNetworkCacheMetaData urlData = m_manager->cache()->metaData(QUrl(url));

    if (urlData.isValid())
    {
        if (urlData.lastModified().secsTo(now) <= 60)
        {
            result = urlData.lastModified();
        }
        else
        {
            // If the last modification date is older than 60 seconds, and
            // we loaded the page over 60 seconds ago, then redownload the
            // page to re-verify it's last modified date.
            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)
                        result = urlData.lastModified();
                }
            }
        }
    }

    if (!result.isValid())
    {
        MythDownloadInfo *dlInfo = new MythDownloadInfo;
        dlInfo->m_url      = url;
        dlInfo->m_syncMode = true;

        if (downloadNow(dlInfo, false) && dlInfo->m_reply)
        {
            QVariant lastMod =
                dlInfo->m_reply->header(QNetworkRequest::LastModifiedHeader);
            if (lastMod.isValid())
                result = lastMod.toDateTime();
        }

        delete dlInfo;
    }

    return result;
}

bool QNetworkAccessCacheBackend::sendCacheContents()
{
    setCachingEnabled(false);
    QAbstractNetworkCache *nc = networkCache();
    if (!nc)
        return false;

    QNetworkCacheMetaData item = nc->metaData(url());
    if (!item.isValid())
        return false;

    QNetworkCacheMetaData::AttributesMap attributes = item.attributes();
    setAttribute(QNetworkRequest::HttpStatusCodeAttribute, attributes.value(QNetworkRequest::HttpStatusCodeAttribute));
    setAttribute(QNetworkRequest::HttpReasonPhraseAttribute, attributes.value(QNetworkRequest::HttpReasonPhraseAttribute));

    // set the raw headers
    QNetworkCacheMetaData::RawHeaderList rawHeaders = item.rawHeaders();
    QNetworkCacheMetaData::RawHeaderList::ConstIterator it = rawHeaders.constBegin(),
                                                       end = rawHeaders.constEnd();
    for ( ; it != end; ++it) {
        if (it->first.toLower() == "cache-control" &&
            it->second.toLower().contains("must-revalidate")) {
            return false;
        }
        setRawHeader(it->first, it->second);
    }

    // handle a possible redirect
    QVariant redirectionTarget = attributes.value(QNetworkRequest::RedirectionTargetAttribute);
    if (redirectionTarget.isValid()) {
        setAttribute(QNetworkRequest::RedirectionTargetAttribute, redirectionTarget);
        redirectionRequested(redirectionTarget.toUrl());
    }

    // signal we're open
    metaDataChanged();

    if (operation() == QNetworkAccessManager::GetOperation) {
        QIODevice *contents = nc->data(url());
        if (!contents)
            return false;
        contents->setParent(this);
        writeDownstreamData(contents);
    }

#if defined(QNETWORKACCESSCACHEBACKEND_DEBUG)
    qDebug() << "Successfully sent cache:" << url();
#endif
    return true;
}

//Times metadata as well payload lookup
// i.e metaData(), rawHeaders() and data()
void tst_qnetworkdiskcache::timeRead()
{

    QFETCH(QString, cacheRootDirectory);

    cacheDir = QString( cacheRootDirectory + QDir::separator() + "man_qndc");
    QDir d;
    qDebug() << "Setting cache directory to = " << d.absoluteFilePath(cacheDir);

    //Housekeeping
    cleanRecursive(cacheDir); // slow op.
    initCacheObject();
    cache->setCacheDirectory(cacheDir);
    cache->setMaximumCacheSize(qint64(HugeCacheLimit));
    cache->clear();

    //populate some fake data to simulate partially full cache
    injectFakeData();

    //Entries in the cache should be > what we try to remove
    QVERIFY(NumFakeCacheObjects > NumReadContent);

    //time metadata lookup of previously inserted URL.
    QBENCHMARK_ONCE {
        for (quint32 i = 0; i < NumReadContent; i++) {
            QString fakeURL;
            QTextStream stream(&fakeURL);
            stream << fakeURLbase << i;
            QUrl url(fakeURL);

            QNetworkCacheMetaData qndc = cache->metaData(url);
            QVERIFY(qndc.isValid()); // we must have read the metadata

            QNetworkCacheMetaData::RawHeaderList raw(qndc.rawHeaders());
            QVERIFY(raw.size()); // we must have parsed the headers from the meta

            QIODevice *iodevice(cache->data(url));
            QVERIFY(iodevice);    //must not be NULL
            iodevice->close();
            delete iodevice;
        }
    }

    //Cleanup (slow)
    cleanupCacheObject();
    cleanRecursive(cacheDir);

}

bool ResourceHandle::willLoadFromCache(ResourceRequest& request, Frame* frame)
{
    if (!frame)
        return false;

    QNetworkAccessManager* manager = QWebFramePrivate::kit(frame)->page()->networkAccessManager();
    QAbstractNetworkCache* cache = manager->cache();

    if (!cache)
        return false;

    QNetworkCacheMetaData data = cache->metaData(request.url());
    if (data.isValid()) {
        request.setCachePolicy(ReturnCacheDataDontLoad);
        return true;
    }

    return false;
}

bool ResourceHandle::willLoadFromCache(ResourceRequest& request, Frame* frame)
{
    if (!frame)
        return false;

    QNetworkAccessManager* manager = 0;
    QAbstractNetworkCache* cache = 0;
    if (frame->loader()->networkingContext()) {
        manager = frame->loader()->networkingContext()->networkAccessManager();
        cache = manager->cache();
    }

    if (!cache)
        return false;

    QNetworkCacheMetaData data = cache->metaData(request.url());
    if (data.isValid()) {
        request.setCachePolicy(ReturnCacheDataDontLoad);
        return true;
    }

    return false;
}

void NetworkCache::clearCache(int period)
{
	if (period <= 0)
	{
		clear();

		emit cleared();

		return;
	}

	const QDir cacheMainDirectory(cacheDirectory());
	const QStringList directories(cacheMainDirectory.entryList(QDir::AllDirs | QDir::NoDotAndDotDot));

	for (int i = 0; i < directories.count(); ++i)
	{
		const QDir cacheSubDirectory(cacheMainDirectory.absoluteFilePath(directories.at(i)));
		const QStringList subDirectories(cacheSubDirectory.entryList(QDir::AllDirs | QDir::NoDotAndDotDot));

		for (int j = 0; j < subDirectories.count(); ++j)
		{
			const QDir cacheFilesDirectory(cacheSubDirectory.absoluteFilePath(subDirectories.at(j)));
			const QStringList files(cacheFilesDirectory.entryList(QDir::Files));

			for (int k = 0; k < files.count(); ++k)
			{
				const QNetworkCacheMetaData metaData(fileMetaData(cacheFilesDirectory.absoluteFilePath(files.at(k))));

				if (metaData.isValid() && metaData.lastModified().isValid() && metaData.lastModified().secsTo(QDateTime::currentDateTime()) > (period * 3600))
				{
					remove(metaData.url());
				}
			}
		}
	}
}

/** \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))); 
}

/*
    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.........