lib/dnspython/dns/e164.py

   1 # Copyright (C) 2006, 2007, 2009, 2011 Nominum, Inc.
   2 #
   3 # Permission to use, copy, modify, and distribute this software and its
   4 # documentation for any purpose with or without fee is hereby granted,
   5 # provided that the above copyright notice and this permission notice
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   9 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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  13 # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  14 # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15
  16 """DNS E.164 helpers
  17
  18 @var public_enum_domain: The DNS public ENUM domain, e164.arpa.
  19 @type public_enum_domain: dns.name.Name object
  20 """
  21
  22 import dns.exception
  23 import dns.name
  24 import dns.resolver
  25
  26 public_enum_domain = dns.name.from_text('e164.arpa.')
  27
  28 def from_e164(text, origin=public_enum_domain):
  29     """Convert an E.164 number in textual form into a Name object whose
  30     value is the ENUM domain name for that number.
  31     @param text: an E.164 number in textual form.
  32     @type text: str
  33     @param origin: The domain in which the number should be constructed.
  34     The default is e164.arpa.
  35     @type: dns.name.Name object or None
  36     @rtype: dns.name.Name object
  37     """
  38     parts = [d for d in text if d.isdigit()]
  39     parts.reverse()
  40     return dns.name.from_text('.'.join(parts), origin=origin)
  41
  42 def to_e164(name, origin=public_enum_domain, want_plus_prefix=True):
  43     """Convert an ENUM domain name into an E.164 number.
  44     @param name: the ENUM domain name.
  45     @type name: dns.name.Name object.
  46     @param origin: A domain containing the ENUM domain name.  The
  47     name is relativized to this domain before being converted to text.
  48     @type: dns.name.Name object or None
  49     @param want_plus_prefix: if True, add a '+' to the beginning of the
  50     returned number.
  51     @rtype: str
  52     """
  53     if not origin is None:
  54         name = name.relativize(origin)
  55     dlabels = [d for d in name.labels if (d.isdigit() and len(d) == 1)]
  56     if len(dlabels) != len(name.labels):
  57         raise dns.exception.SyntaxError('non-digit labels in ENUM domain name')
  58     dlabels.reverse()
  59     text = ''.join(dlabels)
  60     if want_plus_prefix:
  61         text = '+' + text
  62     return text
  63
  64 def query(number, domains, resolver=None):
  65     """Look for NAPTR RRs for the specified number in the specified domains.
  66
  67     e.g. lookup('16505551212', ['e164.dnspython.org.', 'e164.arpa.'])
  68     """
  69     if resolver is None:
  70         resolver = dns.resolver.get_default_resolver()
  71     for domain in domains:
  72         if isinstance(domain, (str, unicode)):
  73             domain = dns.name.from_text(domain)
  74         qname = dns.e164.from_e164(number, domain)
  75         try:
  76             return resolver.query(qname, 'NAPTR')
  77         except dns.resolver.NXDOMAIN:
  78             pass
  79     raise dns.resolver.NXDOMAIN