| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128 |
- # Copyright (C) 2003-2007, 2009-2011 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.
- """Common DNS Exceptions."""
- class DNSException(Exception):
- """Abstract base class shared by all dnspython exceptions.
- It supports two basic modes of operation:
- a) Old/compatible mode is used if __init__ was called with
- empty **kwargs.
- In compatible mode all *args are passed to standard Python Exception class
- as before and all *args are printed by standard __str__ implementation.
- Class variable msg (or doc string if msg is None) is returned from str()
- if *args is empty.
- b) New/parametrized mode is used if __init__ was called with
- non-empty **kwargs.
- In the new mode *args has to be empty and all kwargs has to exactly match
- set in class variable self.supp_kwargs. All kwargs are stored inside
- self.kwargs and used in new __str__ implementation to construct
- formatted message based on self.fmt string.
- In the simplest case it is enough to override supp_kwargs and fmt
- class variables to get nice parametrized messages.
- """
- msg = None # non-parametrized message
- supp_kwargs = set() # accepted parameters for _fmt_kwargs (sanity check)
- fmt = None # message parametrized with results from _fmt_kwargs
- def __init__(self, *args, **kwargs):
- self._check_params(*args, **kwargs)
- if kwargs:
- self.kwargs = self._check_kwargs(**kwargs)
- self.msg = str(self)
- else:
- self.kwargs = dict() # defined but empty for old mode exceptions
- if self.msg is None:
- # doc string is better implicit message than empty string
- self.msg = self.__doc__
- if args:
- super(DNSException, self).__init__(*args)
- else:
- super(DNSException, self).__init__(self.msg)
- def _check_params(self, *args, **kwargs):
- """Old exceptions supported only args and not kwargs.
- For sanity we do not allow to mix old and new behavior."""
- if args or kwargs:
- assert bool(args) != bool(kwargs), \
- 'keyword arguments are mutually exclusive with positional args'
- def _check_kwargs(self, **kwargs):
- if kwargs:
- assert set(kwargs.keys()) == self.supp_kwargs, \
- 'following set of keyword args is required: %s' % (
- self.supp_kwargs)
- return kwargs
- def _fmt_kwargs(self, **kwargs):
- """Format kwargs before printing them.
- Resulting dictionary has to have keys necessary for str.format call
- on fmt class variable.
- """
- fmtargs = {}
- for kw, data in kwargs.items():
- if isinstance(data, (list, set)):
- # convert list of <someobj> to list of str(<someobj>)
- fmtargs[kw] = list(map(str, data))
- if len(fmtargs[kw]) == 1:
- # remove list brackets [] from single-item lists
- fmtargs[kw] = fmtargs[kw].pop()
- else:
- fmtargs[kw] = data
- return fmtargs
- def __str__(self):
- if self.kwargs and self.fmt:
- # provide custom message constructed from keyword arguments
- fmtargs = self._fmt_kwargs(**self.kwargs)
- return self.fmt.format(**fmtargs)
- else:
- # print *args directly in the same way as old DNSException
- return super(DNSException, self).__str__()
- class FormError(DNSException):
- """DNS message is malformed."""
- class SyntaxError(DNSException):
- """Text input is malformed."""
- class UnexpectedEnd(SyntaxError):
- """Text input ended unexpectedly."""
- class TooBig(DNSException):
- """The DNS message is too big."""
- class Timeout(DNSException):
- """The DNS operation timed out."""
- supp_kwargs = set(['timeout'])
- fmt = "The DNS operation timed out after {timeout} seconds"
|