testing for Internet connection

[Chipp Walters]

Hi Richard,

I've found this to work well:

function isConnectedToInternet pURL
   if pURL is empty then put "http://www.google.com" into pURL
   get URL pURL
   put the result into tResult
   if tResult is not empty then
     answer information "Problem connecting to the internet: "& tResult
     return false
   else
     return true
   end if
end isConnectedToInternet

a more elaborate variant I use which compensates for long latency 
connections like satellite or some dialups:

function altIsConnected pURL

   --> STORES IN DEBUG FLD IN ALTINTERNET LIBRARY
   altDebug "checking internet connection to:",pURL
   --> TURNS ON ANIMATED BUSY.GIF
   ImBusy true

   put 0 into x
   repeat 5 times
     add 1 to x
     altDebug "Trying to GET from URL:",pURL  && "try " & x
     put URL pURL into pData
     put the result into tResult
     if tResult is not empty then
       answer tResult
       altDebug "Result from GET:",tResult
       exit repeat
     end if
     altDebug "Result from pURL:",pData
     if pData is not empty then
       --> YOU CAN PUT COMMON PROXY AND FIREWALL AUTHENTICATION CODE HERE
       switch
       case "WatchGuard" is in it --WatchGuard firewall
         break
       default
         ImBusy false
         return true
       end switch
     end if
   end repeat
   altDebug "Could not connect to Server after " &x& " tries."
   answer "Cannot connect to: " & pURL &cr& tResult
   ImBusy false
   return false
end altIsConnected

if your user is not connected, they will probably get an 'invalid host'
answer. Testing against google seems always to work for me. I figure, if
they can't get to google, then they can't get to my server.

-Chipp

Richard Gaskin wrote:
> There have been many posts here over the last couple years about
> various methods of having an app test to see if it has an Internet
> connection available, but for every suggestion I can find in the
> archives there's a subsequent post explaining why that method isn't
> optimal or in some cases even reliable.