Checking Internet connection on Vista

[Eric Chatonet]

Bonjour LAex,

LOL a bit...
You are right...

Finally I ended with something close to your proposal:

function InternetConnected
   local tAddress,tResult
   -----
   put line 1 of hostNameToAddress(the uTestUrl of stack "VTCommon")  
into tAddress
   if tAddress = empty then return false
   set hideconsolewindows to true
   put shell(quote & "ping -n 1 -w 1000" && tAddress & quote) into  
tResult
   set hideconsolewindows to false
   return the number of lines of tResult > 10
end InternetConnected

It's for Windows, of course.
As it sets a timeout, it seems not too bad even if it is not the best...
In addition, it takes into account buffering you were talking about  
and, yes, it can be a problem.

Le 21 juin 08 à 01:36, Alex Tweedly a écrit :

> Eric Chatonet wrote:
>> Bernard,
>>
>> Of course I can't send a GET request (or a LOAD): the software (I  
>> cross my fingers :-) will be used by hundred thousands of persons  
>> (I hope more :-)...
>
> I'm not at all convinced that would be a problem. Every copy of  
> Vista has the browser set to use the same default home page  
> (probably msn.com); every download of Firefox is set to use the  
> same home page - so there are millions of users doing a get on one  
> of 3 or 4 highly popular pages every time they start their browser.  
> "hundreds of thousands" of your users checking once per time they  
> run your app is insignificant.
>
> Once you ship more copies than Firefox you can start to worry :-)
>
> However, there is a more serious problem than that ....
>
> anything (HostNametoAddress, or openSocket, or ..) that uses a host  
> name will try to do a DNS lookup on the host. So you are almost  
> guaranteed that when the Internet connection is down, there can be  
> a variable, but multi-second long, delay. Even worse, there is a  
> distinct possibility that you will get a "false positive" result  
> from HostNametoAddress due to DNS caching - any responsible host/ 
> domain will give a reasonably long DNS cache period, so if anyone  
> on your local network has recently connected to the chosen host,  
> its IP address will be cached on the Netgear (or equivalent), and  
> therefore it can respond with an IP address without using, or  
> checking, the Internet connection.
>
>
>> I'll try what I can get from a simple openSocket but I guess that  
>> HostNametoAddress built-in function uses it.
>> That's the problem...
>>
>
> I'd suggest storing some numeric IP addresses, and doing something  
> like
>   shell("ping " & tIPAddr)
> and checking the output for success. You could equally do a get or  
> load on the numeric IP Address.
>
> You could periodically (even every time the app is run - but not in  
> a user-visible delay path) do a shell ("nslookup" && tHostName) to  
> refresh your list of IP addresss.
>
>> Le 20 juin 08 à 18:07, Bernard Devlin a écrit :
>>
>>> Maybe the most reliable time-critical way to check would be to  
>>> open your own
>>> socket on port 80 to something like www.google.com.  By setting the
>>> SocketTimeoutInterval to a low value you would find out quickly  
>>> if the
>>> timeout occured without a response.  I'm thinking that you would  
>>> not even
>>> send a GET request, just see if the socket could be opened.
>>>
>>> bernard
>>>
>>> On Fri, Jun 20, 2008 at 4:52 PM, Eric Chatonet <
>>> eric.chatonet at sosmartsoftware.com> wrote:
>>>
>>>> Thanks for testing at your place: it's invaluable :-)
>>>> Tests I made were with the router connected but the ADSL modem  
>>>> disconnected
>>>> and I'm afraid it is the delay reason.
>>>>
>>>> Le 20 juin 08 à 17:45, Bernard Devlin a écrit :
>>>>
>>>>
>>>>  I done some further tests, and mostly I'm getting a result with  
>>>> the router
>>>>> disconnected of less than 30ms now.  I can't reproduce the case  
>>>>> where I
>>>>> got
>>>>> 14 seconds.  I had a look at socketTimeoutInterval and it  
>>>>> seemed to make
>>>>> no
>>>>> difference at all.  Still, if you are getting lengthy delays  
>>>>> then it looks
>>>>> like this is not an adequate way to get a speedy test to see if  
>>>>> the
>>>>> internet
>>>>> connection is still alive.
>>>>>
>>>>> Bernard
>>>>>
>>>>> On Fri, Jun 20, 2008 at 3:53 PM, Eric Chatonet <
>>>>> eric.chatonet at sosmartsoftware.com> wrote:
>>>>>
>>>>>  Your allusion about SocketTimeoutInterval seems to be very  
>>>>> well thought
>>>>>> :-)
>>>>>> The problem is that I (the user) can't accept more than a 200  
>>>>>> ms hang and
>>>>>> this could be not enough when he is regularly connected.
>>>>>> So this fails to address the problem :-(
>>
>> _______________________________________________
>> use-revolution mailing list
>> use-revolution at lists.runrev.com
>> Please visit this url to subscribe, unsubscribe and manage your  
>> subscription preferences:
>> http://lists.runrev.com/mailman/listinfo/use-revolution
>>
>
> _______________________________________________
> use-revolution mailing list
> use-revolution at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your  
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-revolution
>