designate/designate/objects/rrdata_txt.py

108 lines
3.8 KiB
Python

# Copyright (c) 2014 Rackspace Hosting
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from designate.objects import base
from designate.objects import fields
from designate.objects.record import Record
from designate.objects.record import RecordList
@base.DesignateRegistry.register
class TXT(Record):
"""
TXT Resource Record Type
Defined in: RFC1035
"""
fields = {
'txt_data': fields.TxtField()
}
@staticmethod
def _is_wrapped_in_double_quotes(value):
return value.startswith('"') and value.endswith('"')
@staticmethod
def _is_missing_double_quote(value):
return ((value.startswith('"') and not value.endswith('"')) or
(not value.startswith('"') and value.endswith('"')))
def _validate_record_single_string(self, value):
if len(value) > 255:
raise ValueError(
'Any TXT record string exceeding 255 characters has to be '
'split.'
)
if self._is_missing_double_quote(value):
raise ValueError(
'TXT record is missing a double quote either at beginning '
'or at end.'
)
if not self._is_wrapped_in_double_quotes(value):
# value with spaces should be quoted as per RFC1035 5.1
for element in value:
if element.isspace():
raise ValueError(
'Empty spaces are not allowed in TXT record, '
'unless wrapped in double quotes.'
)
else:
# quotes within value should be escaped with backslash
strip_value = value.strip('"')
for index, char in enumerate(strip_value):
if char == '"':
if strip_value[index - 1] != "\\":
raise ValueError(
'Quotation marks should be escaped with backslash.'
)
def from_string(self, value):
if len(value) > 255:
# expecting record containing multiple strings as
# per rfc7208 3.3 and rfc1035 3.3.14
stripped_value = value.strip('"')
if (not self._is_wrapped_in_double_quotes(value) and
'" "' not in stripped_value):
raise ValueError(
'TXT record strings over 255 characters have to be split '
'into multiple strings wrapped in double quotes.'
)
record_strings = stripped_value.split('" "')
for record_string in record_strings:
# add back the delimiting quotes after
# strip and split for each string
record_string = f'"{record_string}"'
# further validate each string individually
self._validate_record_single_string(value=record_string)
else:
# validate single TXT record string
self._validate_record_single_string(value=value)
self.txt_data = value
# The record type is defined in the RFC. This will be used when the record
# is sent by mini-dns.
RECORD_TYPE = 16
@base.DesignateRegistry.register
class TXTList(RecordList):
LIST_ITEM_TYPE = TXT
fields = {
'objects': fields.ListOfObjectsField('TXT'),
}