At In-Touch, we often have to use cell cards to get internet to our on-site events. When operating in the United States, we use Sprint Mobile Broadband. For years, it was a great service that had saved the company a lot of time, effort and money.
… until recently …
At a recent event, we started having some problems. We didn’t immediately connect it to Sprint, as the problem only arose
when we took the apps offline (removed the cell cards from the units) and were relying on running from the appCache. The
problem we started seeing was, when resetting a unit, the application would freeze in the browser with the status text
Waiting on 220.127.116.11 ... Hmm,
18.104.22.168? That’s a very strange address. A quick grep of the source shows nobody
managed to slip a typo in there, nothing at all references
22.214.171.124, so where’s that coming from?
Ok, view source …
1 2 3
Where did that come from? The very first line after
<html>, that’s definitely not in the application source.
So not only does their injection not work with the HTML5 appCache, causing offline apps to fail outright – but they just plainly inject bugs by indiscriminately stripping whitespace from source files.
So it turns out, through some Googling and testing, that ByteMobile actually respects the
no-transform. So using the Apache Header module, we have added the following line to our application virtual host
no-transform into any existing
Cache-Control header, allowing apps to still add their own
directives but making sure
no-transform is always there.
After some more research, it turns out AT&T, Vodafone and Orange also use the same software – so take care if using their mobile broadband services, too!