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# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2006-2017 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""TXT-like base class."""
import struct
import dns.exception
import dns.rdata
import dns.tokenizer
class TXTBase(dns.rdata.Rdata):
"""Base class for rdata that is like a TXT record (see RFC 1035)."""
__slots__ = ['strings']
def __init__(self, rdclass, rdtype, strings):
"""Initialize a TXT-like rdata.
*rdclass*, an ``int`` is the rdataclass of the Rdata.
*rdtype*, an ``int`` is the rdatatype of the Rdata.
*strings*, a tuple of ``bytes``
"""
super().__init__(rdclass, rdtype)
if isinstance(strings, (bytes, str)):
strings = (strings,)
encoded_strings = []
for string in strings:
if isinstance(string, str):
string = string.encode()
else:
string = dns.rdata._constify(string)
encoded_strings.append(string)
object.__setattr__(self, 'strings', tuple(encoded_strings))
def to_text(self, origin=None, relativize=True, **kw):
txt = ''
prefix = ''
for s in self.strings:
txt += '{}"{}"'.format(prefix, dns.rdata._escapify(s))
prefix = ' '
return txt
@classmethod
def from_text(cls, rdclass, rdtype, tok, origin=None, relativize=True,
relativize_to=None):
strings = []
for token in tok.get_remaining():
token = token.unescape_to_bytes()
# The 'if' below is always true in the current code, but we
# are leaving this check in in case things change some day.
if not (token.is_quoted_string() or
token.is_identifier()): # pragma: no cover
raise dns.exception.SyntaxError("expected a string")
if len(token.value) > 255:
raise dns.exception.SyntaxError("string too long")
strings.append(token.value)
if len(strings) == 0:
raise dns.exception.UnexpectedEnd
return cls(rdclass, rdtype, strings)
def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
for s in self.strings:
l = len(s)
assert l < 256
file.write(struct.pack('!B', l))
file.write(s)
@classmethod
def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
strings = []
while parser.remaining() > 0:
s = parser.get_counted_bytes()
strings.append(s)
return cls(rdclass, rdtype, strings)
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