Source Code for Module dns.ttl

 1  # Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license 
 2   
 3  # Copyright (C) 2003-2017 Nominum, Inc. 
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17   
18  """DNS TTL conversion.""" 
19   
20  import dns.exception 
21  from ._compat import long 
22   
23   
24 -class BadTTL(dns.exception.SyntaxError): 
25      """DNS TTL value is not well-formed.""" 
26   
27   
28 -def from_text(text): 
29      """Convert the text form of a TTL to an integer. 
30   
31      The BIND 8 units syntax for TTLs (e.g. '1w6d4h3m10s') is supported. 
32   
33      *text*, a ``text``, the textual TTL. 
34   
35      Raises ``dns.ttl.BadTTL`` if the TTL is not well-formed. 
36   
37      Returns an ``int``. 
38      """ 
39   
40      if text.isdigit(): 
41          total = long(text) 
42      else: 
43          if not text[0].isdigit(): 
44              raise BadTTL 
45          total = long(0) 
46          current = long(0) 
47          for c in text: 
48              if c.isdigit(): 
49                  current *= 10 
50                  current += long(c) 
51              else: 
52                  c = c.lower() 
53                  if c == 'w': 
54                      total += current * long(604800) 
55                  elif c == 'd': 
56                      total += current * long(86400) 
57                  elif c == 'h': 
58                      total += current * long(3600) 
59                  elif c == 'm': 
60                      total += current * long(60) 
61                  elif c == 's': 
62                      total += current 
63                  else: 
64                      raise BadTTL("unknown unit '%s'" % c) 
65                  current = 0 
66          if not current == 0: 
67              raise BadTTL("trailing integer") 
68      if total < long(0) or total > long(2147483647): 
69          raise BadTTL("TTL should be between 0 and 2^31 - 1 (inclusive)") 
70      return total 
71