What is the best language for starting an image? I have two programs 
here: one in perl [1]; and, the other in python [2]. The perl works. The 
python does not. Both are attempts to write an "external rewriting 
program" for Apache [3]

The aim of the program is to isolate a subdomain from a request; use it 
to return a port number from a list of subdomains; check to see if the 
port is open with netcat; if closed, start an image on the port number 
and then print the port number; if open, print the port number. Both 
programs turn off buffering.

I have no idea what type lives in $_ and I don't seem to have to care. 
With the python, whatever type readline() is putting into the variable 
input, I can neither concatenate nor format with another string. Every 
step produces some wrinkle I do not see.

I finally fed input into netcat by adding '\r'. The reason the input 
variable cannot be formatted into a string and then fed to Popen defies 
me utterly.

What's going on? I mean, I could use the perl program, but sort of want 
to invest in python.

Chris

[1]

#!/usr/bin/perl -w
# ERP - External Rewrite Program
# take a subdomain and return a port number

$| = 1;

while(<STDIN>) {

$answer=`nc -z localhost $_`;

if ($answer eq '') {

     $path = sprintf("/home/ooplatin/coglinux/lib/squeak/4.0-2585/squeak 
-vm display=none /home/ooplatin/squeak.org/Squeak4.4alpha.image 
/home/ooplating/dirfarm/%u/startparameters.st&", $_);

     system($path);

     sleep(3);

     print $_;

} else {

     print $_;
}

}

[2]

#!/usr/bin/env python
# ERP - External Rewrite Program
# take a subdomain and return a port number

import sys, commands, time, subprocess

while True:

     input = sys.stdin.readline()
     ncstring = '/usr/bin/nc -z localhost ' + input + '\r'
     myoutput = commands.getoutput(ncstring)

     if len(myoutput) < 40:
         startstring = 
"/home/ooplatin/coglinux/lib/squeak/4.0-2585/squeak -vm display-none 
/home/ooplatin/squeak.org/Squeak4.4alpha.image 
/home/ooplatin/dirfarm/%s/startparams.st&" % (input)
         subprocess.Popen(startstring, shell=True, stdout=subprocess.PIPE)
         time.sleep(3)
         print input
     else:
         print input



[3]

     ServerName www.ooplatin.com
     ServerAlias *.ooplatin.com
     DocumentRoot /home/ooplatin
     RewriteLog /etc/httpd/logs/rewrite_log
     RewriteLogLevel 9
     RewriteEngine On
     TransferLog /home/ooplatin/access_log
     ErrorLog /home/ooplatin/error_log
     RewriteMap ERP prg:/home/ooplatin/ERP.py
     RewriteMap SUBDOMAINS txt:/home/ooplatin/subdomains
     RewriteCond %{HTTP_HOST} ^([^.]+)\.ooplatin.com
     RewriteRule ^(.*) http://%1.ooplatin.com:${ERP:${SUBDOMAINS:%1}} [P]