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QNetworkDiskCache: fix expiration calculation heuristic with Last-Modified time 

Heuristic with last-modified time in Qt has some problems.
1) Remove redundant expirationDate.isInvalid() check
expirationDate.isInvalid is already checked. So I removed.

2) Add dateHeader.isInvalid() check
The dateHeader is used in expiration calculation.
I add invalid check for the dateHeader.
*. The dateHeader is the origin server's Date

3) Change diff time calculation.
The expirationDate is calculated with time diff.

Previous calculation is
// The lastModified is earlier than the currentDateTime.
// The diff has negative value.
int diff = currentDateTime.secsTo(lastModified);
// The expirationDate is earlier than lastModified
// , currentDateTime and dateHeader.
expirationDate = lastModified.addSecs(diff / 10);
*. currentDateTime: current time
*. lastModified: last modified date in server

It means that files are not cached with the heuristic.

I changed diff calculation.
int diff = lastModified.secsTo(dateHeader);
freshness_lifetime = diff / 10; // RFC 2616 13.2.4

4) httpRequest.headerField setting
If current_age is larger than 1 day, the cache MUST attach Warning 113.
*. The current_age is value of age in header
   or elapsed time from dateHeader in Qt source code.

Previous code does not check current_age is larger than 1 day correctly.
// dt = 1970-01-01T00:00:00 + current_age
dt.setTime_t(current_age);
// currentDateTime is much bigger than 1970-01-01T00:00:00
if (dt.daysTo(currentDateTime) > 1)

Task-number: QTBUG-40836
Change-Id: I4b00c3b287e6fafeea6b02681533fe75a198247e
Reviewed-by: Jung Dong-Heon <dongheon.jung@lge.com>
Reviewed-by: Peter Hartmann <phartmann@blackberry.com>
bb10
Dong-Heon Jung 2014-08-18 12:58:56 +09:00 committed by Jung Dong-Heon
parent f1093e06b2
commit 992baedb8b
2 changed files with 13 additions and 15 deletions
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24
src/network/access/qnetworkreplyhttpimpl.cpp
View File

@ -560,23 +560,21 @@ bool QNetworkReplyHttpImplPrivate::loadFromCacheIfAllowed(QHttpNetworkRequest &h
int resident_time = now - response_time;
int current_age = corrected_initial_age + resident_time;
int freshness_lifetime = 0;
// RFC 2616 13.2.4 Expiration Calculations
if (!expirationDate.isValid()) {
if (lastModified.isValid()) {
int diff = currentDateTime.secsTo(lastModified);
expirationDate = lastModified.addSecs(diff / 10);
if (httpRequest.headerField("Warning").isEmpty()) {
QDateTime dt;
dt.setTime_t(current_age);
if (dt.daysTo(currentDateTime) > 1)
httpRequest.setHeaderField("Warning", "113");
}
if (lastModified.isValid() && dateHeader.isValid()) {
int diff = lastModified.secsTo(dateHeader);
freshness_lifetime = diff / 10;
if (httpRequest.headerField("Warning").isEmpty()) {
QDateTime dt = currentDateTime.addSecs(current_age);
if (currentDateTime.daysTo(dt) > 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);
// the cache-saving code below sets the freshness_lifetime with (dateHeader - last_modified) / 10
// if "last-modified" is present, or to Expires otherwise
response_is_fresh = (freshness_lifetime > current_age);
} else {
// expiration date was calculated earlier (e.g. when storing object to the cache)

4
tests/auto/network/access/qabstractnetworkcache/tst_qabstractnetworkcache.cpp
View File

@ -203,9 +203,9 @@ void tst_QAbstractNetworkCache::lastModified_data()
QTest::newRow("304-3") << QNetworkRequest::PreferCache << "httpcachetest_lastModified304.cgi" << true;
QTest::newRow("200-0") << QNetworkRequest::AlwaysNetwork << "httpcachetest_lastModified200.cgi" << AlwaysFalse;
QTest::newRow("200-1") << QNetworkRequest::PreferNetwork << "httpcachetest_lastModified200.cgi" << false;
QTest::newRow("200-1") << QNetworkRequest::PreferNetwork << "httpcachetest_lastModified200.cgi" << true;
QTest::newRow("200-2") << QNetworkRequest::AlwaysCache << "httpcachetest_lastModified200.cgi" << AlwaysTrue;
QTest::newRow("200-3") << QNetworkRequest::PreferCache << "httpcachetest_lastModified200.cgi" << false;
QTest::newRow("200-3") << QNetworkRequest::PreferCache << "httpcachetest_lastModified200.cgi" << true;
}
void tst_QAbstractNetworkCache::lastModified()