source of a socket error message

Tom Glod tom at makeshyft.com
Wed Jul 17 23:36:24 EDT 2019


That answer is probably bang on

...and a solution to top it off.

* slow clap *

On Wed, Jul 17, 2019 at 9:51 PM Dar Scott via use-livecode <
use-livecode at lists.runrev.com> wrote:

> This is very likely a loss of network availability and of that a loss of
> Internet availability.
>
> The library will first look up the URI to get an IP address. The IP
> address is used to make a connection to the server.  The computer has (or
> can get) an IP address to use for making that look up.  Since that this the
> first operation, a loss of Internet will show up with that error.
>
> If you are sure there is access to the Internet, then it might be that the
> DNS server is down. That seems unlikely, but possible. If the server IP is
> fixed, then use a cached version of the IP. Use hostNameToAddress() to get
> the IP address, save that on success, use the saved address on failure.
>
>
> > On Jul 17, 2019, at 6:27 PM, Douglas Ruisaard via use-livecode <
> use-livecode at lists.runrev.com> wrote:
> >
> > Let me start this off by stating that the information I am seeking IS
> NOT due to an *issue* with LC.  Hopefully, I can make it clear why I am
> asking for assistance from this group in regard to the situation I am
> trying to deal with and why I need the LC expertise of this group as a
> resource.
> >
> > In a portion of a large application, which has been distributed to a
> large number (5,000+) of remote/external sites, I have a call to a TCP
> socket:
> >
> > on OpenCard
> > ...
> >     put ftp_server & ":" & tcp_port into temp1
> >     open socket to temp1 with message "NewConnection"
> >     wait for messages
> > end OpenCard
> >
> > Then there are a variety of "call-backs" based on when happens after I
> open the socket.  One of these call-backs is "socketError":
> >
> > on socketError theID, theError
> >     close socket theID
> >     do_log " " & sftp_account && "file: " & "There is a problem with the
> TCP connection: " & theError, "connect", 3
> >       ...
> > end socketError
> >
> > This works PERFECTLY 99.999% of the time.  However, occasionally I get a
> "mass" of errors (50 or 60) within a 1 hour period of time from a large
> variety of different external sites (I get all of the remote site's logs)
> ... i.e. many different sites connecting in from many different locations
> around the province of Ontario ... a very large place!
> >
> > The error returned is: "can't resolve hostname"... returned in the
> "theError" parameter of the socketError function.
> >
> > Here's where I need help.  I need to find out, with as great a level of
> detail as possible, EXACTLY what (from LC's "point-of-view") triggers this
> error, what part(s) of the LC engine are involved with generating this
> error and if there is more than the obvious cause of the remote site's DNS
> server (via their ISP or internal server(s)) not being able to "see" the
> hostname that could produce this error.
> >
> > Although this "error" appears to be "common" from a variety of sources
> (none of which are written in LC, as far as I can tell)... I cannot find
> any "standard" by  which a DNS generates this specific message.  NSLOOKUP
> would be the closest candidate but even it doesn't produce this specific
> error of being "unable to resolve the hostname"... so that leaves LC with
> the responsibility of the content of the error.
> >
> > I REALLY want to emphasize that, as far as I am concerned, this is not a
> problem with LC, in any manner... but I need to find out where and why LC
> generates this message.
> >
> > I am not sure what or where to search for this error or what generates
> it from with the LC components but if someone could help me "find" a
> starting point, I should be able to reverse-engineer the logic.
> >
> > The overall situation is fairly complex but I'd be very open to
> providing more details if anyone feels it is warranted.
> >
> > Whatever help could be provided will be very, very appreciated!
> >
> > Douglas Ruisaard
> > Trilogy Software
> > (250) 573-3935
> >
> >
> >
> >
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