Passing errors on to ruby on max upload

[Fred]

Hello,
I have a ruby application where users are able to upload a file of max size 1
MB, which alerts users if the file they are trying to upload is over that size.
 In my nginx configuration, I have set the max upload size set to 2 MB as per
client_max_body_size
(http://wiki.codemongers.com/NginxHttpCoreModule#client_max_body_size).

My problem is that when I upload a file that is larger 2 M, nginx gets the error
(as seen in the logs) and nothing is passed to the ruby code, so in the
application it just hangs, waiting to complete the upload.  

So the question is - is there any way to forward the error on to ruby at all or
is there any way to work around this aside from changing the max upload size on
the server (since the absolute max upload size is 10 MB, if they uploaded above
that, I would still have the same behavior).  I have taken a look at the options
for the config files, but I haven't found anything yet.  Any ideas?

Thanks,
Fred