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lib/python3.6/site-packages/dns/message.py 0000644 00000124171 15051567662 0014407 0 ustar 00 # Copyright (C) 2001-2007, 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.
"""DNS Messages"""
from __future__ import absolute_import
from io import StringIO
import struct
import time
import dns.edns
import dns.exception
import dns.flags
import dns.name
import dns.opcode
import dns.entropy
import dns.rcode
import dns.rdata
import dns.rdataclass
import dns.rdatatype
import dns.rrset
import dns.renderer
import dns.tsig
import dns.wiredata
from ._compat import long, xrange, string_types
class ShortHeader(dns.exception.FormError):
"""The DNS packet passed to from_wire() is too short."""
class TrailingJunk(dns.exception.FormError):
"""The DNS packet passed to from_wire() has extra junk at the end of it."""
class UnknownHeaderField(dns.exception.DNSException):
"""The header field name was not recognized when converting from text
into a message."""
class BadEDNS(dns.exception.FormError):
"""OPT record occurred somewhere other than the start of
the additional data section."""
class BadTSIG(dns.exception.FormError):
"""A TSIG record occurred somewhere other than the end of
the additional data section."""
class UnknownTSIGKey(dns.exception.DNSException):
"""A TSIG with an unknown key was received."""
class Message(object):
"""A DNS message.
@ivar id: The query id; the default is a randomly chosen id.
@type id: int
@ivar flags: The DNS flags of the message. @see: RFC 1035 for an
explanation of these flags.
@type flags: int
@ivar question: The question section.
@type question: list of dns.rrset.RRset objects
@ivar answer: The answer section.
@type answer: list of dns.rrset.RRset objects
@ivar authority: The authority section.
@type authority: list of dns.rrset.RRset objects
@ivar additional: The additional data section.
@type additional: list of dns.rrset.RRset objects
@ivar edns: The EDNS level to use. The default is -1, no Edns.
@type edns: int
@ivar ednsflags: The EDNS flags
@type ednsflags: long
@ivar payload: The EDNS payload size. The default is 0.
@type payload: int
@ivar options: The EDNS options
@type options: list of dns.edns.Option objects
@ivar request_payload: The associated request's EDNS payload size.
@type request_payload: int
@ivar keyring: The TSIG keyring to use. The default is None.
@type keyring: dict
@ivar keyname: The TSIG keyname to use. The default is None.
@type keyname: dns.name.Name object
@ivar keyalgorithm: The TSIG algorithm to use; defaults to
dns.tsig.default_algorithm. Constants for TSIG algorithms are defined
in dns.tsig, and the currently implemented algorithms are
HMAC_MD5, HMAC_SHA1, HMAC_SHA224, HMAC_SHA256, HMAC_SHA384, and
HMAC_SHA512.
@type keyalgorithm: string
@ivar request_mac: The TSIG MAC of the request message associated with
this message; used when validating TSIG signatures. @see: RFC 2845 for
more information on TSIG fields.
@type request_mac: string
@ivar fudge: TSIG time fudge; default is 300 seconds.
@type fudge: int
@ivar original_id: TSIG original id; defaults to the message's id
@type original_id: int
@ivar tsig_error: TSIG error code; default is 0.
@type tsig_error: int
@ivar other_data: TSIG other data.
@type other_data: string
@ivar mac: The TSIG MAC for this message.
@type mac: string
@ivar xfr: Is the message being used to contain the results of a DNS
zone transfer? The default is False.
@type xfr: bool
@ivar origin: The origin of the zone in messages which are used for
zone transfers or for DNS dynamic updates. The default is None.
@type origin: dns.name.Name object
@ivar tsig_ctx: The TSIG signature context associated with this
message. The default is None.
@type tsig_ctx: hmac.HMAC object
@ivar had_tsig: Did the message decoded from wire format have a TSIG
signature?
@type had_tsig: bool
@ivar multi: Is this message part of a multi-message sequence? The
default is false. This variable is used when validating TSIG signatures
on messages which are part of a zone transfer.
@type multi: bool
@ivar first: Is this message standalone, or the first of a multi
message sequence? This variable is used when validating TSIG signatures
on messages which are part of a zone transfer.
@type first: bool
@ivar index: An index of rrsets in the message. The index key is
(section, name, rdclass, rdtype, covers, deleting). Indexing can be
disabled by setting the index to None.
@type index: dict
"""
def __init__(self, id=None):
if id is None:
self.id = dns.entropy.random_16()
else:
self.id = id
self.flags = 0
self.question = []
self.answer = []
self.authority = []
self.additional = []
self.edns = -1
self.ednsflags = 0
self.payload = 0
self.options = []
self.request_payload = 0
self.keyring = None
self.keyname = None
self.keyalgorithm = dns.tsig.default_algorithm
self.request_mac = ''
self.other_data = ''
self.tsig_error = 0
self.fudge = 300
self.original_id = self.id
self.mac = ''
self.xfr = False
self.origin = None
self.tsig_ctx = None
self.had_tsig = False
self.multi = False
self.first = True
self.index = {}
def __repr__(self):
return '<DNS message, ID ' + repr(self.id) + '>'
def __str__(self):
return self.to_text()
def to_text(self, origin=None, relativize=True, **kw):
"""Convert the message to text.
The I{origin}, I{relativize}, and any other keyword
arguments are passed to the rrset to_wire() method.
@rtype: string
"""
s = StringIO()
s.write(u'id %d\n' % self.id)
s.write(u'opcode %s\n' %
dns.opcode.to_text(dns.opcode.from_flags(self.flags)))
rc = dns.rcode.from_flags(self.flags, self.ednsflags)
s.write(u'rcode %s\n' % dns.rcode.to_text(rc))
s.write(u'flags %s\n' % dns.flags.to_text(self.flags))
if self.edns >= 0:
s.write(u'edns %s\n' % self.edns)
if self.ednsflags != 0:
s.write(u'eflags %s\n' %
dns.flags.edns_to_text(self.ednsflags))
s.write(u'payload %d\n' % self.payload)
is_update = dns.opcode.is_update(self.flags)
if is_update:
s.write(u';ZONE\n')
else:
s.write(u';QUESTION\n')
for rrset in self.question:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
if is_update:
s.write(u';PREREQ\n')
else:
s.write(u';ANSWER\n')
for rrset in self.answer:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
if is_update:
s.write(u';UPDATE\n')
else:
s.write(u';AUTHORITY\n')
for rrset in self.authority:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
s.write(u';ADDITIONAL\n')
for rrset in self.additional:
s.write(rrset.to_text(origin, relativize, **kw))
s.write(u'\n')
#
# We strip off the final \n so the caller can print the result without
# doing weird things to get around eccentricities in Python print
# formatting
#
return s.getvalue()[:-1]
def __eq__(self, other):
"""Two messages are equal if they have the same content in the
header, question, answer, and authority sections.
@rtype: bool"""
if not isinstance(other, Message):
return False
if self.id != other.id:
return False
if self.flags != other.flags:
return False
for n in self.question:
if n not in other.question:
return False
for n in other.question:
if n not in self.question:
return False
for n in self.answer:
if n not in other.answer:
return False
for n in other.answer:
if n not in self.answer:
return False
for n in self.authority:
if n not in other.authority:
return False
for n in other.authority:
if n not in self.authority:
return False
return True
def __ne__(self, other):
"""Are two messages not equal?
@rtype: bool"""
return not self.__eq__(other)
def is_response(self, other):
"""Is other a response to self?
@rtype: bool"""
if other.flags & dns.flags.QR == 0 or \
self.id != other.id or \
dns.opcode.from_flags(self.flags) != \
dns.opcode.from_flags(other.flags):
return False
if dns.rcode.from_flags(other.flags, other.ednsflags) != \
dns.rcode.NOERROR:
return True
if dns.opcode.is_update(self.flags):
return True
for n in self.question:
if n not in other.question:
return False
for n in other.question:
if n not in self.question:
return False
return True
def section_number(self, section):
if section is self.question:
return 0
elif section is self.answer:
return 1
elif section is self.authority:
return 2
elif section is self.additional:
return 3
else:
raise ValueError('unknown section')
def find_rrset(self, section, name, rdclass, rdtype,
covers=dns.rdatatype.NONE, deleting=None, create=False,
force_unique=False):
"""Find the RRset with the given attributes in the specified section.
@param section: the section of the message to look in, e.g.
self.answer.
@type section: list of dns.rrset.RRset objects
@param name: the name of the RRset
@type name: dns.name.Name object
@param rdclass: the class of the RRset
@type rdclass: int
@param rdtype: the type of the RRset
@type rdtype: int
@param covers: the covers value of the RRset
@type covers: int
@param deleting: the deleting value of the RRset
@type deleting: int
@param create: If True, create the RRset if it is not found.
The created RRset is appended to I{section}.
@type create: bool
@param force_unique: If True and create is also True, create a
new RRset regardless of whether a matching RRset exists already.
@type force_unique: bool
@raises KeyError: the RRset was not found and create was False
@rtype: dns.rrset.RRset object"""
key = (self.section_number(section),
name, rdclass, rdtype, covers, deleting)
if not force_unique:
if self.index is not None:
rrset = self.index.get(key)
if rrset is not None:
return rrset
else:
for rrset in section:
if rrset.match(name, rdclass, rdtype, covers, deleting):
return rrset
if not create:
raise KeyError
rrset = dns.rrset.RRset(name, rdclass, rdtype, covers, deleting)
section.append(rrset)
if self.index is not None:
self.index[key] = rrset
return rrset
def get_rrset(self, section, name, rdclass, rdtype,
covers=dns.rdatatype.NONE, deleting=None, create=False,
force_unique=False):
"""Get the RRset with the given attributes in the specified section.
If the RRset is not found, None is returned.
@param section: the section of the message to look in, e.g.
self.answer.
@type section: list of dns.rrset.RRset objects
@param name: the name of the RRset
@type name: dns.name.Name object
@param rdclass: the class of the RRset
@type rdclass: int
@param rdtype: the type of the RRset
@type rdtype: int
@param covers: the covers value of the RRset
@type covers: int
@param deleting: the deleting value of the RRset
@type deleting: int
@param create: If True, create the RRset if it is not found.
The created RRset is appended to I{section}.
@type create: bool
@param force_unique: If True and create is also True, create a
new RRset regardless of whether a matching RRset exists already.
@type force_unique: bool
@rtype: dns.rrset.RRset object or None"""
try:
rrset = self.find_rrset(section, name, rdclass, rdtype, covers,
deleting, create, force_unique)
except KeyError:
rrset = None
return rrset
def to_wire(self, origin=None, max_size=0, **kw):
"""Return a string containing the message in DNS compressed wire
format.
Additional keyword arguments are passed to the rrset to_wire()
method.
@param origin: The origin to be appended to any relative names.
@type origin: dns.name.Name object
@param max_size: The maximum size of the wire format output; default
is 0, which means 'the message's request payload, if nonzero, or
65536'.
@type max_size: int
@raises dns.exception.TooBig: max_size was exceeded
@rtype: string
"""
if max_size == 0:
if self.request_payload != 0:
max_size = self.request_payload
else:
max_size = 65535
if max_size < 512:
max_size = 512
elif max_size > 65535:
max_size = 65535
r = dns.renderer.Renderer(self.id, self.flags, max_size, origin)
for rrset in self.question:
r.add_question(rrset.name, rrset.rdtype, rrset.rdclass)
for rrset in self.answer:
r.add_rrset(dns.renderer.ANSWER, rrset, **kw)
for rrset in self.authority:
r.add_rrset(dns.renderer.AUTHORITY, rrset, **kw)
if self.edns >= 0:
r.add_edns(self.edns, self.ednsflags, self.payload, self.options)
for rrset in self.additional:
r.add_rrset(dns.renderer.ADDITIONAL, rrset, **kw)
r.write_header()
if self.keyname is not None:
r.add_tsig(self.keyname, self.keyring[self.keyname],
self.fudge, self.original_id, self.tsig_error,
self.other_data, self.request_mac,
self.keyalgorithm)
self.mac = r.mac
return r.get_wire()
def use_tsig(self, keyring, keyname=None, fudge=300,
original_id=None, tsig_error=0, other_data='',
algorithm=dns.tsig.default_algorithm):
"""When sending, a TSIG signature using the specified keyring
and keyname should be added.
@param keyring: The TSIG keyring to use; defaults to None.
@type keyring: dict
@param keyname: The name of the TSIG key to use; defaults to None.
The key must be defined in the keyring. If a keyring is specified
but a keyname is not, then the key used will be the first key in the
keyring. Note that the order of keys in a dictionary is not defined,
so applications should supply a keyname when a keyring is used, unless
they know the keyring contains only one key.
@type keyname: dns.name.Name or string
@param fudge: TSIG time fudge; default is 300 seconds.
@type fudge: int
@param original_id: TSIG original id; defaults to the message's id
@type original_id: int
@param tsig_error: TSIG error code; default is 0.
@type tsig_error: int
@param other_data: TSIG other data.
@type other_data: string
@param algorithm: The TSIG algorithm to use; defaults to
dns.tsig.default_algorithm
"""
self.keyring = keyring
if keyname is None:
self.keyname = list(self.keyring.keys())[0]
else:
if isinstance(keyname, string_types):
keyname = dns.name.from_text(keyname)
self.keyname = keyname
self.keyalgorithm = algorithm
self.fudge = fudge
if original_id is None:
self.original_id = self.id
else:
self.original_id = original_id
self.tsig_error = tsig_error
self.other_data = other_data
def use_edns(self, edns=0, ednsflags=0, payload=1280, request_payload=None,
options=None):
"""Configure EDNS behavior.
@param edns: The EDNS level to use. Specifying None, False, or -1
means 'do not use EDNS', and in this case the other parameters are
ignored. Specifying True is equivalent to specifying 0, i.e. 'use
EDNS0'.
@type edns: int or bool or None
@param ednsflags: EDNS flag values.
@type ednsflags: int
@param payload: The EDNS sender's payload field, which is the maximum
size of UDP datagram the sender can handle.
@type payload: int
@param request_payload: The EDNS payload size to use when sending
this message. If not specified, defaults to the value of payload.
@type request_payload: int or None
@param options: The EDNS options
@type options: None or list of dns.edns.Option objects
@see: RFC 2671
"""
if edns is None or edns is False:
edns = -1
if edns is True:
edns = 0
if request_payload is None:
request_payload = payload
if edns < 0:
ednsflags = 0
payload = 0
request_payload = 0
options = []
else:
# make sure the EDNS version in ednsflags agrees with edns
ednsflags &= long(0xFF00FFFF)
ednsflags |= (edns << 16)
if options is None:
options = []
self.edns = edns
self.ednsflags = ednsflags
self.payload = payload
self.options = options
self.request_payload = request_payload
def want_dnssec(self, wanted=True):
"""Enable or disable 'DNSSEC desired' flag in requests.
@param wanted: Is DNSSEC desired? If True, EDNS is enabled if
required, and then the DO bit is set. If False, the DO bit is
cleared if EDNS is enabled.
@type wanted: bool
"""
if wanted:
if self.edns < 0:
self.use_edns()
self.ednsflags |= dns.flags.DO
elif self.edns >= 0:
self.ednsflags &= ~dns.flags.DO
def rcode(self):
"""Return the rcode.
@rtype: int
"""
return dns.rcode.from_flags(self.flags, self.ednsflags)
def set_rcode(self, rcode):
"""Set the rcode.
@param rcode: the rcode
@type rcode: int
"""
(value, evalue) = dns.rcode.to_flags(rcode)
self.flags &= 0xFFF0
self.flags |= value
self.ednsflags &= long(0x00FFFFFF)
self.ednsflags |= evalue
if self.ednsflags != 0 and self.edns < 0:
self.edns = 0
def opcode(self):
"""Return the opcode.
@rtype: int
"""
return dns.opcode.from_flags(self.flags)
def set_opcode(self, opcode):
"""Set the opcode.
@param opcode: the opcode
@type opcode: int
"""
self.flags &= 0x87FF
self.flags |= dns.opcode.to_flags(opcode)
class _WireReader(object):
"""Wire format reader.
@ivar wire: the wire-format message.
@type wire: string
@ivar message: The message object being built
@type message: dns.message.Message object
@ivar current: When building a message object from wire format, this
variable contains the offset from the beginning of wire of the next octet
to be read.
@type current: int
@ivar updating: Is the message a dynamic update?
@type updating: bool
@ivar one_rr_per_rrset: Put each RR into its own RRset?
@type one_rr_per_rrset: bool
@ivar ignore_trailing: Ignore trailing junk at end of request?
@type ignore_trailing: bool
@ivar zone_rdclass: The class of the zone in messages which are
DNS dynamic updates.
@type zone_rdclass: int
"""
def __init__(self, wire, message, question_only=False,
one_rr_per_rrset=False, ignore_trailing=False):
self.wire = dns.wiredata.maybe_wrap(wire)
self.message = message
self.current = 0
self.updating = False
self.zone_rdclass = dns.rdataclass.IN
self.question_only = question_only
self.one_rr_per_rrset = one_rr_per_rrset
self.ignore_trailing = ignore_trailing
def _get_question(self, qcount):
"""Read the next I{qcount} records from the wire data and add them to
the question section.
@param qcount: the number of questions in the message
@type qcount: int"""
if self.updating and qcount > 1:
raise dns.exception.FormError
for i in xrange(0, qcount):
(qname, used) = dns.name.from_wire(self.wire, self.current)
if self.message.origin is not None:
qname = qname.relativize(self.message.origin)
self.current = self.current + used
(rdtype, rdclass) = \
struct.unpack('!HH',
self.wire[self.current:self.current + 4])
self.current = self.current + 4
self.message.find_rrset(self.message.question, qname,
rdclass, rdtype, create=True,
force_unique=True)
if self.updating:
self.zone_rdclass = rdclass
def _get_section(self, section, count):
"""Read the next I{count} records from the wire data and add them to
the specified section.
@param section: the section of the message to which to add records
@type section: list of dns.rrset.RRset objects
@param count: the number of records to read
@type count: int"""
if self.updating or self.one_rr_per_rrset:
force_unique = True
else:
force_unique = False
seen_opt = False
for i in xrange(0, count):
rr_start = self.current
(name, used) = dns.name.from_wire(self.wire, self.current)
absolute_name = name
if self.message.origin is not None:
name = name.relativize(self.message.origin)
self.current = self.current + used
(rdtype, rdclass, ttl, rdlen) = \
struct.unpack('!HHIH',
self.wire[self.current:self.current + 10])
self.current = self.current + 10
if rdtype == dns.rdatatype.OPT:
if section is not self.message.additional or seen_opt:
raise BadEDNS
self.message.payload = rdclass
self.message.ednsflags = ttl
self.message.edns = (ttl & 0xff0000) >> 16
self.message.options = []
current = self.current
optslen = rdlen
while optslen > 0:
(otype, olen) = \
struct.unpack('!HH',
self.wire[current:current + 4])
current = current + 4
opt = dns.edns.option_from_wire(
otype, self.wire, current, olen)
self.message.options.append(opt)
current = current + olen
optslen = optslen - 4 - olen
seen_opt = True
elif rdtype == dns.rdatatype.TSIG:
if not (section is self.message.additional and
i == (count - 1)):
raise BadTSIG
if self.message.keyring is None:
raise UnknownTSIGKey('got signed message without keyring')
secret = self.message.keyring.get(absolute_name)
if secret is None:
raise UnknownTSIGKey("key '%s' unknown" % name)
self.message.keyname = absolute_name
(self.message.keyalgorithm, self.message.mac) = \
dns.tsig.get_algorithm_and_mac(self.wire, self.current,
rdlen)
self.message.tsig_ctx = \
dns.tsig.validate(self.wire,
absolute_name,
secret,
int(time.time()),
self.message.request_mac,
rr_start,
self.current,
rdlen,
self.message.tsig_ctx,
self.message.multi,
self.message.first)
self.message.had_tsig = True
else:
if ttl < 0:
ttl = 0
if self.updating and \
(rdclass == dns.rdataclass.ANY or
rdclass == dns.rdataclass.NONE):
deleting = rdclass
rdclass = self.zone_rdclass
else:
deleting = None
if deleting == dns.rdataclass.ANY or \
(deleting == dns.rdataclass.NONE and
section is self.message.answer):
covers = dns.rdatatype.NONE
rd = None
else:
rd = dns.rdata.from_wire(rdclass, rdtype, self.wire,
self.current, rdlen,
self.message.origin)
covers = rd.covers()
if self.message.xfr and rdtype == dns.rdatatype.SOA:
force_unique = True
rrset = self.message.find_rrset(section, name,
rdclass, rdtype, covers,
deleting, True, force_unique)
if rd is not None:
rrset.add(rd, ttl)
self.current = self.current + rdlen
def read(self):
"""Read a wire format DNS message and build a dns.message.Message
object."""
l = len(self.wire)
if l < 12:
raise ShortHeader
(self.message.id, self.message.flags, qcount, ancount,
aucount, adcount) = struct.unpack('!HHHHHH', self.wire[:12])
self.current = 12
if dns.opcode.is_update(self.message.flags):
self.updating = True
self._get_question(qcount)
if self.question_only:
return
self._get_section(self.message.answer, ancount)
self._get_section(self.message.authority, aucount)
self._get_section(self.message.additional, adcount)
if not self.ignore_trailing and self.current != l:
raise TrailingJunk
if self.message.multi and self.message.tsig_ctx and \
not self.message.had_tsig:
self.message.tsig_ctx.update(self.wire)
def from_wire(wire, keyring=None, request_mac='', xfr=False, origin=None,
tsig_ctx=None, multi=False, first=True,
question_only=False, one_rr_per_rrset=False,
ignore_trailing=False):
"""Convert a DNS wire format message into a message
object.
@param keyring: The keyring to use if the message is signed.
@type keyring: dict
@param request_mac: If the message is a response to a TSIG-signed request,
I{request_mac} should be set to the MAC of that request.
@type request_mac: string
@param xfr: Is this message part of a zone transfer?
@type xfr: bool
@param origin: If the message is part of a zone transfer, I{origin}
should be the origin name of the zone.
@type origin: dns.name.Name object
@param tsig_ctx: The ongoing TSIG context, used when validating zone
transfers.
@type tsig_ctx: hmac.HMAC object
@param multi: Is this message part of a multiple message sequence?
@type multi: bool
@param first: Is this message standalone, or the first of a multi
message sequence?
@type first: bool
@param question_only: Read only up to the end of the question section?
@type question_only: bool
@param one_rr_per_rrset: Put each RR into its own RRset
@type one_rr_per_rrset: bool
@param ignore_trailing: Ignore trailing junk at end of request?
@type ignore_trailing: bool
@raises ShortHeader: The message is less than 12 octets long.
@raises TrailingJunk: There were octets in the message past the end
of the proper DNS message.
@raises BadEDNS: An OPT record was in the wrong section, or occurred more
than once.
@raises BadTSIG: A TSIG record was not the last record of the additional
data section.
@rtype: dns.message.Message object"""
m = Message(id=0)
m.keyring = keyring
m.request_mac = request_mac
m.xfr = xfr
m.origin = origin
m.tsig_ctx = tsig_ctx
m.multi = multi
m.first = first
reader = _WireReader(wire, m, question_only, one_rr_per_rrset,
ignore_trailing)
reader.read()
return m
class _TextReader(object):
"""Text format reader.
@ivar tok: the tokenizer
@type tok: dns.tokenizer.Tokenizer object
@ivar message: The message object being built
@type message: dns.message.Message object
@ivar updating: Is the message a dynamic update?
@type updating: bool
@ivar zone_rdclass: The class of the zone in messages which are
DNS dynamic updates.
@type zone_rdclass: int
@ivar last_name: The most recently read name when building a message object
from text format.
@type last_name: dns.name.Name object
"""
def __init__(self, text, message):
self.message = message
self.tok = dns.tokenizer.Tokenizer(text)
self.last_name = None
self.zone_rdclass = dns.rdataclass.IN
self.updating = False
def _header_line(self, section):
"""Process one line from the text format header section."""
token = self.tok.get()
what = token.value
if what == 'id':
self.message.id = self.tok.get_int()
elif what == 'flags':
while True:
token = self.tok.get()
if not token.is_identifier():
self.tok.unget(token)
break
self.message.flags = self.message.flags | \
dns.flags.from_text(token.value)
if dns.opcode.is_update(self.message.flags):
self.updating = True
elif what == 'edns':
self.message.edns = self.tok.get_int()
self.message.ednsflags = self.message.ednsflags | \
(self.message.edns << 16)
elif what == 'eflags':
if self.message.edns < 0:
self.message.edns = 0
while True:
token = self.tok.get()
if not token.is_identifier():
self.tok.unget(token)
break
self.message.ednsflags = self.message.ednsflags | \
dns.flags.edns_from_text(token.value)
elif what == 'payload':
self.message.payload = self.tok.get_int()
if self.message.edns < 0:
self.message.edns = 0
elif what == 'opcode':
text = self.tok.get_string()
self.message.flags = self.message.flags | \
dns.opcode.to_flags(dns.opcode.from_text(text))
elif what == 'rcode':
text = self.tok.get_string()
self.message.set_rcode(dns.rcode.from_text(text))
else:
raise UnknownHeaderField
self.tok.get_eol()
def _question_line(self, section):
"""Process one line from the text format question section."""
token = self.tok.get(want_leading=True)
if not token.is_whitespace():
self.last_name = dns.name.from_text(token.value, None)
name = self.last_name
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
# Class
try:
rdclass = dns.rdataclass.from_text(token.value)
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
except dns.exception.SyntaxError:
raise dns.exception.SyntaxError
except Exception:
rdclass = dns.rdataclass.IN
# Type
rdtype = dns.rdatatype.from_text(token.value)
self.message.find_rrset(self.message.question, name,
rdclass, rdtype, create=True,
force_unique=True)
if self.updating:
self.zone_rdclass = rdclass
self.tok.get_eol()
def _rr_line(self, section):
"""Process one line from the text format answer, authority, or
additional data sections.
"""
deleting = None
# Name
token = self.tok.get(want_leading=True)
if not token.is_whitespace():
self.last_name = dns.name.from_text(token.value, None)
name = self.last_name
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
# TTL
try:
ttl = int(token.value, 0)
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
except dns.exception.SyntaxError:
raise dns.exception.SyntaxError
except Exception:
ttl = 0
# Class
try:
rdclass = dns.rdataclass.from_text(token.value)
token = self.tok.get()
if not token.is_identifier():
raise dns.exception.SyntaxError
if rdclass == dns.rdataclass.ANY or rdclass == dns.rdataclass.NONE:
deleting = rdclass
rdclass = self.zone_rdclass
except dns.exception.SyntaxError:
raise dns.exception.SyntaxError
except Exception:
rdclass = dns.rdataclass.IN
# Type
rdtype = dns.rdatatype.from_text(token.value)
token = self.tok.get()
if not token.is_eol_or_eof():
self.tok.unget(token)
rd = dns.rdata.from_text(rdclass, rdtype, self.tok, None)
covers = rd.covers()
else:
rd = None
covers = dns.rdatatype.NONE
rrset = self.message.find_rrset(section, name,
rdclass, rdtype, covers,
deleting, True, self.updating)
if rd is not None:
rrset.add(rd, ttl)
def read(self):
"""Read a text format DNS message and build a dns.message.Message
object."""
line_method = self._header_line
section = None
while 1:
token = self.tok.get(True, True)
if token.is_eol_or_eof():
break
if token.is_comment():
u = token.value.upper()
if u == 'HEADER':
line_method = self._header_line
elif u == 'QUESTION' or u == 'ZONE':
line_method = self._question_line
section = self.message.question
elif u == 'ANSWER' or u == 'PREREQ':
line_method = self._rr_line
section = self.message.answer
elif u == 'AUTHORITY' or u == 'UPDATE':
line_method = self._rr_line
section = self.message.authority
elif u == 'ADDITIONAL':
line_method = self._rr_line
section = self.message.additional
self.tok.get_eol()
continue
self.tok.unget(token)
line_method(section)
def from_text(text):
"""Convert the text format message into a message object.
@param text: The text format message.
@type text: string
@raises UnknownHeaderField:
@raises dns.exception.SyntaxError:
@rtype: dns.message.Message object"""
# 'text' can also be a file, but we don't publish that fact
# since it's an implementation detail. The official file
# interface is from_file().
m = Message()
reader = _TextReader(text, m)
reader.read()
return m
def from_file(f):
"""Read the next text format message from the specified file.
@param f: file or string. If I{f} is a string, it is treated
as the name of a file to open.
@raises UnknownHeaderField:
@raises dns.exception.SyntaxError:
@rtype: dns.message.Message object"""
str_type = string_types
opts = 'rU'
if isinstance(f, str_type):
f = open(f, opts)
want_close = True
else:
want_close = False
try:
m = from_text(f)
finally:
if want_close:
f.close()
return m
def make_query(qname, rdtype, rdclass=dns.rdataclass.IN, use_edns=None,
want_dnssec=False, ednsflags=None, payload=None,
request_payload=None, options=None):
"""Make a query message.
The query name, type, and class may all be specified either
as objects of the appropriate type, or as strings.
The query will have a randomly chosen query id, and its DNS flags
will be set to dns.flags.RD.
@param qname: The query name.
@type qname: dns.name.Name object or string
@param rdtype: The desired rdata type.
@type rdtype: int
@param rdclass: The desired rdata class; the default is class IN.
@type rdclass: int
@param use_edns: The EDNS level to use; the default is None (no EDNS).
See the description of dns.message.Message.use_edns() for the possible
values for use_edns and their meanings.
@type use_edns: int or bool or None
@param want_dnssec: Should the query indicate that DNSSEC is desired?
@type want_dnssec: bool
@param ednsflags: EDNS flag values.
@type ednsflags: int
@param payload: The EDNS sender's payload field, which is the maximum
size of UDP datagram the sender can handle.
@type payload: int
@param request_payload: The EDNS payload size to use when sending
this message. If not specified, defaults to the value of payload.
@type request_payload: int or None
@param options: The EDNS options
@type options: None or list of dns.edns.Option objects
@see: RFC 2671
@rtype: dns.message.Message object"""
if isinstance(qname, string_types):
qname = dns.name.from_text(qname)
if isinstance(rdtype, string_types):
rdtype = dns.rdatatype.from_text(rdtype)
if isinstance(rdclass, string_types):
rdclass = dns.rdataclass.from_text(rdclass)
m = Message()
m.flags |= dns.flags.RD
m.find_rrset(m.question, qname, rdclass, rdtype, create=True,
force_unique=True)
# only pass keywords on to use_edns if they have been set to a
# non-None value. Setting a field will turn EDNS on if it hasn't
# been configured.
kwargs = {}
if ednsflags is not None:
kwargs['ednsflags'] = ednsflags
if use_edns is None:
use_edns = 0
if payload is not None:
kwargs['payload'] = payload
if use_edns is None:
use_edns = 0
if request_payload is not None:
kwargs['request_payload'] = request_payload
if use_edns is None:
use_edns = 0
if options is not None:
kwargs['options'] = options
if use_edns is None:
use_edns = 0
kwargs['edns'] = use_edns
m.use_edns(**kwargs)
m.want_dnssec(want_dnssec)
return m
def make_response(query, recursion_available=False, our_payload=8192,
fudge=300):
"""Make a message which is a response for the specified query.
The message returned is really a response skeleton; it has all
of the infrastructure required of a response, but none of the
content.
The response's question section is a shallow copy of the query's
question section, so the query's question RRsets should not be
changed.
@param query: the query to respond to
@type query: dns.message.Message object
@param recursion_available: should RA be set in the response?
@type recursion_available: bool
@param our_payload: payload size to advertise in EDNS responses; default
is 8192.
@type our_payload: int
@param fudge: TSIG time fudge; default is 300 seconds.
@type fudge: int
@rtype: dns.message.Message object"""
if query.flags & dns.flags.QR:
raise dns.exception.FormError('specified query message is not a query')
response = dns.message.Message(query.id)
response.flags = dns.flags.QR | (query.flags & dns.flags.RD)
if recursion_available:
response.flags |= dns.flags.RA
response.set_opcode(query.opcode())
response.question = list(query.question)
if query.edns >= 0:
response.use_edns(0, 0, our_payload, query.payload)
if query.had_tsig:
response.use_tsig(query.keyring, query.keyname, fudge, None, 0, '',
query.keyalgorithm)
response.request_mac = query.mac
return response
lib64/python2.7/email/message.py 0000644 00000074003 15053001675 0012327 0 ustar 00 # Copyright (C) 2001-2006 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org
"""Basic message object for the email package object model."""
__all__ = ['Message']
import re
import uu
import binascii
import warnings
from cStringIO import StringIO
# Intrapackage imports
import email.charset
from email import utils
from email import errors
SEMISPACE = '; '
# Regular expression that matches `special' characters in parameters, the
# existence of which force quoting of the parameter value.
tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]')
# Helper functions
def _splitparam(param):
# Split header parameters. BAW: this may be too simple. It isn't
# strictly RFC 2045 (section 5.1) compliant, but it catches most headers
# found in the wild. We may eventually need a full fledged parser
# eventually.
a, sep, b = param.partition(';')
if not sep:
return a.strip(), None
return a.strip(), b.strip()
def _formatparam(param, value=None, quote=True):
"""Convenience function to format and return a key=value pair.
This will quote the value if needed or if quote is true. If value is a
three tuple (charset, language, value), it will be encoded according
to RFC2231 rules.
"""
if value is not None and len(value) > 0:
# A tuple is used for RFC 2231 encoded parameter values where items
# are (charset, language, value). charset is a string, not a Charset
# instance.
if isinstance(value, tuple):
# Encode as per RFC 2231
param += '*'
value = utils.encode_rfc2231(value[2], value[0], value[1])
# BAW: Please check this. I think that if quote is set it should
# force quoting even if not necessary.
if quote or tspecials.search(value):
return '%s="%s"' % (param, utils.quote(value))
else:
return '%s=%s' % (param, value)
else:
return param
def _parseparam(s):
plist = []
while s[:1] == ';':
s = s[1:]
end = s.find(';')
while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2:
end = s.find(';', end + 1)
if end < 0:
end = len(s)
f = s[:end]
if '=' in f:
i = f.index('=')
f = f[:i].strip().lower() + '=' + f[i+1:].strip()
plist.append(f.strip())
s = s[end:]
return plist
def _unquotevalue(value):
# This is different than utils.collapse_rfc2231_value() because it doesn't
# try to convert the value to a unicode. Message.get_param() and
# Message.get_params() are both currently defined to return the tuple in
# the face of RFC 2231 parameters.
if isinstance(value, tuple):
return value[0], value[1], utils.unquote(value[2])
else:
return utils.unquote(value)
class Message:
"""Basic message object.
A message object is defined as something that has a bunch of RFC 2822
headers and a payload. It may optionally have an envelope header
(a.k.a. Unix-From or From_ header). If the message is a container (i.e. a
multipart or a message/rfc822), then the payload is a list of Message
objects, otherwise it is a string.
Message objects implement part of the `mapping' interface, which assumes
there is exactly one occurrence of the header per message. Some headers
do in fact appear multiple times (e.g. Received) and for those headers,
you must use the explicit API to set or get all the headers. Not all of
the mapping methods are implemented.
"""
def __init__(self):
self._headers = []
self._unixfrom = None
self._payload = None
self._charset = None
# Defaults for multipart messages
self.preamble = self.epilogue = None
self.defects = []
# Default content type
self._default_type = 'text/plain'
def __str__(self):
"""Return the entire formatted message as a string.
This includes the headers, body, and envelope header.
"""
return self.as_string(unixfrom=True)
def as_string(self, unixfrom=False):
"""Return the entire formatted message as a string.
Optional `unixfrom' when True, means include the Unix From_ envelope
header.
This is a convenience method and may not generate the message exactly
as you intend because by default it mangles lines that begin with
"From ". For more flexibility, use the flatten() method of a
Generator instance.
"""
from email.generator import Generator
fp = StringIO()
g = Generator(fp)
g.flatten(self, unixfrom=unixfrom)
return fp.getvalue()
def is_multipart(self):
"""Return True if the message consists of multiple parts."""
return isinstance(self._payload, list)
#
# Unix From_ line
#
def set_unixfrom(self, unixfrom):
self._unixfrom = unixfrom
def get_unixfrom(self):
return self._unixfrom
#
# Payload manipulation.
#
def attach(self, payload):
"""Add the given payload to the current payload.
The current payload will always be a list of objects after this method
is called. If you want to set the payload to a scalar object, use
set_payload() instead.
"""
if self._payload is None:
self._payload = [payload]
else:
self._payload.append(payload)
def get_payload(self, i=None, decode=False):
"""Return a reference to the payload.
The payload will either be a list object or a string. If you mutate
the list object, you modify the message's payload in place. Optional
i returns that index into the payload.
Optional decode is a flag indicating whether the payload should be
decoded or not, according to the Content-Transfer-Encoding header
(default is False).
When True and the message is not a multipart, the payload will be
decoded if this header's value is `quoted-printable' or `base64'. If
some other encoding is used, or the header is missing, or if the
payload has bogus data (i.e. bogus base64 or uuencoded data), the
payload is returned as-is.
If the message is a multipart and the decode flag is True, then None
is returned.
"""
if i is None:
payload = self._payload
elif not isinstance(self._payload, list):
raise TypeError('Expected list, got %s' % type(self._payload))
else:
payload = self._payload[i]
if decode:
if self.is_multipart():
return None
cte = self.get('content-transfer-encoding', '').lower()
if cte == 'quoted-printable':
return utils._qdecode(payload)
elif cte == 'base64':
try:
return utils._bdecode(payload)
except binascii.Error:
# Incorrect padding
return payload
elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'):
sfp = StringIO()
try:
uu.decode(StringIO(payload+'\n'), sfp, quiet=True)
payload = sfp.getvalue()
except uu.Error:
# Some decoding problem
return payload
# Everything else, including encodings with 8bit or 7bit are returned
# unchanged.
return payload
def set_payload(self, payload, charset=None):
"""Set the payload to the given value.
Optional charset sets the message's default character set. See
set_charset() for details.
"""
self._payload = payload
if charset is not None:
self.set_charset(charset)
def set_charset(self, charset):
"""Set the charset of the payload to a given character set.
charset can be a Charset instance, a string naming a character set, or
None. If it is a string it will be converted to a Charset instance.
If charset is None, the charset parameter will be removed from the
Content-Type field. Anything else will generate a TypeError.
The message will be assumed to be of type text/* encoded with
charset.input_charset. It will be converted to charset.output_charset
and encoded properly, if needed, when generating the plain text
representation of the message. MIME headers (MIME-Version,
Content-Type, Content-Transfer-Encoding) will be added as needed.
"""
if charset is None:
self.del_param('charset')
self._charset = None
return
if isinstance(charset, basestring):
charset = email.charset.Charset(charset)
if not isinstance(charset, email.charset.Charset):
raise TypeError(charset)
# BAW: should we accept strings that can serve as arguments to the
# Charset constructor?
self._charset = charset
if 'MIME-Version' not in self:
self.add_header('MIME-Version', '1.0')
if 'Content-Type' not in self:
self.add_header('Content-Type', 'text/plain',
charset=charset.get_output_charset())
else:
self.set_param('charset', charset.get_output_charset())
if isinstance(self._payload, unicode):
self._payload = self._payload.encode(charset.output_charset)
if str(charset) != charset.get_output_charset():
self._payload = charset.body_encode(self._payload)
if 'Content-Transfer-Encoding' not in self:
cte = charset.get_body_encoding()
try:
cte(self)
except TypeError:
self._payload = charset.body_encode(self._payload)
self.add_header('Content-Transfer-Encoding', cte)
def get_charset(self):
"""Return the Charset instance associated with the message's payload.
"""
return self._charset
#
# MAPPING INTERFACE (partial)
#
def __len__(self):
"""Return the total number of headers, including duplicates."""
return len(self._headers)
def __getitem__(self, name):
"""Get a header value.
Return None if the header is missing instead of raising an exception.
Note that if the header appeared multiple times, exactly which
occurrence gets returned is undefined. Use get_all() to get all
the values matching a header field name.
"""
return self.get(name)
def __setitem__(self, name, val):
"""Set the value of a header.
Note: this does not overwrite an existing header with the same field
name. Use __delitem__() first to delete any existing headers.
"""
self._headers.append((name, val))
def __delitem__(self, name):
"""Delete all occurrences of a header, if present.
Does not raise an exception if the header is missing.
"""
name = name.lower()
newheaders = []
for k, v in self._headers:
if k.lower() != name:
newheaders.append((k, v))
self._headers = newheaders
def __contains__(self, name):
return name.lower() in [k.lower() for k, v in self._headers]
def has_key(self, name):
"""Return true if the message contains the header."""
missing = object()
return self.get(name, missing) is not missing
def keys(self):
"""Return a list of all the message's header field names.
These will be sorted in the order they appeared in the original
message, or were added to the message, and may contain duplicates.
Any fields deleted and re-inserted are always appended to the header
list.
"""
return [k for k, v in self._headers]
def values(self):
"""Return a list of all the message's header values.
These will be sorted in the order they appeared in the original
message, or were added to the message, and may contain duplicates.
Any fields deleted and re-inserted are always appended to the header
list.
"""
return [v for k, v in self._headers]
def items(self):
"""Get all the message's header fields and values.
These will be sorted in the order they appeared in the original
message, or were added to the message, and may contain duplicates.
Any fields deleted and re-inserted are always appended to the header
list.
"""
return self._headers[:]
def get(self, name, failobj=None):
"""Get a header value.
Like __getitem__() but return failobj instead of None when the field
is missing.
"""
name = name.lower()
for k, v in self._headers:
if k.lower() == name:
return v
return failobj
#
# Additional useful stuff
#
def get_all(self, name, failobj=None):
"""Return a list of all the values for the named field.
These will be sorted in the order they appeared in the original
message, and may contain duplicates. Any fields deleted and
re-inserted are always appended to the header list.
If no such fields exist, failobj is returned (defaults to None).
"""
values = []
name = name.lower()
for k, v in self._headers:
if k.lower() == name:
values.append(v)
if not values:
return failobj
return values
def add_header(self, _name, _value, **_params):
"""Extended header setting.
name is the header field to add. keyword arguments can be used to set
additional parameters for the header field, with underscores converted
to dashes. Normally the parameter will be added as key="value" unless
value is None, in which case only the key will be added. If a
parameter value contains non-ASCII characters it must be specified as a
three-tuple of (charset, language, value), in which case it will be
encoded according to RFC2231 rules.
Example:
msg.add_header('content-disposition', 'attachment', filename='bud.gif')
"""
parts = []
for k, v in _params.items():
if v is None:
parts.append(k.replace('_', '-'))
else:
parts.append(_formatparam(k.replace('_', '-'), v))
if _value is not None:
parts.insert(0, _value)
self._headers.append((_name, SEMISPACE.join(parts)))
def replace_header(self, _name, _value):
"""Replace a header.
Replace the first matching header found in the message, retaining
header order and case. If no matching header was found, a KeyError is
raised.
"""
_name = _name.lower()
for i, (k, v) in zip(range(len(self._headers)), self._headers):
if k.lower() == _name:
self._headers[i] = (k, _value)
break
else:
raise KeyError(_name)
#
# Use these three methods instead of the three above.
#
def get_content_type(self):
"""Return the message's content type.
The returned string is coerced to lower case of the form
`maintype/subtype'. If there was no Content-Type header in the
message, the default type as given by get_default_type() will be
returned. Since according to RFC 2045, messages always have a default
type this will always return a value.
RFC 2045 defines a message's default type to be text/plain unless it
appears inside a multipart/digest container, in which case it would be
message/rfc822.
"""
missing = object()
value = self.get('content-type', missing)
if value is missing:
# This should have no parameters
return self.get_default_type()
ctype = _splitparam(value)[0].lower()
# RFC 2045, section 5.2 says if its invalid, use text/plain
if ctype.count('/') != 1:
return 'text/plain'
return ctype
def get_content_maintype(self):
"""Return the message's main content type.
This is the `maintype' part of the string returned by
get_content_type().
"""
ctype = self.get_content_type()
return ctype.split('/')[0]
def get_content_subtype(self):
"""Returns the message's sub-content type.
This is the `subtype' part of the string returned by
get_content_type().
"""
ctype = self.get_content_type()
return ctype.split('/')[1]
def get_default_type(self):
"""Return the `default' content type.
Most messages have a default content type of text/plain, except for
messages that are subparts of multipart/digest containers. Such
subparts have a default content type of message/rfc822.
"""
return self._default_type
def set_default_type(self, ctype):
"""Set the `default' content type.
ctype should be either "text/plain" or "message/rfc822", although this
is not enforced. The default content type is not stored in the
Content-Type header.
"""
self._default_type = ctype
def _get_params_preserve(self, failobj, header):
# Like get_params() but preserves the quoting of values. BAW:
# should this be part of the public interface?
missing = object()
value = self.get(header, missing)
if value is missing:
return failobj
params = []
for p in _parseparam(';' + value):
try:
name, val = p.split('=', 1)
name = name.strip()
val = val.strip()
except ValueError:
# Must have been a bare attribute
name = p.strip()
val = ''
params.append((name, val))
params = utils.decode_params(params)
return params
def get_params(self, failobj=None, header='content-type', unquote=True):
"""Return the message's Content-Type parameters, as a list.
The elements of the returned list are 2-tuples of key/value pairs, as
split on the `=' sign. The left hand side of the `=' is the key,
while the right hand side is the value. If there is no `=' sign in
the parameter the value is the empty string. The value is as
described in the get_param() method.
Optional failobj is the object to return if there is no Content-Type
header. Optional header is the header to search instead of
Content-Type. If unquote is True, the value is unquoted.
"""
missing = object()
params = self._get_params_preserve(missing, header)
if params is missing:
return failobj
if unquote:
return [(k, _unquotevalue(v)) for k, v in params]
else:
return params
def get_param(self, param, failobj=None, header='content-type',
unquote=True):
"""Return the parameter value if found in the Content-Type header.
Optional failobj is the object to return if there is no Content-Type
header, or the Content-Type header has no such parameter. Optional
header is the header to search instead of Content-Type.
Parameter keys are always compared case insensitively. The return
value can either be a string, or a 3-tuple if the parameter was RFC
2231 encoded. When it's a 3-tuple, the elements of the value are of
the form (CHARSET, LANGUAGE, VALUE). Note that both CHARSET and
LANGUAGE can be None, in which case you should consider VALUE to be
encoded in the us-ascii charset. You can usually ignore LANGUAGE.
Your application should be prepared to deal with 3-tuple return
values, and can convert the parameter to a Unicode string like so:
param = msg.get_param('foo')
if isinstance(param, tuple):
param = unicode(param[2], param[0] or 'us-ascii')
In any case, the parameter value (either the returned string, or the
VALUE item in the 3-tuple) is always unquoted, unless unquote is set
to False.
"""
if header not in self:
return failobj
for k, v in self._get_params_preserve(failobj, header):
if k.lower() == param.lower():
if unquote:
return _unquotevalue(v)
else:
return v
return failobj
def set_param(self, param, value, header='Content-Type', requote=True,
charset=None, language=''):
"""Set a parameter in the Content-Type header.
If the parameter already exists in the header, its value will be
replaced with the new value.
If header is Content-Type and has not yet been defined for this
message, it will be set to "text/plain" and the new parameter and
value will be appended as per RFC 2045.
An alternate header can be specified in the header argument, and all
parameters will be quoted as necessary unless requote is False.
If charset is specified, the parameter will be encoded according to RFC
2231. Optional language specifies the RFC 2231 language, defaulting
to the empty string. Both charset and language should be strings.
"""
if not isinstance(value, tuple) and charset:
value = (charset, language, value)
if header not in self and header.lower() == 'content-type':
ctype = 'text/plain'
else:
ctype = self.get(header)
if not self.get_param(param, header=header):
if not ctype:
ctype = _formatparam(param, value, requote)
else:
ctype = SEMISPACE.join(
[ctype, _formatparam(param, value, requote)])
else:
ctype = ''
for old_param, old_value in self.get_params(header=header,
unquote=requote):
append_param = ''
if old_param.lower() == param.lower():
append_param = _formatparam(param, value, requote)
else:
append_param = _formatparam(old_param, old_value, requote)
if not ctype:
ctype = append_param
else:
ctype = SEMISPACE.join([ctype, append_param])
if ctype != self.get(header):
del self[header]
self[header] = ctype
def del_param(self, param, header='content-type', requote=True):
"""Remove the given parameter completely from the Content-Type header.
The header will be re-written in place without the parameter or its
value. All values will be quoted as necessary unless requote is
False. Optional header specifies an alternative to the Content-Type
header.
"""
if header not in self:
return
new_ctype = ''
for p, v in self.get_params(header=header, unquote=requote):
if p.lower() != param.lower():
if not new_ctype:
new_ctype = _formatparam(p, v, requote)
else:
new_ctype = SEMISPACE.join([new_ctype,
_formatparam(p, v, requote)])
if new_ctype != self.get(header):
del self[header]
self[header] = new_ctype
def set_type(self, type, header='Content-Type', requote=True):
"""Set the main type and subtype for the Content-Type header.
type must be a string in the form "maintype/subtype", otherwise a
ValueError is raised.
This method replaces the Content-Type header, keeping all the
parameters in place. If requote is False, this leaves the existing
header's quoting as is. Otherwise, the parameters will be quoted (the
default).
An alternative header can be specified in the header argument. When
the Content-Type header is set, we'll always also add a MIME-Version
header.
"""
# BAW: should we be strict?
if not type.count('/') == 1:
raise ValueError
# Set the Content-Type, you get a MIME-Version
if header.lower() == 'content-type':
del self['mime-version']
self['MIME-Version'] = '1.0'
if header not in self:
self[header] = type
return
params = self.get_params(header=header, unquote=requote)
del self[header]
self[header] = type
# Skip the first param; it's the old type.
for p, v in params[1:]:
self.set_param(p, v, header, requote)
def get_filename(self, failobj=None):
"""Return the filename associated with the payload if present.
The filename is extracted from the Content-Disposition header's
`filename' parameter, and it is unquoted. If that header is missing
the `filename' parameter, this method falls back to looking for the
`name' parameter.
"""
missing = object()
filename = self.get_param('filename', missing, 'content-disposition')
if filename is missing:
filename = self.get_param('name', missing, 'content-type')
if filename is missing:
return failobj
return utils.collapse_rfc2231_value(filename).strip()
def get_boundary(self, failobj=None):
"""Return the boundary associated with the payload if present.
The boundary is extracted from the Content-Type header's `boundary'
parameter, and it is unquoted.
"""
missing = object()
boundary = self.get_param('boundary', missing)
if boundary is missing:
return failobj
# RFC 2046 says that boundaries may begin but not end in w/s
return utils.collapse_rfc2231_value(boundary).rstrip()
def set_boundary(self, boundary):
"""Set the boundary parameter in Content-Type to 'boundary'.
This is subtly different than deleting the Content-Type header and
adding a new one with a new boundary parameter via add_header(). The
main difference is that using the set_boundary() method preserves the
order of the Content-Type header in the original message.
HeaderParseError is raised if the message has no Content-Type header.
"""
missing = object()
params = self._get_params_preserve(missing, 'content-type')
if params is missing:
# There was no Content-Type header, and we don't know what type
# to set it to, so raise an exception.
raise errors.HeaderParseError('No Content-Type header found')
newparams = []
foundp = False
for pk, pv in params:
if pk.lower() == 'boundary':
newparams.append(('boundary', '"%s"' % boundary))
foundp = True
else:
newparams.append((pk, pv))
if not foundp:
# The original Content-Type header had no boundary attribute.
# Tack one on the end. BAW: should we raise an exception
# instead???
newparams.append(('boundary', '"%s"' % boundary))
# Replace the existing Content-Type header with the new value
newheaders = []
for h, v in self._headers:
if h.lower() == 'content-type':
parts = []
for k, v in newparams:
if v == '':
parts.append(k)
else:
parts.append('%s=%s' % (k, v))
newheaders.append((h, SEMISPACE.join(parts)))
else:
newheaders.append((h, v))
self._headers = newheaders
def get_content_charset(self, failobj=None):
"""Return the charset parameter of the Content-Type header.
The returned string is always coerced to lower case. If there is no
Content-Type header, or if that header has no charset parameter,
failobj is returned.
"""
missing = object()
charset = self.get_param('charset', missing)
if charset is missing:
return failobj
if isinstance(charset, tuple):
# RFC 2231 encoded, so decode it, and it better end up as ascii.
pcharset = charset[0] or 'us-ascii'
try:
# LookupError will be raised if the charset isn't known to
# Python. UnicodeError will be raised if the encoded text
# contains a character not in the charset.
charset = unicode(charset[2], pcharset).encode('us-ascii')
except (LookupError, UnicodeError):
charset = charset[2]
# charset character must be in us-ascii range
try:
if isinstance(charset, str):
charset = unicode(charset, 'us-ascii')
charset = charset.encode('us-ascii')
except UnicodeError:
return failobj
# RFC 2046, $4.1.2 says charsets are not case sensitive
return charset.lower()
def get_charsets(self, failobj=None):
"""Return a list containing the charset(s) used in this message.
The returned list of items describes the Content-Type headers'
charset parameter for this message and all the subparts in its
payload.
Each item will either be a string (the value of the charset parameter
in the Content-Type header of that part) or the value of the
'failobj' parameter (defaults to None), if the part does not have a
main MIME type of "text", or the charset is not defined.
The list will contain one string for each part of the message, plus
one for the container message (i.e. self), so that a non-multipart
message will still return a list of length 1.
"""
return [part.get_content_charset(failobj) for part in self.walk()]
# I.e. def walk(self): ...
from email.iterators import walk