any way to detect condition "connected to ISP but not internet"?

[Alex Tweedly]

Andre Garzia wrote:
> we can use the load command in async mode and check the status... it
> should timeout right?
>
>   
right. maybe.

(remember there's a lot of speculation on my part, about this being a 
DNS problem ....)

Although the load url ... with callback is intended to be non-blocking, 
there may be a difficulty. I'm sure it uses sockets and the socket async 
mode to be non-blocking - and I suspect the problem is an OS call to 
DNSresolve() [or similar] which is happens before the scket/TCP open, 
and which is blocking. Since this affects (even) a browser, I worry it 
would also affect Rev - so it might just result in a blocked process. 
(and even if it's not DNS, whatever it is fails within a browser, so may 
fail similarly within Rev)

To feel safe, I'd want to do the network check in a separate process, 
and have a fail-safe mechanism within the real app (i.e. it detects 
failure rather than waiting for it). So I'd use a backgrounded shell 
command which creates a temp file, and have the real app check for that 
file being created/updated. Could be a ping shell command, or a small 
standalone which loads a url, or anything similar - as long as it's a 
separate process.

-- Alex.