new check_ip() validates if a str is a ip addr and also determines address family, deduplicate code

nsupdate/api/views.py

@@ -5,8 +5,6 @@ import os
 import logging
 logger = logging.getLogger(__name__)
 
-import dns.inet
-
 from django.http import HttpResponse
 from django.conf import settings
 from django.contrib.auth.hashers import check_password
@@ -14,7 +12,7 @@ from django.contrib.auth.decorators import login_required
 from django.contrib.sessions.backends.db import SessionStore
 
 from main.models import Host
-from main.dnstools import update, SameIpError
+from main.dnstools import update, SameIpError, check_ip
 
 
 def Response(content):
@@ -51,8 +49,7 @@ def DetectIpView(request, secret=None):
     # the secret:
     s = SessionStore(session_key=secret)
     ipaddr = request.META['REMOTE_ADDR']
-    af = dns.inet.af_for_address(ipaddr)
-    key = 'ipv4' if af == dns.inet.AF_INET else 'ipv6'
+    key = check_ip(ipaddr)
     s[key] = ipaddr
     s.save()
     with open(os.path.join(settings.STATIC_ROOT, "1px.gif"), "rb") as f:

nsupdate/main/dnstools.py

@@ -22,15 +22,19 @@ class SameIpError(ValueError):
     """
 
 
-def get_rdtype(ipaddr):
+def check_ip(ipaddr, keys=('ipv4', 'ipv6')):
     """
-    Get the record type 'A' or 'AAAA' for this ipaddr.
+    Check if a string is a valid ip address and also
+    determine the kind of the address (address family).
+    Return first key for v4, second key for v6.
 
-    :param ipaddr: ip address v4 or v6 (str)
-    :return: 'A' or 'AAAA'
+    :param ipaddr: ip address, v4 or v6, str
+    :param keys: 2-tuple (v4key, v6key)
+    :return: v4key or v6key
+    :raises: ValueError if the ip is invalid
     """
     af = dns.inet.af_for_address(ipaddr)
-    return 'A' if af == dns.inet.AF_INET else 'AAAA'
+    return keys[af == dns.inet.AF_INET6]
 
 
 def add(fqdn, ipaddr, ttl=60):
@@ -44,7 +48,7 @@ def add(fqdn, ipaddr, ttl=60):
     :param ttl: time to live, default 60s (int)
     :raises: SameIpError if new and old IP is the same
     """
-    rdtype = get_rdtype(ipaddr)
+    rdtype = check_ip(ipaddr, keys=('A', 'AAAA'))
     try:
         current_ipaddr = query_ns(fqdn, rdtype)
         # check if ip really changed
@@ -89,7 +93,7 @@ def update(fqdn, ipaddr, ttl=60):
     :param ttl: time to live, default 60s (int)
     :raises: SameIpError if new and old IP is the same
     """
-    rdtype = get_rdtype(ipaddr)
+    rdtype = check_ip(ipaddr, keys=('A', 'AAAA'))
     try:
         current_ipaddr = query_ns(fqdn, rdtype)
         # check if ip really changed

nsupdate/main/views.py

@@ -57,10 +57,9 @@ class HomeView(TemplateView):
         context = super(HomeView, self).get_context_data(*args, **kwargs)
         context['nav_home'] = True
 
-        s = self.request.session
         ipaddr = self.request.META['REMOTE_ADDR']
-        af = dns.inet.af_for_address(ipaddr)
-        key = 'ipv4' if af == dns.inet.AF_INET else 'ipv6'
+        key = dnstools.check_ip(ipaddr)
+        s = self.request.session
         s[key] = ipaddr
         s.save()