/Lib/email/message.py
Python | 790 lines | 724 code | 14 blank | 52 comment | 21 complexity | d7c39457414798d54a8f90bbca57b8b1 MD5 | raw file
1# Copyright (C) 2001-2006 Python Software Foundation 2# Author: Barry Warsaw 3# Contact: email-sig@python.org 4 5"""Basic message object for the email package object model.""" 6 7__all__ = ['Message'] 8 9import re 10import uu 11import binascii 12import warnings 13from cStringIO import StringIO 14 15# Intrapackage imports 16import email.charset 17from email import utils 18from email import errors 19 20SEMISPACE = '; ' 21 22# Regular expression that matches `special' characters in parameters, the 23# existence of which force quoting of the parameter value. 24tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]') 25 26 27# Helper functions 28def _splitparam(param): 29 # Split header parameters. BAW: this may be too simple. It isn't 30 # strictly RFC 2045 (section 5.1) compliant, but it catches most headers 31 # found in the wild. We may eventually need a full fledged parser 32 # eventually. 33 a, sep, b = param.partition(';') 34 if not sep: 35 return a.strip(), None 36 return a.strip(), b.strip() 37 38def _formatparam(param, value=None, quote=True): 39 """Convenience function to format and return a key=value pair. 40 41 This will quote the value if needed or if quote is true. 42 """ 43 if value is not None and len(value) > 0: 44 # A tuple is used for RFC 2231 encoded parameter values where items 45 # are (charset, language, value). charset is a string, not a Charset 46 # instance. 47 if isinstance(value, tuple): 48 # Encode as per RFC 2231 49 param += '*' 50 value = utils.encode_rfc2231(value[2], value[0], value[1]) 51 # BAW: Please check this. I think that if quote is set it should 52 # force quoting even if not necessary. 53 if quote or tspecials.search(value): 54 return '%s="%s"' % (param, utils.quote(value)) 55 else: 56 return '%s=%s' % (param, value) 57 else: 58 return param 59 60def _parseparam(s): 61 plist = [] 62 while s[:1] == ';': 63 s = s[1:] 64 end = s.find(';') 65 while end > 0 and s.count('"', 0, end) % 2: 66 end = s.find(';', end + 1) 67 if end < 0: 68 end = len(s) 69 f = s[:end] 70 if '=' in f: 71 i = f.index('=') 72 f = f[:i].strip().lower() + '=' + f[i+1:].strip() 73 plist.append(f.strip()) 74 s = s[end:] 75 return plist 76 77 78def _unquotevalue(value): 79 # This is different than utils.collapse_rfc2231_value() because it doesn't 80 # try to convert the value to a unicode. Message.get_param() and 81 # Message.get_params() are both currently defined to return the tuple in 82 # the face of RFC 2231 parameters. 83 if isinstance(value, tuple): 84 return value[0], value[1], utils.unquote(value[2]) 85 else: 86 return utils.unquote(value) 87 88 89 90class Message: 91 """Basic message object. 92 93 A message object is defined as something that has a bunch of RFC 2822 94 headers and a payload. It may optionally have an envelope header 95 (a.k.a. Unix-From or From_ header). If the message is a container (i.e. a 96 multipart or a message/rfc822), then the payload is a list of Message 97 objects, otherwise it is a string. 98 99 Message objects implement part of the `mapping' interface, which assumes 100 there is exactly one occurrance of the header per message. Some headers 101 do in fact appear multiple times (e.g. Received) and for those headers, 102 you must use the explicit API to set or get all the headers. Not all of 103 the mapping methods are implemented. 104 """ 105 def __init__(self): 106 self._headers = [] 107 self._unixfrom = None 108 self._payload = None 109 self._charset = None 110 # Defaults for multipart messages 111 self.preamble = self.epilogue = None 112 self.defects = [] 113 # Default content type 114 self._default_type = 'text/plain' 115 116 def __str__(self): 117 """Return the entire formatted message as a string. 118 This includes the headers, body, and envelope header. 119 """ 120 return self.as_string(unixfrom=True) 121 122 def as_string(self, unixfrom=False): 123 """Return the entire formatted message as a string. 124 Optional `unixfrom' when True, means include the Unix From_ envelope 125 header. 126 127 This is a convenience method and may not generate the message exactly 128 as you intend because by default it mangles lines that begin with 129 "From ". For more flexibility, use the flatten() method of a 130 Generator instance. 131 """ 132 from email.generator import Generator 133 fp = StringIO() 134 g = Generator(fp) 135 g.flatten(self, unixfrom=unixfrom) 136 return fp.getvalue() 137 138 def is_multipart(self): 139 """Return True if the message consists of multiple parts.""" 140 return isinstance(self._payload, list) 141 142 # 143 # Unix From_ line 144 # 145 def set_unixfrom(self, unixfrom): 146 self._unixfrom = unixfrom 147 148 def get_unixfrom(self): 149 return self._unixfrom 150 151 # 152 # Payload manipulation. 153 # 154 def attach(self, payload): 155 """Add the given payload to the current payload. 156 157 The current payload will always be a list of objects after this method 158 is called. If you want to set the payload to a scalar object, use 159 set_payload() instead. 160 """ 161 if self._payload is None: 162 self._payload = [payload] 163 else: 164 self._payload.append(payload) 165 166 def get_payload(self, i=None, decode=False): 167 """Return a reference to the payload. 168 169 The payload will either be a list object or a string. If you mutate 170 the list object, you modify the message's payload in place. Optional 171 i returns that index into the payload. 172 173 Optional decode is a flag indicating whether the payload should be 174 decoded or not, according to the Content-Transfer-Encoding header 175 (default is False). 176 177 When True and the message is not a multipart, the payload will be 178 decoded if this header's value is `quoted-printable' or `base64'. If 179 some other encoding is used, or the header is missing, or if the 180 payload has bogus data (i.e. bogus base64 or uuencoded data), the 181 payload is returned as-is. 182 183 If the message is a multipart and the decode flag is True, then None 184 is returned. 185 """ 186 if i is None: 187 payload = self._payload 188 elif not isinstance(self._payload, list): 189 raise TypeError('Expected list, got %s' % type(self._payload)) 190 else: 191 payload = self._payload[i] 192 if decode: 193 if self.is_multipart(): 194 return None 195 cte = self.get('content-transfer-encoding', '').lower() 196 if cte == 'quoted-printable': 197 return utils._qdecode(payload) 198 elif cte == 'base64': 199 try: 200 return utils._bdecode(payload) 201 except binascii.Error: 202 # Incorrect padding 203 return payload 204 elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'): 205 sfp = StringIO() 206 try: 207 uu.decode(StringIO(payload+'\n'), sfp, quiet=True) 208 payload = sfp.getvalue() 209 except uu.Error: 210 # Some decoding problem 211 return payload 212 # Everything else, including encodings with 8bit or 7bit are returned 213 # unchanged. 214 return payload 215 216 def set_payload(self, payload, charset=None): 217 """Set the payload to the given value. 218 219 Optional charset sets the message's default character set. See 220 set_charset() for details. 221 """ 222 self._payload = payload 223 if charset is not None: 224 self.set_charset(charset) 225 226 def set_charset(self, charset): 227 """Set the charset of the payload to a given character set. 228 229 charset can be a Charset instance, a string naming a character set, or 230 None. If it is a string it will be converted to a Charset instance. 231 If charset is None, the charset parameter will be removed from the 232 Content-Type field. Anything else will generate a TypeError. 233 234 The message will be assumed to be of type text/* encoded with 235 charset.input_charset. It will be converted to charset.output_charset 236 and encoded properly, if needed, when generating the plain text 237 representation of the message. MIME headers (MIME-Version, 238 Content-Type, Content-Transfer-Encoding) will be added as needed. 239 240 """ 241 if charset is None: 242 self.del_param('charset') 243 self._charset = None 244 return 245 if isinstance(charset, basestring): 246 charset = email.charset.Charset(charset) 247 if not isinstance(charset, email.charset.Charset): 248 raise TypeError(charset) 249 # BAW: should we accept strings that can serve as arguments to the 250 # Charset constructor? 251 self._charset = charset 252 if not self.has_key('MIME-Version'): 253 self.add_header('MIME-Version', '1.0') 254 if not self.has_key('Content-Type'): 255 self.add_header('Content-Type', 'text/plain', 256 charset=charset.get_output_charset()) 257 else: 258 self.set_param('charset', charset.get_output_charset()) 259 if str(charset) != charset.get_output_charset(): 260 self._payload = charset.body_encode(self._payload) 261 if not self.has_key('Content-Transfer-Encoding'): 262 cte = charset.get_body_encoding() 263 try: 264 cte(self) 265 except TypeError: 266 self._payload = charset.body_encode(self._payload) 267 self.add_header('Content-Transfer-Encoding', cte) 268 269 def get_charset(self): 270 """Return the Charset instance associated with the message's payload. 271 """ 272 return self._charset 273 274 # 275 # MAPPING INTERFACE (partial) 276 # 277 def __len__(self): 278 """Return the total number of headers, including duplicates.""" 279 return len(self._headers) 280 281 def __getitem__(self, name): 282 """Get a header value. 283 284 Return None if the header is missing instead of raising an exception. 285 286 Note that if the header appeared multiple times, exactly which 287 occurrance gets returned is undefined. Use get_all() to get all 288 the values matching a header field name. 289 """ 290 return self.get(name) 291 292 def __setitem__(self, name, val): 293 """Set the value of a header. 294 295 Note: this does not overwrite an existing header with the same field 296 name. Use __delitem__() first to delete any existing headers. 297 """ 298 self._headers.append((name, val)) 299 300 def __delitem__(self, name): 301 """Delete all occurrences of a header, if present. 302 303 Does not raise an exception if the header is missing. 304 """ 305 name = name.lower() 306 newheaders = [] 307 for k, v in self._headers: 308 if k.lower() != name: 309 newheaders.append((k, v)) 310 self._headers = newheaders 311 312 def __contains__(self, name): 313 return name.lower() in [k.lower() for k, v in self._headers] 314 315 def has_key(self, name): 316 """Return true if the message contains the header.""" 317 missing = object() 318 return self.get(name, missing) is not missing 319 320 def keys(self): 321 """Return a list of all the message's header field names. 322 323 These will be sorted in the order they appeared in the original 324 message, or were added to the message, and may contain duplicates. 325 Any fields deleted and re-inserted are always appended to the header 326 list. 327 """ 328 return [k for k, v in self._headers] 329 330 def values(self): 331 """Return a list of all the message's header values. 332 333 These will be sorted in the order they appeared in the original 334 message, or were added to the message, and may contain duplicates. 335 Any fields deleted and re-inserted are always appended to the header 336 list. 337 """ 338 return [v for k, v in self._headers] 339 340 def items(self): 341 """Get all the message's header fields and values. 342 343 These will be sorted in the order they appeared in the original 344 message, or were added to the message, and may contain duplicates. 345 Any fields deleted and re-inserted are always appended to the header 346 list. 347 """ 348 return self._headers[:] 349 350 def get(self, name, failobj=None): 351 """Get a header value. 352 353 Like __getitem__() but return failobj instead of None when the field 354 is missing. 355 """ 356 name = name.lower() 357 for k, v in self._headers: 358 if k.lower() == name: 359 return v 360 return failobj 361 362 # 363 # Additional useful stuff 364 # 365 366 def get_all(self, name, failobj=None): 367 """Return a list of all the values for the named field. 368 369 These will be sorted in the order they appeared in the original 370 message, and may contain duplicates. Any fields deleted and 371 re-inserted are always appended to the header list. 372 373 If no such fields exist, failobj is returned (defaults to None). 374 """ 375 values = [] 376 name = name.lower() 377 for k, v in self._headers: 378 if k.lower() == name: 379 values.append(v) 380 if not values: 381 return failobj 382 return values 383 384 def add_header(self, _name, _value, **_params): 385 """Extended header setting. 386 387 name is the header field to add. keyword arguments can be used to set 388 additional parameters for the header field, with underscores converted 389 to dashes. Normally the parameter will be added as key="value" unless 390 value is None, in which case only the key will be added. 391 392 Example: 393 394 msg.add_header('content-disposition', 'attachment', filename='bud.gif') 395 """ 396 parts = [] 397 for k, v in _params.items(): 398 if v is None: 399 parts.append(k.replace('_', '-')) 400 else: 401 parts.append(_formatparam(k.replace('_', '-'), v)) 402 if _value is not None: 403 parts.insert(0, _value) 404 self._headers.append((_name, SEMISPACE.join(parts))) 405 406 def replace_header(self, _name, _value): 407 """Replace a header. 408 409 Replace the first matching header found in the message, retaining 410 header order and case. If no matching header was found, a KeyError is 411 raised. 412 """ 413 _name = _name.lower() 414 for i, (k, v) in zip(range(len(self._headers)), self._headers): 415 if k.lower() == _name: 416 self._headers[i] = (k, _value) 417 break 418 else: 419 raise KeyError(_name) 420 421 # 422 # Use these three methods instead of the three above. 423 # 424 425 def get_content_type(self): 426 """Return the message's content type. 427 428 The returned string is coerced to lower case of the form 429 `maintype/subtype'. If there was no Content-Type header in the 430 message, the default type as given by get_default_type() will be 431 returned. Since according to RFC 2045, messages always have a default 432 type this will always return a value. 433 434 RFC 2045 defines a message's default type to be text/plain unless it 435 appears inside a multipart/digest container, in which case it would be 436 message/rfc822. 437 """ 438 missing = object() 439 value = self.get('content-type', missing) 440 if value is missing: 441 # This should have no parameters 442 return self.get_default_type() 443 ctype = _splitparam(value)[0].lower() 444 # RFC 2045, section 5.2 says if its invalid, use text/plain 445 if ctype.count('/') != 1: 446 return 'text/plain' 447 return ctype 448 449 def get_content_maintype(self): 450 """Return the message's main content type. 451 452 This is the `maintype' part of the string returned by 453 get_content_type(). 454 """ 455 ctype = self.get_content_type() 456 return ctype.split('/')[0] 457 458 def get_content_subtype(self): 459 """Returns the message's sub-content type. 460 461 This is the `subtype' part of the string returned by 462 get_content_type(). 463 """ 464 ctype = self.get_content_type() 465 return ctype.split('/')[1] 466 467 def get_default_type(self): 468 """Return the `default' content type. 469 470 Most messages have a default content type of text/plain, except for 471 messages that are subparts of multipart/digest containers. Such 472 subparts have a default content type of message/rfc822. 473 """ 474 return self._default_type 475 476 def set_default_type(self, ctype): 477 """Set the `default' content type. 478 479 ctype should be either "text/plain" or "message/rfc822", although this 480 is not enforced. The default content type is not stored in the 481 Content-Type header. 482 """ 483 self._default_type = ctype 484 485 def _get_params_preserve(self, failobj, header): 486 # Like get_params() but preserves the quoting of values. BAW: 487 # should this be part of the public interface? 488 missing = object() 489 value = self.get(header, missing) 490 if value is missing: 491 return failobj 492 params = [] 493 for p in _parseparam(';' + value): 494 try: 495 name, val = p.split('=', 1) 496 name = name.strip() 497 val = val.strip() 498 except ValueError: 499 # Must have been a bare attribute 500 name = p.strip() 501 val = '' 502 params.append((name, val)) 503 params = utils.decode_params(params) 504 return params 505 506 def get_params(self, failobj=None, header='content-type', unquote=True): 507 """Return the message's Content-Type parameters, as a list. 508 509 The elements of the returned list are 2-tuples of key/value pairs, as 510 split on the `=' sign. The left hand side of the `=' is the key, 511 while the right hand side is the value. If there is no `=' sign in 512 the parameter the value is the empty string. The value is as 513 described in the get_param() method. 514 515 Optional failobj is the object to return if there is no Content-Type 516 header. Optional header is the header to search instead of 517 Content-Type. If unquote is True, the value is unquoted. 518 """ 519 missing = object() 520 params = self._get_params_preserve(missing, header) 521 if params is missing: 522 return failobj 523 if unquote: 524 return [(k, _unquotevalue(v)) for k, v in params] 525 else: 526 return params 527 528 def get_param(self, param, failobj=None, header='content-type', 529 unquote=True): 530 """Return the parameter value if found in the Content-Type header. 531 532 Optional failobj is the object to return if there is no Content-Type 533 header, or the Content-Type header has no such parameter. Optional 534 header is the header to search instead of Content-Type. 535 536 Parameter keys are always compared case insensitively. The return 537 value can either be a string, or a 3-tuple if the parameter was RFC 538 2231 encoded. When it's a 3-tuple, the elements of the value are of 539 the form (CHARSET, LANGUAGE, VALUE). Note that both CHARSET and 540 LANGUAGE can be None, in which case you should consider VALUE to be 541 encoded in the us-ascii charset. You can usually ignore LANGUAGE. 542 543 Your application should be prepared to deal with 3-tuple return 544 values, and can convert the parameter to a Unicode string like so: 545 546 param = msg.get_param('foo') 547 if isinstance(param, tuple): 548 param = unicode(param[2], param[0] or 'us-ascii') 549 550 In any case, the parameter value (either the returned string, or the 551 VALUE item in the 3-tuple) is always unquoted, unless unquote is set 552 to False. 553 """ 554 if not self.has_key(header): 555 return failobj 556 for k, v in self._get_params_preserve(failobj, header): 557 if k.lower() == param.lower(): 558 if unquote: 559 return _unquotevalue(v) 560 else: 561 return v 562 return failobj 563 564 def set_param(self, param, value, header='Content-Type', requote=True, 565 charset=None, language=''): 566 """Set a parameter in the Content-Type header. 567 568 If the parameter already exists in the header, its value will be 569 replaced with the new value. 570 571 If header is Content-Type and has not yet been defined for this 572 message, it will be set to "text/plain" and the new parameter and 573 value will be appended as per RFC 2045. 574 575 An alternate header can specified in the header argument, and all 576 parameters will be quoted as necessary unless requote is False. 577 578 If charset is specified, the parameter will be encoded according to RFC 579 2231. Optional language specifies the RFC 2231 language, defaulting 580 to the empty string. Both charset and language should be strings. 581 """ 582 if not isinstance(value, tuple) and charset: 583 value = (charset, language, value) 584 585 if not self.has_key(header) and header.lower() == 'content-type': 586 ctype = 'text/plain' 587 else: 588 ctype = self.get(header) 589 if not self.get_param(param, header=header): 590 if not ctype: 591 ctype = _formatparam(param, value, requote) 592 else: 593 ctype = SEMISPACE.join( 594 [ctype, _formatparam(param, value, requote)]) 595 else: 596 ctype = '' 597 for old_param, old_value in self.get_params(header=header, 598 unquote=requote): 599 append_param = '' 600 if old_param.lower() == param.lower(): 601 append_param = _formatparam(param, value, requote) 602 else: 603 append_param = _formatparam(old_param, old_value, requote) 604 if not ctype: 605 ctype = append_param 606 else: 607 ctype = SEMISPACE.join([ctype, append_param]) 608 if ctype != self.get(header): 609 del self[header] 610 self[header] = ctype 611 612 def del_param(self, param, header='content-type', requote=True): 613 """Remove the given parameter completely from the Content-Type header. 614 615 The header will be re-written in place without the parameter or its 616 value. All values will be quoted as necessary unless requote is 617 False. Optional header specifies an alternative to the Content-Type 618 header. 619 """ 620 if not self.has_key(header): 621 return 622 new_ctype = '' 623 for p, v in self.get_params(header=header, unquote=requote): 624 if p.lower() != param.lower(): 625 if not new_ctype: 626 new_ctype = _formatparam(p, v, requote) 627 else: 628 new_ctype = SEMISPACE.join([new_ctype, 629 _formatparam(p, v, requote)]) 630 if new_ctype != self.get(header): 631 del self[header] 632 self[header] = new_ctype 633 634 def set_type(self, type, header='Content-Type', requote=True): 635 """Set the main type and subtype for the Content-Type header. 636 637 type must be a string in the form "maintype/subtype", otherwise a 638 ValueError is raised. 639 640 This method replaces the Content-Type header, keeping all the 641 parameters in place. If requote is False, this leaves the existing 642 header's quoting as is. Otherwise, the parameters will be quoted (the 643 default). 644 645 An alternative header can be specified in the header argument. When 646 the Content-Type header is set, we'll always also add a MIME-Version 647 header. 648 """ 649 # BAW: should we be strict? 650 if not type.count('/') == 1: 651 raise ValueError 652 # Set the Content-Type, you get a MIME-Version 653 if header.lower() == 'content-type': 654 del self['mime-version'] 655 self['MIME-Version'] = '1.0' 656 if not self.has_key(header): 657 self[header] = type 658 return 659 params = self.get_params(header=header, unquote=requote) 660 del self[header] 661 self[header] = type 662 # Skip the first param; it's the old type. 663 for p, v in params[1:]: 664 self.set_param(p, v, header, requote) 665 666 def get_filename(self, failobj=None): 667 """Return the filename associated with the payload if present. 668 669 The filename is extracted from the Content-Disposition header's 670 `filename' parameter, and it is unquoted. If that header is missing 671 the `filename' parameter, this method falls back to looking for the 672 `name' parameter. 673 """ 674 missing = object() 675 filename = self.get_param('filename', missing, 'content-disposition') 676 if filename is missing: 677 filename = self.get_param('name', missing, 'content-disposition') 678 if filename is missing: 679 return failobj 680 return utils.collapse_rfc2231_value(filename).strip() 681 682 def get_boundary(self, failobj=None): 683 """Return the boundary associated with the payload if present. 684 685 The boundary is extracted from the Content-Type header's `boundary' 686 parameter, and it is unquoted. 687 """ 688 missing = object() 689 boundary = self.get_param('boundary', missing) 690 if boundary is missing: 691 return failobj 692 # RFC 2046 says that boundaries may begin but not end in w/s 693 return utils.collapse_rfc2231_value(boundary).rstrip() 694 695 def set_boundary(self, boundary): 696 """Set the boundary parameter in Content-Type to 'boundary'. 697 698 This is subtly different than deleting the Content-Type header and 699 adding a new one with a new boundary parameter via add_header(). The 700 main difference is that using the set_boundary() method preserves the 701 order of the Content-Type header in the original message. 702 703 HeaderParseError is raised if the message has no Content-Type header. 704 """ 705 missing = object() 706 params = self._get_params_preserve(missing, 'content-type') 707 if params is missing: 708 # There was no Content-Type header, and we don't know what type 709 # to set it to, so raise an exception. 710 raise errors.HeaderParseError('No Content-Type header found') 711 newparams = [] 712 foundp = False 713 for pk, pv in params: 714 if pk.lower() == 'boundary': 715 newparams.append(('boundary', '"%s"' % boundary)) 716 foundp = True 717 else: 718 newparams.append((pk, pv)) 719 if not foundp: 720 # The original Content-Type header had no boundary attribute. 721 # Tack one on the end. BAW: should we raise an exception 722 # instead??? 723 newparams.append(('boundary', '"%s"' % boundary)) 724 # Replace the existing Content-Type header with the new value 725 newheaders = [] 726 for h, v in self._headers: 727 if h.lower() == 'content-type': 728 parts = [] 729 for k, v in newparams: 730 if v == '': 731 parts.append(k) 732 else: 733 parts.append('%s=%s' % (k, v)) 734 newheaders.append((h, SEMISPACE.join(parts))) 735 736 else: 737 newheaders.append((h, v)) 738 self._headers = newheaders 739 740 def get_content_charset(self, failobj=None): 741 """Return the charset parameter of the Content-Type header. 742 743 The returned string is always coerced to lower case. If there is no 744 Content-Type header, or if that header has no charset parameter, 745 failobj is returned. 746 """ 747 missing = object() 748 charset = self.get_param('charset', missing) 749 if charset is missing: 750 return failobj 751 if isinstance(charset, tuple): 752 # RFC 2231 encoded, so decode it, and it better end up as ascii. 753 pcharset = charset[0] or 'us-ascii' 754 try: 755 # LookupError will be raised if the charset isn't known to 756 # Python. UnicodeError will be raised if the encoded text 757 # contains a character not in the charset. 758 charset = unicode(charset[2], pcharset).encode('us-ascii') 759 except (LookupError, UnicodeError): 760 charset = charset[2] 761 # charset character must be in us-ascii range 762 try: 763 if isinstance(charset, str): 764 charset = unicode(charset, 'us-ascii') 765 charset = charset.encode('us-ascii') 766 except UnicodeError: 767 return failobj 768 # RFC 2046, $4.1.2 says charsets are not case sensitive 769 return charset.lower() 770 771 def get_charsets(self, failobj=None): 772 """Return a list containing the charset(s) used in this message. 773 774 The returned list of items describes the Content-Type headers' 775 charset parameter for this message and all the subparts in its 776 payload. 777 778 Each item will either be a string (the value of the charset parameter 779 in the Content-Type header of that part) or the value of the 780 'failobj' parameter (defaults to None), if the part does not have a 781 main MIME type of "text", or the charset is not defined. 782 783 The list will contain one string for each part of the message, plus 784 one for the container message (i.e. self), so that a non-multipart 785 message will still return a list of length 1. 786 """ 787 return [part.get_content_charset(failobj) for part in self.walk()] 788 789 # I.e. def walk(self): ... 790 from email.iterators import walk