Package dns :: Package rdtypes :: Module txtbase
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Source Code for Module dns.rdtypes.txtbase

 1  # Copyright (C) 2006, 2007, 2009-2011 Nominum, Inc. 
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15   
16  """TXT-like base class.""" 
17   
18  import struct 
19   
20  import dns.exception 
21  import dns.rdata 
22  import dns.tokenizer 
23  from dns._compat import binary_type 
24 25 26 -class TXTBase(dns.rdata.Rdata):
27 28 """Base class for rdata that is like a TXT record 29 30 @ivar strings: the text strings 31 @type strings: list of string 32 @see: RFC 1035""" 33 34 __slots__ = ['strings'] 35
36 - def __init__(self, rdclass, rdtype, strings):
37 super(TXTBase, self).__init__(rdclass, rdtype) 38 if isinstance(strings, str): 39 strings = [strings] 40 self.strings = strings[:]
41
42 - def to_text(self, origin=None, relativize=True, **kw):
43 txt = '' 44 prefix = '' 45 for s in self.strings: 46 txt += '%s"%s"' % (prefix, dns.rdata._escapify(s)) 47 prefix = ' ' 48 return txt
49 50 @classmethod
51 - def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True):
52 strings = [] 53 while 1: 54 token = tok.get().unescape() 55 if token.is_eol_or_eof(): 56 break 57 if not (token.is_quoted_string() or token.is_identifier()): 58 raise dns.exception.SyntaxError("expected a string") 59 if len(token.value) > 255: 60 raise dns.exception.SyntaxError("string too long") 61 value = token.value 62 if isinstance(value, binary_type): 63 strings.append(value) 64 else: 65 strings.append(value.encode()) 66 if len(strings) == 0: 67 raise dns.exception.UnexpectedEnd 68 return cls(rdclass, rdtype, strings)
69
70 - def to_wire(self, file, compress=None, origin=None):
71 for s in self.strings: 72 l = len(s) 73 assert l < 256 74 file.write(struct.pack('!B', l)) 75 file.write(s)
76 77 @classmethod
78 - def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin=None):
79 strings = [] 80 while rdlen > 0: 81 l = wire[current] 82 current += 1 83 rdlen -= 1 84 if l > rdlen: 85 raise dns.exception.FormError 86 s = wire[current: current + l].unwrap() 87 current += l 88 rdlen -= l 89 strings.append(s) 90 return cls(rdclass, rdtype, strings)
91