"Wrap" a python-cgi

[Kalle Svensson]

Sez Hermann Himmelbauer:
> Hi,
> I am currently using python for several cgi programs. One problem is that 
> if my cgi-script has a bug it exits with an exception and the user gets an 
> ugly error message done by the webserver.
> 
> I would like to put some really simple "bugfree" (if something like this 
> can exist :-) "wrapper" around my cgi-scripts, let it trap Exceptions, log 
> the error and let it output a nice error page to the user.
> 
> My first approach would perhaps be to wrap the whole script into a "try: 
> except" clause but at first I don't know if nested try/except clauses are 
> allowed and moreover the whole script looks somehow ugly as every line is 
> indented.

This is basically a good idea, but you should use functions too.  Something
like this might work (untested):

def main():
    # whatever goes here...

if __name__ == "__main__":
    print "Content-Type: text/html\n"
    try:
        main()
    except:
        import traceback, sys
	print "<h1>Error!</h1>\n<pre>"
	traceback.print_exc(file=sys.stdout)
	print "</pre>"

And yes, try: ... except: blocks can be nested.

Peace,
  Kalle
-- 
Email: kalle at gnupung.net     | You can tune a filesystem, but you
Web: http://www.gnupung.net/ | can't tune a fish. -- man tunefs(8)
PGP fingerprint: 0C56 B171 8159 327F 1824 F5DE 74D7 80D7 BF3B B1DD
[Not signed due to braindamage.  Blame Microsoft Outlook Express.]