Updating files that may be in use?

External Since: May 18, 2004 Posts: 2

Hi all,

Im generating and overwriting, each second, an XML file on the webserver
using a Win32 process. This file will be used by many (>20) clients, each
getting a new copy of the file every second or so.

Im thinking that therell be scope for file in use errors, since I wouldnt be
able to update files that are at that moment being accessed by the webserver
to be sent to a client application. As a simple test, with the XML
generating process running each second, refreshing a browser window manually
causes this error to occur quite often. Im guessing that it would be even
more likely with 20 clients doing the same.

Im sure that this is a common problem - But is there a standard solution to
get around it? One idea Ive had is to not write the XML unless the file is
not in use, or until all reads have ended, but I feel that that may make
dirty XML pages available longer than they could be. Another idea is to set
up an ASP page to publish the latest XML file (which have all been
timestamped). This should work but may be an unecessary load on the server
both in terms of generating the XML each access, and the storage of a new
XML file each second.

So...how?

Thanks!

Spammy

External Since: Aug 23, 2003 Posts: 2972

I would probably use a Web Service. (based on nothing more than what you
have written, so it might not be suitable, but you could consider to use
one)

Anyway, what you need is something between the storage (the xml file), and
the client, taking care of all the "problems" (file in use and such). What
you implement depend on what suits you best.

--
Regards,
Kristofer Gafvert - IIS MVP
<a style='text-decoration: underline;' href="http://www.ilopia.com" target="_blank">http://www.ilopia.com</a> - When you need help!

"spammy" <me.TakeThisOut@privacy.net> wrote in message
news:2guqbhF74173U1@uni-berlin.de...
> Hi all,
>
> Im generating and overwriting, each second, an XML file on the webserver
> using a Win32 process. This file will be used by many (>20) clients, each
> getting a new copy of the file every second or so.
>
> Im thinking that therell be scope for file in use errors, since I wouldnt
be
> able to update files that are at that moment being accessed by the
webserver
> to be sent to a client application. As a simple test, with the XML
> generating process running each second, refreshing a browser window
manually
> causes this error to occur quite often. Im guessing that it would be even
> more likely with 20 clients doing the same.
>
> Im sure that this is a common problem - But is there a standard solution
to
> get around it? One idea Ive had is to not write the XML unless the file is
> not in use, or until all reads have ended, but I feel that that may make
> dirty XML pages available longer than they could be. Another idea is to
set
> up an ASP page to publish the latest XML file (which have all been
> timestamped). This should work but may be an unecessary load on the server
> both in terms of generating the XML each access, and the storage of a new
> XML file each second.
>
> So...how?
>
> Thanks!
>
> Spammy
>
>
>
>