/usr/lib/python3/dist-packages/future/backports/email/generator.py is in python3-future 0.15.2-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 | # Copyright (C) 2001-2010 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org
"""Classes to generate plain text from a message object tree."""
from __future__ import print_function
from __future__ import unicode_literals
from __future__ import division
from __future__ import absolute_import
from future.builtins import super
from future.builtins import str
__all__ = ['Generator', 'DecodedGenerator', 'BytesGenerator']
import re
import sys
import time
import random
import warnings
from io import StringIO, BytesIO
from future.backports.email._policybase import compat32
from future.backports.email.header import Header
from future.backports.email.utils import _has_surrogates
import future.backports.email.charset as _charset
UNDERSCORE = '_'
NL = '\n' # XXX: no longer used by the code below.
fcre = re.compile(r'^From ', re.MULTILINE)
class Generator(object):
"""Generates output from a Message object tree.
This basic generator writes the message to the given file object as plain
text.
"""
#
# Public interface
#
def __init__(self, outfp, mangle_from_=True, maxheaderlen=None, **_3to2kwargs):
if 'policy' in _3to2kwargs: policy = _3to2kwargs['policy']; del _3to2kwargs['policy']
else: policy = None
"""Create the generator for message flattening.
outfp is the output file-like object for writing the message to. It
must have a write() method.
Optional mangle_from_ is a flag that, when True (the default), escapes
From_ lines in the body of the message by putting a `>' in front of
them.
Optional maxheaderlen specifies the longest length for a non-continued
header. When a header line is longer (in characters, with tabs
expanded to 8 spaces) than maxheaderlen, the header will split as
defined in the Header class. Set maxheaderlen to zero to disable
header wrapping. The default is 78, as recommended (but not required)
by RFC 2822.
The policy keyword specifies a policy object that controls a number of
aspects of the generator's operation. The default policy maintains
backward compatibility.
"""
self._fp = outfp
self._mangle_from_ = mangle_from_
self.maxheaderlen = maxheaderlen
self.policy = policy
def write(self, s):
# Just delegate to the file object
self._fp.write(s)
def flatten(self, msg, unixfrom=False, linesep=None):
r"""Print the message object tree rooted at msg to the output file
specified when the Generator instance was created.
unixfrom is a flag that forces the printing of a Unix From_ delimiter
before the first object in the message tree. If the original message
has no From_ delimiter, a `standard' one is crafted. By default, this
is False to inhibit the printing of any From_ delimiter.
Note that for subobjects, no From_ line is printed.
linesep specifies the characters used to indicate a new line in
the output. The default value is determined by the policy.
"""
# We use the _XXX constants for operating on data that comes directly
# from the msg, and _encoded_XXX constants for operating on data that
# has already been converted (to bytes in the BytesGenerator) and
# inserted into a temporary buffer.
policy = msg.policy if self.policy is None else self.policy
if linesep is not None:
policy = policy.clone(linesep=linesep)
if self.maxheaderlen is not None:
policy = policy.clone(max_line_length=self.maxheaderlen)
self._NL = policy.linesep
self._encoded_NL = self._encode(self._NL)
self._EMPTY = ''
self._encoded_EMTPY = self._encode('')
# Because we use clone (below) when we recursively process message
# subparts, and because clone uses the computed policy (not None),
# submessages will automatically get set to the computed policy when
# they are processed by this code.
old_gen_policy = self.policy
old_msg_policy = msg.policy
try:
self.policy = policy
msg.policy = policy
if unixfrom:
ufrom = msg.get_unixfrom()
if not ufrom:
ufrom = 'From nobody ' + time.ctime(time.time())
self.write(ufrom + self._NL)
self._write(msg)
finally:
self.policy = old_gen_policy
msg.policy = old_msg_policy
def clone(self, fp):
"""Clone this generator with the exact same options."""
return self.__class__(fp,
self._mangle_from_,
None, # Use policy setting, which we've adjusted
policy=self.policy)
#
# Protected interface - undocumented ;/
#
# Note that we use 'self.write' when what we are writing is coming from
# the source, and self._fp.write when what we are writing is coming from a
# buffer (because the Bytes subclass has already had a chance to transform
# the data in its write method in that case). This is an entirely
# pragmatic split determined by experiment; we could be more general by
# always using write and having the Bytes subclass write method detect when
# it has already transformed the input; but, since this whole thing is a
# hack anyway this seems good enough.
# Similarly, we have _XXX and _encoded_XXX attributes that are used on
# source and buffer data, respectively.
_encoded_EMPTY = ''
def _new_buffer(self):
# BytesGenerator overrides this to return BytesIO.
return StringIO()
def _encode(self, s):
# BytesGenerator overrides this to encode strings to bytes.
return s
def _write_lines(self, lines):
# We have to transform the line endings.
if not lines:
return
lines = lines.splitlines(True)
for line in lines[:-1]:
self.write(line.rstrip('\r\n'))
self.write(self._NL)
laststripped = lines[-1].rstrip('\r\n')
self.write(laststripped)
if len(lines[-1]) != len(laststripped):
self.write(self._NL)
def _write(self, msg):
# We can't write the headers yet because of the following scenario:
# say a multipart message includes the boundary string somewhere in
# its body. We'd have to calculate the new boundary /before/ we write
# the headers so that we can write the correct Content-Type:
# parameter.
#
# The way we do this, so as to make the _handle_*() methods simpler,
# is to cache any subpart writes into a buffer. The we write the
# headers and the buffer contents. That way, subpart handlers can
# Do The Right Thing, and can still modify the Content-Type: header if
# necessary.
oldfp = self._fp
try:
self._fp = sfp = self._new_buffer()
self._dispatch(msg)
finally:
self._fp = oldfp
# Write the headers. First we see if the message object wants to
# handle that itself. If not, we'll do it generically.
meth = getattr(msg, '_write_headers', None)
if meth is None:
self._write_headers(msg)
else:
meth(self)
self._fp.write(sfp.getvalue())
def _dispatch(self, msg):
# Get the Content-Type: for the message, then try to dispatch to
# self._handle_<maintype>_<subtype>(). If there's no handler for the
# full MIME type, then dispatch to self._handle_<maintype>(). If
# that's missing too, then dispatch to self._writeBody().
main = msg.get_content_maintype()
sub = msg.get_content_subtype()
specific = UNDERSCORE.join((main, sub)).replace('-', '_')
meth = getattr(self, '_handle_' + specific, None)
if meth is None:
generic = main.replace('-', '_')
meth = getattr(self, '_handle_' + generic, None)
if meth is None:
meth = self._writeBody
meth(msg)
#
# Default handlers
#
def _write_headers(self, msg):
for h, v in msg.raw_items():
self.write(self.policy.fold(h, v))
# A blank line always separates headers from body
self.write(self._NL)
#
# Handlers for writing types and subtypes
#
def _handle_text(self, msg):
payload = msg.get_payload()
if payload is None:
return
if not isinstance(payload, str):
raise TypeError('string payload expected: %s' % type(payload))
if _has_surrogates(msg._payload):
charset = msg.get_param('charset')
if charset is not None:
del msg['content-transfer-encoding']
msg.set_payload(payload, charset)
payload = msg.get_payload()
if self._mangle_from_:
payload = fcre.sub('>From ', payload)
self._write_lines(payload)
# Default body handler
_writeBody = _handle_text
def _handle_multipart(self, msg):
# The trick here is to write out each part separately, merge them all
# together, and then make sure that the boundary we've chosen isn't
# present in the payload.
msgtexts = []
subparts = msg.get_payload()
if subparts is None:
subparts = []
elif isinstance(subparts, str):
# e.g. a non-strict parse of a message with no starting boundary.
self.write(subparts)
return
elif not isinstance(subparts, list):
# Scalar payload
subparts = [subparts]
for part in subparts:
s = self._new_buffer()
g = self.clone(s)
g.flatten(part, unixfrom=False, linesep=self._NL)
msgtexts.append(s.getvalue())
# BAW: What about boundaries that are wrapped in double-quotes?
boundary = msg.get_boundary()
if not boundary:
# Create a boundary that doesn't appear in any of the
# message texts.
alltext = self._encoded_NL.join(msgtexts)
boundary = self._make_boundary(alltext)
msg.set_boundary(boundary)
# If there's a preamble, write it out, with a trailing CRLF
if msg.preamble is not None:
if self._mangle_from_:
preamble = fcre.sub('>From ', msg.preamble)
else:
preamble = msg.preamble
self._write_lines(preamble)
self.write(self._NL)
# dash-boundary transport-padding CRLF
self.write('--' + boundary + self._NL)
# body-part
if msgtexts:
self._fp.write(msgtexts.pop(0))
# *encapsulation
# --> delimiter transport-padding
# --> CRLF body-part
for body_part in msgtexts:
# delimiter transport-padding CRLF
self.write(self._NL + '--' + boundary + self._NL)
# body-part
self._fp.write(body_part)
# close-delimiter transport-padding
self.write(self._NL + '--' + boundary + '--')
if msg.epilogue is not None:
self.write(self._NL)
if self._mangle_from_:
epilogue = fcre.sub('>From ', msg.epilogue)
else:
epilogue = msg.epilogue
self._write_lines(epilogue)
def _handle_multipart_signed(self, msg):
# The contents of signed parts has to stay unmodified in order to keep
# the signature intact per RFC1847 2.1, so we disable header wrapping.
# RDM: This isn't enough to completely preserve the part, but it helps.
p = self.policy
self.policy = p.clone(max_line_length=0)
try:
self._handle_multipart(msg)
finally:
self.policy = p
def _handle_message_delivery_status(self, msg):
# We can't just write the headers directly to self's file object
# because this will leave an extra newline between the last header
# block and the boundary. Sigh.
blocks = []
for part in msg.get_payload():
s = self._new_buffer()
g = self.clone(s)
g.flatten(part, unixfrom=False, linesep=self._NL)
text = s.getvalue()
lines = text.split(self._encoded_NL)
# Strip off the unnecessary trailing empty line
if lines and lines[-1] == self._encoded_EMPTY:
blocks.append(self._encoded_NL.join(lines[:-1]))
else:
blocks.append(text)
# Now join all the blocks with an empty line. This has the lovely
# effect of separating each block with an empty line, but not adding
# an extra one after the last one.
self._fp.write(self._encoded_NL.join(blocks))
def _handle_message(self, msg):
s = self._new_buffer()
g = self.clone(s)
# The payload of a message/rfc822 part should be a multipart sequence
# of length 1. The zeroth element of the list should be the Message
# object for the subpart. Extract that object, stringify it, and
# write it out.
# Except, it turns out, when it's a string instead, which happens when
# and only when HeaderParser is used on a message of mime type
# message/rfc822. Such messages are generated by, for example,
# Groupwise when forwarding unadorned messages. (Issue 7970.) So
# in that case we just emit the string body.
payload = msg._payload
if isinstance(payload, list):
g.flatten(msg.get_payload(0), unixfrom=False, linesep=self._NL)
payload = s.getvalue()
else:
payload = self._encode(payload)
self._fp.write(payload)
# This used to be a module level function; we use a classmethod for this
# and _compile_re so we can continue to provide the module level function
# for backward compatibility by doing
# _make_boudary = Generator._make_boundary
# at the end of the module. It *is* internal, so we could drop that...
@classmethod
def _make_boundary(cls, text=None):
# Craft a random boundary. If text is given, ensure that the chosen
# boundary doesn't appear in the text.
token = random.randrange(sys.maxsize)
boundary = ('=' * 15) + (_fmt % token) + '=='
if text is None:
return boundary
b = boundary
counter = 0
while True:
cre = cls._compile_re('^--' + re.escape(b) + '(--)?$', re.MULTILINE)
if not cre.search(text):
break
b = boundary + '.' + str(counter)
counter += 1
return b
@classmethod
def _compile_re(cls, s, flags):
return re.compile(s, flags)
class BytesGenerator(Generator):
"""Generates a bytes version of a Message object tree.
Functionally identical to the base Generator except that the output is
bytes and not string. When surrogates were used in the input to encode
bytes, these are decoded back to bytes for output. If the policy has
cte_type set to 7bit, then the message is transformed such that the
non-ASCII bytes are properly content transfer encoded, using the charset
unknown-8bit.
The outfp object must accept bytes in its write method.
"""
# Bytes versions of this constant for use in manipulating data from
# the BytesIO buffer.
_encoded_EMPTY = b''
def write(self, s):
self._fp.write(str(s).encode('ascii', 'surrogateescape'))
def _new_buffer(self):
return BytesIO()
def _encode(self, s):
return s.encode('ascii')
def _write_headers(self, msg):
# This is almost the same as the string version, except for handling
# strings with 8bit bytes.
for h, v in msg.raw_items():
self._fp.write(self.policy.fold_binary(h, v))
# A blank line always separates headers from body
self.write(self._NL)
def _handle_text(self, msg):
# If the string has surrogates the original source was bytes, so
# just write it back out.
if msg._payload is None:
return
if _has_surrogates(msg._payload) and not self.policy.cte_type=='7bit':
if self._mangle_from_:
msg._payload = fcre.sub(">From ", msg._payload)
self._write_lines(msg._payload)
else:
super(BytesGenerator,self)._handle_text(msg)
# Default body handler
_writeBody = _handle_text
@classmethod
def _compile_re(cls, s, flags):
return re.compile(s.encode('ascii'), flags)
_FMT = '[Non-text (%(type)s) part of message omitted, filename %(filename)s]'
class DecodedGenerator(Generator):
"""Generates a text representation of a message.
Like the Generator base class, except that non-text parts are substituted
with a format string representing the part.
"""
def __init__(self, outfp, mangle_from_=True, maxheaderlen=78, fmt=None):
"""Like Generator.__init__() except that an additional optional
argument is allowed.
Walks through all subparts of a message. If the subpart is of main
type `text', then it prints the decoded payload of the subpart.
Otherwise, fmt is a format string that is used instead of the message
payload. fmt is expanded with the following keywords (in
%(keyword)s format):
type : Full MIME type of the non-text part
maintype : Main MIME type of the non-text part
subtype : Sub-MIME type of the non-text part
filename : Filename of the non-text part
description: Description associated with the non-text part
encoding : Content transfer encoding of the non-text part
The default value for fmt is None, meaning
[Non-text (%(type)s) part of message omitted, filename %(filename)s]
"""
Generator.__init__(self, outfp, mangle_from_, maxheaderlen)
if fmt is None:
self._fmt = _FMT
else:
self._fmt = fmt
def _dispatch(self, msg):
for part in msg.walk():
maintype = part.get_content_maintype()
if maintype == 'text':
print(part.get_payload(decode=False), file=self)
elif maintype == 'multipart':
# Just skip this
pass
else:
print(self._fmt % {
'type' : part.get_content_type(),
'maintype' : part.get_content_maintype(),
'subtype' : part.get_content_subtype(),
'filename' : part.get_filename('[no filename]'),
'description': part.get('Content-Description',
'[no description]'),
'encoding' : part.get('Content-Transfer-Encoding',
'[no encoding]'),
}, file=self)
# Helper used by Generator._make_boundary
_width = len(repr(sys.maxsize-1))
_fmt = '%%0%dd' % _width
# Backward compatibility
_make_boundary = Generator._make_boundary
|