Source Code for Module dns.ttl

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15   
16  """DNS TTL conversion.""" 
17   
18  import dns.exception 
19  from ._compat import long 
20   
21   
22 -class BadTTL(dns.exception.SyntaxError): 
23   
24      """DNS TTL value is not well-formed.""" 
25   
26   
27 -def from_text(text): 
28      """Convert the text form of a TTL to an integer. 
29   
30      The BIND 8 units syntax for TTLs (e.g. '1w6d4h3m10s') is supported. 
31   
32      @param text: the textual TTL 
33      @type text: string 
34      @raises dns.ttl.BadTTL: the TTL is not well-formed 
35      @rtype: int 
36      """ 
37   
38      if text.isdigit(): 
39          total = long(text) 
40      else: 
41          if not text[0].isdigit(): 
42              raise BadTTL 
43          total = long(0) 
44          current = long(0) 
45          for c in text: 
46              if c.isdigit(): 
47                  current *= 10 
48                  current += long(c) 
49              else: 
50                  c = c.lower() 
51                  if c == 'w': 
52                      total += current * long(604800) 
53                  elif c == 'd': 
54                      total += current * long(86400) 
55                  elif c == 'h': 
56                      total += current * long(3600) 
57                  elif c == 'm': 
58                      total += current * long(60) 
59                  elif c == 's': 
60                      total += current 
61                  else: 
62                      raise BadTTL("unknown unit '%s'" % c) 
63                  current = 0 
64          if not current == 0: 
65              raise BadTTL("trailing integer") 
66      if total < long(0) or total > long(2147483647): 
67          raise BadTTL("TTL should be between 0 and 2^31 - 1 (inclusive)") 
68      return total 
69