[Python-checkins] cpython: Issue #20480: Add ipaddress.reverse_pointer. Patch by Leon Weber.

[eric.smith]

http://hg.python.org/cpython/rev/5992d2c9522c
changeset:   90270:5992d2c9522c
parent:      90268:ab7f57e92629
user:        Eric V. Smith <eric at trueblade.com>
date:        Mon Apr 14 12:58:07 2014 -0400
summary:
  Issue #20480: Add ipaddress.reverse_pointer. Patch by Leon Weber.

files:
  Doc/library/ipaddress.rst  |  15 +++++++++++++
  Lib/ipaddress.py           |  29 ++++++++++++++++++++++++++
  Lib/test/test_ipaddress.py |   8 +++++++
  Misc/ACKS                  |   1 +
  Misc/NEWS                  |   2 +
  5 files changed, 55 insertions(+), 0 deletions(-)


diff --git a/Doc/library/ipaddress.rst b/Doc/library/ipaddress.rst
--- a/Doc/library/ipaddress.rst
+++ b/Doc/library/ipaddress.rst
@@ -146,6 +146,20 @@
       the appropriate length (most significant octet first). This is 4 bytes
       for IPv4 and 16 bytes for IPv6.
 
+   .. attribute:: reverse_pointer
+
+      The name of the reverse DNS PTR record for the IP address, e.g.::
+
+          >>> ipaddress.ip_address("127.0.0.1").reverse_pointer
+          '1.0.0.127.in-addr.arpa'
+          >>> ipaddress.ip_address("2001:db8::1").reverse_pointer
+          '1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa'
+
+      This is the name that could be used for performing a PTR lookup, not the
+      resolved hostname itself.
+
+   .. versionadded:: 3.5
+
    .. attribute:: is_multicast
 
       ``True`` if the address is reserved for multicast use.  See
@@ -226,6 +240,7 @@
    :class:`IPv4Address` class:
 
    .. attribute:: packed
+   .. attribute:: reverse_pointer
    .. attribute:: version
    .. attribute:: max_prefixlen
    .. attribute:: is_multicast
diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -436,6 +436,17 @@
         return str(self)
 
     @property
+    def reverse_pointer(self):
+        """The name of the reverse DNS pointer for the IP address, e.g.:
+            >>> ipaddress.ip_address("127.0.0.1").reverse_pointer
+            '1.0.0.127.in-addr.arpa'
+            >>> ipaddress.ip_address("2001:db8::1").reverse_pointer
+            '1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa'
+
+        """
+        return self._reverse_pointer()
+
+    @property
     def version(self):
         msg = '%200s has no version specified' % (type(self),)
         raise NotImplementedError(msg)
@@ -1221,6 +1232,15 @@
             return True
         return False
 
+    def _reverse_pointer(self):
+        """Return the reverse DNS pointer name for the IPv4 address.
+
+        This implements the method described in RFC1035 3.5.
+
+        """
+        reverse_octets = str(self).split('.')[::-1]
+        return '.'.join(reverse_octets) + '.in-addr.arpa'
+
     @property
     def max_prefixlen(self):
         return self._max_prefixlen
@@ -1784,6 +1804,15 @@
             return '%s/%d' % (':'.join(parts), self._prefixlen)
         return ':'.join(parts)
 
+    def _reverse_pointer(self):
+        """Return the reverse DNS pointer name for the IPv6 address.
+
+        This implements the method described in RFC3596 2.5.
+
+        """
+        reverse_chars = self.exploded[::-1].replace(':', '')
+        return '.'.join(reverse_chars) + '.ip6.arpa'
+
     @property
     def max_prefixlen(self):
         return self._max_prefixlen
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -1593,6 +1593,14 @@
                          addr3.exploded)
         self.assertEqual('192.168.178.1', addr4.exploded)
 
+    def testReversePointer(self):
+        addr1 = ipaddress.IPv4Address('127.0.0.1')
+        addr2 = ipaddress.IPv6Address('2001:db8::1')
+        self.assertEqual('1.0.0.127.in-addr.arpa', addr1.reverse_pointer)
+        self.assertEqual('1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.' +
+                         'b.d.0.1.0.0.2.ip6.arpa',
+                         addr2.reverse_pointer)
+
     def testIntRepresentation(self):
         self.assertEqual(16909060, int(self.ipv4_address))
         self.assertEqual(42540616829182469433547762482097946625,
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1392,6 +1392,7 @@
 David Watson
 Aaron Watters
 Henrik Weber
+Leon Weber
 Corran Webster
 Glyn Webster
 Phil Webster
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -37,6 +37,8 @@
 - Issue #12546: Allow \x00 to be used as a fill character when using str, int,
   float, and complex __format__ methods.
 
+- Issue #20480: Add ipaddress.reverse_pointer. Patch by Leon Weber.
+
 Library
 -------
 

-- 
Repository URL: http://hg.python.org/cpython