Added auto detection of external ip address

TODO

@@ -3,9 +3,6 @@ TODO for dnsupdate
 - Check if address needs update before sending data
 - Add a config-file for hostname, domain and password
   All options should be configurable, ttl and force as well.
-- Auto-detect the machine's external ip address'
-  Should work on OS X, Linux and Windows. 
-  Should work with multiple interfaces.
 - Have options to delete a server as well as add/update
 - Integrate the relevant dnspython modules
 - Add a GUI
@@ -22,3 +19,7 @@ Done:
   -n hostname
   -p password
   -t ttl
+- Auto-detect the machine's external ip address'
+  Should work on OS X, Linux and Windows. 
+  Should work with multiple interfaces.
+  http://www.showmyip.com/simple eller skriva en egen.

dnsupdate.py

@@ -6,7 +6,6 @@ import re
 import string
 import sys
 
-
 # dnsupdate.py
 # Updates a dynamic dns-record using a TSIG key.
 
@@ -15,7 +14,17 @@ keyname = "lubcke.se."
 keysecret = "ZGhNJ05b8ThmHOXhJvkvMw=="
 ttl = 60
 
+def get_ipaddress():
+  # Connects to the dns server to determine which ip address
+  # this host connects from
+  import urllib
+  remote = opener = urllib.FancyURLopener({})
+  f = opener.open("http://www.wahlberg.se/~fredrik/ip.php")
+  ip = f.read().strip()
+  return ip
+
 def main():
+  # Define option parameters
   usage = "usage: %prog [-n] hostname [-i] ip adress [OPTIONS]"
   parser = OptionParser(usage)
   parser.add_option("-d", "--domain", 
@@ -39,10 +48,14 @@ def main():
   (options, args) = parser.parse_args()
   
 
-  global domain, keyname, keysecret, ttl
+  global domain, ipaddress, keyname, keysecret, ttl
 
   if options.domain:
     domain = options.domain
+  if options.ipaddress:
+    ipaddress = options.ipaddress
+  else:
+    ipaddress = get_ipaddress()
   if options.keyname:
     keyname = options.keyname
   if options.password:
@@ -50,18 +63,19 @@ def main():
   if options.ttl:
     ttl = options.ttl
   
-  if not options.ipaddress or not options.name:
-    print "IP address and hostname are required for operation.\nEnter '%s -h' for usage information" % sys.argv[0]
+  if not options.name:
+    print "A hostname is required for operation.\nEnter '%s -h' for usage information" % sys.argv[0]
     return 
   else:
-    global hostname, ipaddress
-    ipaddress = options.ipaddress
+    global hostname
     hostname = options.name
 
   update()
 
 
 def update():
+  # The update function connects to the dns server
+  
   # Sanity check incoming data
   global hostname, ipaddress, ttl
   hostname = string.replace(hostname, "."+domain, '')