Handle network timeouts

[tomasMizera]

Input does not handle network timeouts, our Qt version does not yet provide such option so we should either:

a) set timer when sending request and if we do not get response until timer is triggered, we should consider this as a timeout, or

b) update version to 5.15, there should be mechanism to handle timeouts https://codereview.qt-project.org/c/qt/qtbase/+/278064
https://forum.qt.io/topic/19182/handling-network-timeout-in-qt/4

[saberraz]

+1 to upgrade to 5.15!

[wonder-sk]

Hmm we should be using QgsNetworkAccessManager which is a subclass of QNetworkAccessManager which adds also timeout handling - which is configurable in QGIS and defaults to 60 seconds...

[tomasMizera]

@wonder-sk thanks, I looked at the code, however could not find any reference to QgsNetworkAccessManager in app (only QNetworkAccessManager) neither see log messages about request being canceled after 60 seconds. However, this could be a third option c) how to solve it - use QgsNetworkAccessManager!

Also found this: https://doc.qt.io/qt-5/qnetworkaccessmanager.html#setTransferTimeout but it is indeed from Qt 5.15

[wonder-sk]

Thinking about this again... now that we also support a standalone "mergin" executable that does not use QGIS libs, probably best to stick to QNetworkAccessManager and just use the approach with QTimer... or use Qt 5.15 :-)