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change(cache): use cache-specific http headers for their lifetime

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This uses the 'Age', 'Cache-Control' and 'Expires' HTTP headers to more
accurately set up the cache lifetime, falling back to a static 1-week
time if they're not present in the response.

Signed-off-by: flow <flowlnlnln@gmail.com>
This commit is contained in:
flow 2022-07-17 11:24:12 -03:00
parent c8a72c876d
commit ab6e1b112b
No known key found for this signature in database
GPG Key ID: 8D0F221F0A59F469
3 changed files with 53 additions and 9 deletions
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14
launcher/net/HttpMetaCache.cpp
View File

@ -44,11 +44,6 @@
#include <QDebug>
/** Maximum time to hold a cache entry
* = 1 week in milliseconds
*/
#define TIME_TO_EXPIRE 1*7*24*60*60*1000
auto MetaEntry::getFullPath() -> QString
{
// FIXME: make local?
@ -127,9 +122,8 @@ auto HttpMetaCache::resolveEntry(QString base, QString resource_path, QString ex
}
// Get rid of old entries, to prevent cache problems
auto current_time = QDateTime::currentMSecsSinceEpoch();
auto remote_time = QDateTime::fromString(entry->remote_changed_timestamp).toMSecsSinceEpoch();
if (current_time - remote_time < TIME_TO_EXPIRE) {
auto current_time = QDateTime::currentSecsSinceEpoch();
if (entry->isExpired(current_time - ( file_last_changed / 1000 ))) {
qWarning() << "Removing cache entry because of old age!";
selected_base.entry_list.remove(resource_path);
return staleEntry(base, resource_path);
@ -235,6 +229,8 @@ void HttpMetaCache::Load()
foo->etag = Json::ensureString(element_obj, "etag");
foo->local_changed_timestamp = Json::ensureDouble(element_obj, "last_changed_timestamp");
foo->remote_changed_timestamp = Json::ensureString(element_obj, "remote_changed_timestamp");
foo->current_age = Json::ensureDouble(element_obj, "current_age");
foo->max_age = Json::ensureDouble(element_obj, "max_age");
// presumed innocent until closer examination
foo->stale = false;
@ -275,6 +271,8 @@ void HttpMetaCache::SaveNow()
entryObj.insert("last_changed_timestamp", QJsonValue(double(entry->local_changed_timestamp)));
if (!entry->remote_changed_timestamp.isEmpty())
entryObj.insert("remote_changed_timestamp", QJsonValue(entry->remote_changed_timestamp));
entryObj.insert("current_age", QJsonValue(double(entry->current_age)));
entryObj.insert("max_age", QJsonValue(double(entry->max_age)));
entriesArr.append(entryObj);
}
}

10
launcher/net/HttpMetaCache.h
View File

@ -64,6 +64,14 @@ class MetaEntry {
auto getMD5Sum() -> QString { return md5sum; }
void setMD5Sum(QString md5sum) { this->md5sum = md5sum; }
auto getCurrentAge() -> qint64 { return current_age; }
void setCurrentAge(qint64 age) { current_age = age; }
auto getMaximumAge() -> qint64 { return max_age; }
void setMaximumAge(qint64 age) { max_age = age; }
bool isExpired(qint64 offset) { return current_age >= max_age - offset; };
protected:
QString baseId;
QString basePath;
@ -72,6 +80,8 @@ class MetaEntry {
QString etag;
qint64 local_changed_timestamp = 0;
QString remote_changed_timestamp; // QString for now, RFC 2822 encoded time
qint64 current_age = 0;
qint64 max_age = 0;
bool stale = true;
};

38
launcher/net/MetaCacheSink.cpp
View File

@ -36,11 +36,16 @@
#include "MetaCacheSink.h"
#include <QFile>
#include <QFileInfo>
#include "FileSystem.h"
#include "Application.h"
namespace Net {
/** Maximum time to hold a cache entry
* = 1 week in seconds
*/
#define MAX_TIME_TO_EXPIRE 1*7*24*60*60
MetaCacheSink::MetaCacheSink(MetaEntryPtr entry, ChecksumValidator * md5sum)
:Net::FileSink(entry->getFullPath()), m_entry(entry), m_md5Node(md5sum)
{
@ -88,6 +93,37 @@ Task::State MetaCacheSink::finalizeCache(QNetworkReply & reply)
}
m_entry->setLocalChangedTimestamp(output_file_info.lastModified().toUTC().toMSecsSinceEpoch());
{ // Cache lifetime
if (reply.hasRawHeader("Cache-Control")) {
auto cache_control_header = reply.rawHeader("Cache-Control");
// qDebug() << "[MetaCache] Parsing 'Cache-Control' header with" << cache_control_header;
QRegularExpression max_age_expr("max-age=([0-9]+)");
qint64 max_age = max_age_expr.match(cache_control_header).captured(1).toLongLong();
m_entry->setMaximumAge(max_age);
} else if (reply.hasRawHeader("Expires")) {
auto expires_header = reply.rawHeader("Expires");
// qDebug() << "[MetaCache] Parsing 'Expires' header with" << expires_header;
qint64 max_age = QDateTime::fromString(expires_header).toSecsSinceEpoch() - QDateTime::currentSecsSinceEpoch();
m_entry->setMaximumAge(max_age);
} else {
m_entry->setMaximumAge(MAX_TIME_TO_EXPIRE);
}
if (reply.hasRawHeader("Age")) {
auto age_header = reply.rawHeader("Age");
// qDebug() << "[MetaCache] Parsing 'Age' header with" << age_header;
qint64 current_age = age_header.toLongLong();
m_entry->setCurrentAge(current_age);
} else {
m_entry->setCurrentAge(0);
}
}
m_entry->setStale(false);
APPLICATION->metacache()->updateEntry(m_entry);