/*
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
*/
void QNetworkAccessHttpBackend::validateCache(QHttpNetworkRequest &httpRequest, bool &loadedFromCache)
{
QNetworkRequest::CacheLoadControl CacheLoadControlAttribute =
(QNetworkRequest::CacheLoadControl)request().attribute(QNetworkRequest::CacheLoadControlAttribute, QNetworkRequest::PreferNetwork).toInt();
if (CacheLoadControlAttribute == QNetworkRequest::AlwaysNetwork) {
// forced reload from the network
// tell any caching proxy servers to reload too
httpRequest.setHeaderField("Cache-Control", "no-cache");
httpRequest.setHeaderField("Pragma", "no-cache");
return;
}
QAbstractNetworkCache *nc = networkCache();
if (!nc)
return; // no local cache
QNetworkCacheMetaData metaData = nc->metaData(url());
if (!metaData.isValid())
return; // not in cache
if (!metaData.saveToDisk())
return;
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));
if (CacheLoadControlAttribute == QNetworkRequest::PreferNetwork) {
it = cacheHeaders.findRawHeader("Cache-Control");
if (it != cacheHeaders.rawHeaders.constEnd()) {
QHash<QByteArray, QByteArray> cacheControl = parseHttpOptionHeader(it->second);
if (cacheControl.contains("must-revalidate"))
return;
}
}
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
if (!expirationDate.isValid()) {
if (lastModified.isValid()) {
int diff = currentDateTime.secsTo(lastModified);
expirationDate = lastModified;
expirationDate.addSecs(diff / 10);
if (httpRequest.headerField("Warning").isEmpty()) {
QDateTime dt;
dt.setTime_t(current_age);
if (dt.daysTo(currentDateTime) > 1)
httpRequest.setHeaderField("Warning", "113");
}
}
}
// the cache-saving code below sets the expirationDate with date+max_age
// if "max-age" is present, or to Expires otherwise
int freshness_lifetime = dateHeader.secsTo(expirationDate);
bool response_is_fresh = (freshness_lifetime > current_age);
#else
bool response_is_fresh = currentDateTime.secsTo(expirationDate) >= 0;
#endif
if (!response_is_fresh)
return;
loadedFromCache = true;
#if defined(QNETWORKACCESSHTTPBACKEND_DEBUG)
qDebug() << "response_is_fresh" << CacheLoadControlAttribute;
#endif
if (!sendCacheContents(metaData))
loadedFromCache = false;
}
/** \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:
dlInfo->m_reply = m_manager->get(request);
break;
}
m_downloadReplies[dlInfo->m_reply] = dlInfo;
if (dlInfo->m_authCallback)
{
connect(m_manager, SIGNAL(authenticationRequired(QNetworkReply *,
QAuthenticator *)),
this, SLOT(authCallback(QNetworkReply *, QAuthenticator *)));
}
void tst_QNetworkCacheMetaData::qnetworkcachemetadata()
{
QNetworkCacheMetaData data;
QCOMPARE(data.expirationDate(), QDateTime());
QCOMPARE(data.isValid(), false);
QCOMPARE(data.lastModified(), QDateTime());
QCOMPARE(data.operator!=(QNetworkCacheMetaData()), false);
QNetworkCacheMetaData metaData;
QCOMPARE(data.operator=(metaData), QNetworkCacheMetaData());
QCOMPARE(data.operator==(QNetworkCacheMetaData()), true);
QCOMPARE(data.rawHeaders(), QNetworkCacheMetaData::RawHeaderList());
QCOMPARE(data.saveToDisk(), true);
QCOMPARE(data.url(), QUrl());
data.setExpirationDate(QDateTime());
data.setLastModified(QDateTime());
data.setRawHeaders(QNetworkCacheMetaData::RawHeaderList());
data.setSaveToDisk(false);
data.setUrl(QUrl());
}