Current File : //lib/python3/dist-packages/dns/rdtypes/txtbase.py
# 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."""
from typing import Any, Dict, Iterable, Optional, Tuple, Union
import dns.exception
import dns.immutable
import dns.rdata
import dns.renderer
import dns.tokenizer
@dns.immutable.immutable
class TXTBase(dns.rdata.Rdata):
"""Base class for rdata that is like a TXT record (see RFC 1035)."""
__slots__ = ["strings"]
def __init__(
self,
rdclass: dns.rdataclass.RdataClass,
rdtype: dns.rdatatype.RdataType,
strings: Iterable[Union[bytes, str]],
):
"""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)
self.strings: Tuple[bytes] = self._as_tuple(
strings, lambda x: self._as_bytes(x, True, 255)
)
def to_text(
self,
origin: Optional[dns.name.Name] = None,
relativize: bool = True,
**kw: Dict[str, Any],
) -> str:
txt = ""
prefix = ""
for s in self.strings:
txt += '{}"{}"'.format(prefix, dns.rdata._escapify(s))
prefix = " "
return txt
@classmethod
def from_text(
cls,
rdclass: dns.rdataclass.RdataClass,
rdtype: dns.rdatatype.RdataType,
tok: dns.tokenizer.Tokenizer,
origin: Optional[dns.name.Name] = None,
relativize: bool = True,
relativize_to: Optional[dns.name.Name] = None,
) -> dns.rdata.Rdata:
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:
with dns.renderer.prefixed_length(file, 1):
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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