Socket timeout not working with libUrl

Frank Leahy frank at backtalk.com
Mon Jan 31 04:11:49 CST 2005


Sarah,

Thanks for the reply.

After a lot of testing on Mac OS X, I've found that the problem I was 
having appears to be due to the way that Mac OS X does DNS lookups.  
Whether or not it's a RunRev bug as well is hard to tell, but I think 
it might be.

Here's some sample code I wrote.  This code sends a "My5SecondTimeout" 
message to itself, opens a socket, makes an HTTP GET request, waits for 
the response, and closes the socket.  (Note: I had to use this 
"My5SecondTimeout" message because setting the socketTimeoutInterval 
doesn't seem to work).

When you run this script and you're not connected to the internet 
here's what happens:

    1) If I open the socket with an ip address, e.g. 64.125.128.80, my 5 
second timer will fire, and I can close the socket and exit from the 
routine.

    2) If I open the socket with a domain address, e.g. 
www.webphotospro.com, Mac OS X does a DNS lookup, puts up the rainbow 
rotating color cursor, and hangs until the DNS lookup fails.  On my 
machine this takes 60 seconds (apparently it's dependent on how many 
dns servers you have listed).

I'm guessing this is a RunRev bug, but I can't be sure.  Basically 
RunRev hangs for 60 seconds while the DNS lookup takes place during the 
"open socket" call -- it doesn't send a socket timeout, and it doesn't 
the "My5SecondTimeout" message either.

Can confirm this?

Thanks,
-- Frank

on mouseUp
   set the socketTimeoutInterval to 5000 -- this seems to do nothing, 
but set it anyway
   global theIp, socketIsOpen, socketTimedOut
   put "www.webphotospro.com:80" into theIp -- using this causes RunRev 
to hang for 60 seconds
   -- put "64.125.128.80:80" into theIp -- using this does not cause a 
hang
   put false into socketIsOpen
   put false into socketTimedOut

   send "My5SecondTimeout" to button "Ping" in 5 seconds -- send a 
message to myself
   close socket theIp -- in case it's currently open
   open socket to theIp with message "mySocketOpenMsg"
   wait until socketIsOpen or socketTimedOut with messages
   if socketTimedOut then
     close socket theIp
     answer "socket timed out"
   end if
end mouseUp

on My5SecondTimeout
   global socketIsOpen, socketTimedOut
   if not socketIsOpen then
     put true into socketTimedOut
   end if
end My5SecondTimeout

on mySocketOpenMsg theParams
   global theIp, socketIsOpen
   put true into socketIsOpen
   write "GET / HTTP/1.0" & numToChar(13) & numToChar(10) & 
numToChar(13) & numToChar(10) to socket theIp
   read from socket theIp for 50 with message "mySocketReadDoneMsg"
end mySocketOpenMsg

on mySocketReadDoneMsg socketId, theData
   global theIp
   close socket theIp
   answer "read done: " & socketId && theData
end mySocketReadDoneMsg

Web Photos Pro: Software for Photo Bloggers and Other Photo Power Users
See us on the web at http://www.webphotospro.com/

On Jan 31, 2005, at 1:16 AM, use-revolution-request at lists.runrev.com 
wrote:

> From: Sarah Reichelt <sarahr at genesearch.com.au>
> Subject: Re: Socket timeout not working with libUrl
> To: How to use Revolution <use-revolution at lists.runrev.com>
> Message-ID: <3A70EDD2-7316-11D9-819B-0003937A97B8 at genesearch.com.au>
> Content-Type: text/plain; charset=US-ASCII; format=flowed
>
>> My product pings the Web Photos Pro website to look for new versions.
>> This works great when the computer the product's running on is
>> connected to the internet, but it hangs for 60 seconds when there's no
>> net connection.
>>
>> My code looks like this:
>>
>>   set the socketTimeoutInterval to 5000
>>   put URL (getPhotoAlbumUrl() & "downloads/version_info.php") into
>> newVersion
>>
>> Is there any way I can force a timeout after 5 seconds?  Should I be
>> using a non-blocking URL request?  Should I be attempting to open a
>> socket directly to do an initial "am I connected to the internet?"
>> request, before making the URL request?
>>
>
> Hi Frank,
>
> I would definitely use a non-blocking request, so the user won't even
> notice if it is trying & failing.
> Try something like:
>    set the socketTimeoutInterval to 5000
>    put (getPhotoAlbumUrl() & "downloads/version_info.php") into tURL
>    load tURL with message gotVersion
>
> Then you need a "gotVersion" handler in the same object:
>
> on gotVersion
>    put URL (getPhotoAlbumUrl() & "downloads/version_info.php") into
> newVersion
>    -- check newVersion & do the usual stuff
> end gotVersion
>
> Hope this helps,
> Sarah



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