Updating our desktop app to use Xojo 2019 r1 has had an unexpected side effect: images that use an http:// URL no longer load in an HTML viewer on macOS.
Replicating the problem has been a bit tricky, because there seems to be some cacheing going on. As far as I can tell, if a Mac has ever successfully loaded that URL into an HTML viewer then the image will display correctly (e.g. by using a version of Xojo prior to the switch to using the macOS 10.14 SDK, or by using the Info.plist workaround that I'm about to describe). Otherwise, we see the missing image icon.
I'm guessing that this is happening because changing the macOS SDK means that App Transport Security is now being applied to my app.
We can disable App Transport Security by including the following key in our Info.plist file, and that fixes the problem:
<key>NSAppTransportSecurity</key> <dict> <!-- Include to allow all connections; avoid if possible --> <key>NSAllowsArbitraryLoads</key> <true/> </dict>
Are there any downsides to doing this? Does it trigger any security warnings, require further entitlements, etc?