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. If value is a 42 three tuple (charset, language, value), it will be encoded according 43 to RFC2231 rules. 44 """ 45 if value is not None and len(value) > 0: 46 # A tuple is used for RFC 2231 encoded parameter values where items 47 # are (charset, language, value). charset is a string, not a Charset 48 # instance. 49 if isinstance(value, tuple): 50 # Encode as per RFC 2231 51 param += '*' 52 value = utils.encode_rfc2231(value[2], value[0], value[1]) 53 # BAW: Please check this. I think that if quote is set it should 54 # force quoting even if not necessary. 55 if quote or tspecials.search(value): 56 return '%s="%s"' % (param, utils.quote(value)) 57 else: 58 return '%s=%s' % (param, value) 59 else: 60 return param 61 62def _parseparam(s): 63 plist = [] 64 while s[:1] == ';': 65 s = s[1:] 66 end = s.find(';') 67 while end > 0 and (s.count('"', 0, end) - s.count('\\"', 0, end)) % 2: 68 end = s.find(';', end + 1) 69 if end < 0: 70 end = len(s) 71 f = s[:end] 72 if '=' in f: 73 i = f.index('=') 74 f = f[:i].strip().lower() + '=' + f[i+1:].strip() 75 plist.append(f.strip()) 76 s = s[end:] 77 return plist 78 79 80def _unquotevalue(value): 81 # This is different than utils.collapse_rfc2231_value() because it doesn't 82 # try to convert the value to a unicode. Message.get_param() and 83 # Message.get_params() are both currently defined to return the tuple in 84 # the face of RFC 2231 parameters. 85 if isinstance(value, tuple): 86 return value[0], value[1], utils.unquote(value[2]) 87 else: 88 return utils.unquote(value) 89 90 91 92class Message: 93 """Basic message object. 94 95 A message object is defined as something that has a bunch of RFC 2822 96 headers and a payload. It may optionally have an envelope header 97 (a.k.a. Unix-From or From_ header). If the message is a container (i.e. a 98 multipart or a message/rfc822), then the payload is a list of Message 99 objects, otherwise it is a string. 100 101 Message objects implement part of the `mapping' interface, which assumes 102 there is exactly one occurrence of the header per message. Some headers 103 do in fact appear multiple times (e.g. Received) and for those headers, 104 you must use the explicit API to set or get all the headers. Not all of 105 the mapping methods are implemented. 106 """ 107 def __init__(self): 108 self._headers = [] 109 self._unixfrom = None 110 self._payload = None 111 self._charset = None 112 # Defaults for multipart messages 113 self.preamble = self.epilogue = None 114 self.defects = [] 115 # Default content type 116 self._default_type = 'text/plain' 117 118 def __str__(self): 119 """Return the entire formatted message as a string. 120 This includes the headers, body, and envelope header. 121 """ 122 return self.as_string(unixfrom=True) 123 124 def as_string(self, unixfrom=False): 125 """Return the entire formatted message as a string. 126 Optional `unixfrom' when True, means include the Unix From_ envelope 127 header. 128 129 This is a convenience method and may not generate the message exactly 130 as you intend because by default it mangles lines that begin with 131 "From ". For more flexibility, use the flatten() method of a 132 Generator instance. 133 """ 134 from email.generator import Generator 135 fp = StringIO() 136 g = Generator(fp) 137 g.flatten(self, unixfrom=unixfrom) 138 return fp.getvalue() 139 140 def is_multipart(self): 141 """Return True if the message consists of multiple parts.""" 142 return isinstance(self._payload, list) 143 144 # 145 # Unix From_ line 146 # 147 def set_unixfrom(self, unixfrom): 148 self._unixfrom = unixfrom 149 150 def get_unixfrom(self): 151 return self._unixfrom 152 153 # 154 # Payload manipulation. 155 # 156 def attach(self, payload): 157 """Add the given payload to the current payload. 158 159 The current payload will always be a list of objects after this method 160 is called. If you want to set the payload to a scalar object, use 161 set_payload() instead. 162 """ 163 if self._payload is None: 164 self._payload = [payload] 165 else: 166 self._payload.append(payload) 167 168 def get_payload(self, i=None, decode=False): 169 """Return a reference to the payload. 170 171 The payload will either be a list object or a string. If you mutate 172 the list object, you modify the message's payload in place. Optional 173 i returns that index into the payload. 174 175 Optional decode is a flag indicating whether the payload should be 176 decoded or not, according to the Content-Transfer-Encoding header 177 (default is False). 178 179 When True and the message is not a multipart, the payload will be 180 decoded if this header's value is `quoted-printable' or `base64'. If 181 some other encoding is used, or the header is missing, or if the 182 payload has bogus data (i.e. bogus base64 or uuencoded data), the 183 payload is returned as-is. 184 185 If the message is a multipart and the decode flag is True, then None 186 is returned. 187 """ 188 if i is None: 189 payload = self._payload 190 elif not isinstance(self._payload, list): 191 raise TypeError('Expected list, got %s' % type(self._payload)) 192 else: 193 payload = self._payload[i] 194 if decode: 195 if self.is_multipart(): 196 return None 197 cte = self.get('content-transfer-encoding', '').lower() 198 if cte == 'quoted-printable': 199 return utils._qdecode(payload) 200 elif cte == 'base64': 201 try: 202 return utils._bdecode(payload) 203 except binascii.Error: 204 # Incorrect padding 205 return payload 206 elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'): 207 sfp = StringIO() 208 try: 209 uu.decode(StringIO(payload+'\n'), sfp, quiet=True) 210 payload = sfp.getvalue() 211 except uu.Error: 212 # Some decoding problem 213 return payload 214 # Everything else, including encodings with 8bit or 7bit are returned 215 # unchanged. 216 return payload 217 218 def set_payload(self, payload, charset=None): 219 """Set the payload to the given value. 220 221 Optional charset sets the message's default character set. See 222 set_charset() for details. 223 """ 224 self._payload = payload 225 if charset is not None: 226 self.set_charset(charset) 227 228 def set_charset(self, charset): 229 """Set the charset of the payload to a given character set. 230 231 charset can be a Charset instance, a string naming a character set, or 232 None. If it is a string it will be converted to a Charset instance. 233 If charset is None, the charset parameter will be removed from the 234 Content-Type field. Anything else will generate a TypeError. 235 236 The message will be assumed to be of type text/* encoded with 237 charset.input_charset. It will be converted to charset.output_charset 238 and encoded properly, if needed, when generating the plain text 239 representation of the message. MIME headers (MIME-Version, 240 Content-Type, Content-Transfer-Encoding) will be added as needed. 241 242 """ 243 if charset is None: 244 self.del_param('charset') 245 self._charset = None 246 return 247 if isinstance(charset, basestring): 248 charset = email.charset.Charset(charset) 249 if not isinstance(charset, email.charset.Charset): 250 raise TypeError(charset) 251 # BAW: should we accept strings that can serve as arguments to the 252 # Charset constructor? 253 self._charset = charset 254 if 'MIME-Version' not in self: 255 self.add_header('MIME-Version', '1.0') 256 if 'Content-Type' not in self: 257 self.add_header('Content-Type', 'text/plain', 258 charset=charset.get_output_charset()) 259 else: 260 self.set_param('charset', charset.get_output_charset()) 261 if isinstance(self._payload, unicode): 262 self._payload = self._payload.encode(charset.output_charset) 263 if str(charset) != charset.get_output_charset(): 264 self._payload = charset.body_encode(self._payload) 265 if 'Content-Transfer-Encoding' not in self: 266 cte = charset.get_body_encoding() 267 try: 268 cte(self) 269 except TypeError: 270 self._payload = charset.body_encode(self._payload) 271 self.add_header('Content-Transfer-Encoding', cte) 272 273 def get_charset(self): 274 """Return the Charset instance associated with the message's payload. 275 """ 276 return self._charset 277 278 # 279 # MAPPING INTERFACE (partial) 280 # 281 def __len__(self): 282 """Return the total number of headers, including duplicates.""" 283 return len(self._headers) 284 285 def __getitem__(self, name): 286 """Get a header value. 287 288 Return None if the header is missing instead of raising an exception. 289 290 Note that if the header appeared multiple times, exactly which 291 occurrence gets returned is undefined. Use get_all() to get all 292 the values matching a header field name. 293 """ 294 return self.get(name) 295 296 def __setitem__(self, name, val): 297 """Set the value of a header. 298 299 Note: this does not overwrite an existing header with the same field 300 name. Use __delitem__() first to delete any existing headers. 301 """ 302 self._headers.append((name, val)) 303 304 def __delitem__(self, name): 305 """Delete all occurrences of a header, if present. 306 307 Does not raise an exception if the header is missing. 308 """ 309 name = name.lower() 310 newheaders = [] 311 for k, v in self._headers: 312 if k.lower() != name: 313 newheaders.append((k, v)) 314 self._headers = newheaders 315 316 def __contains__(self, name): 317 return name.lower() in [k.lower() for k, v in self._headers] 318 319 def has_key(self, name): 320 """Return true if the message contains the header.""" 321 missing = object() 322 return self.get(name, missing) is not missing 323 324 def keys(self): 325 """Return a list of all the message's header field names. 326 327 These will be sorted in the order they appeared in the original 328 message, or were added to the message, and may contain duplicates. 329 Any fields deleted and re-inserted are always appended to the header 330 list. 331 """ 332 return [k for k, v in self._headers] 333 334 def values(self): 335 """Return a list of all the message's header values. 336 337 These will be sorted in the order they appeared in the original 338 message, or were added to the message, and may contain duplicates. 339 Any fields deleted and re-inserted are always appended to the header 340 list. 341 """ 342 return [v for k, v in self._headers] 343 344 def items(self): 345 """Get all the message's header fields and values. 346 347 These will be sorted in the order they appeared in the original 348 message, or were added to the message, and may contain duplicates. 349 Any fields deleted and re-inserted are always appended to the header 350 list. 351 """ 352 return self._headers[:] 353 354 def get(self, name, failobj=None): 355 """Get a header value. 356 357 Like __getitem__() but return failobj instead of None when the field 358 is missing. 359 """ 360 name = name.lower() 361 for k, v in self._headers: 362 if k.lower() == name: 363 return v 364 return failobj 365 366 # 367 # Additional useful stuff 368 # 369 370 def get_all(self, name, failobj=None): 371 """Return a list of all the values for the named field. 372 373 These will be sorted in the order they appeared in the original 374 message, and may contain duplicates. Any fields deleted and 375 re-inserted are always appended to the header list. 376 377 If no such fields exist, failobj is returned (defaults to None). 378 """ 379 values = [] 380 name = name.lower() 381 for k, v in self._headers: 382 if k.lower() == name: 383 values.append(v) 384 if not values: 385 return failobj 386 return values 387 388 def add_header(self, _name, _value, **_params): 389 """Extended header setting. 390 391 name is the header field to add. keyword arguments can be used to set 392 additional parameters for the header field, with underscores converted 393 to dashes. Normally the parameter will be added as key="value" unless 394 value is None, in which case only the key will be added. If a 395 parameter value contains non-ASCII characters it must be specified as a 396 three-tuple of (charset, language, value), in which case it will be 397 encoded according to RFC2231 rules. 398 399 Example: 400 401 msg.add_header('content-disposition', 'attachment', filename='bud.gif') 402 """ 403 parts = [] 404 for k, v in _params.items(): 405 if v is None: 406 parts.append(k.replace('_', '-')) 407 else: 408 parts.append(_formatparam(k.replace('_', '-'), v)) 409 if _value is not None: 410 parts.insert(0, _value) 411 self._headers.append((_name, SEMISPACE.join(parts))) 412 413 def replace_header(self, _name, _value): 414 """Replace a header. 415 416 Replace the first matching header found in the message, retaining 417 header order and case. If no matching header was found, a KeyError is 418 raised. 419 """ 420 _name = _name.lower() 421 for i, (k, v) in zip(range(len(self._headers)), self._headers): 422 if k.lower() == _name: 423 self._headers[i] = (k, _value) 424 break 425 else: 426 raise KeyError(_name) 427 428 # 429 # Use these three methods instead of the three above. 430 # 431 432 def get_content_type(self): 433 """Return the message's content type. 434 435 The returned string is coerced to lower case of the form 436 `maintype/subtype'. If there was no Content-Type header in the 437 message, the default type as given by get_default_type() will be 438 returned. Since according to RFC 2045, messages always have a default 439 type this will always return a value. 440 441 RFC 2045 defines a message's default type to be text/plain unless it 442 appears inside a multipart/digest container, in which case it would be 443 message/rfc822. 444 """ 445 missing = object() 446 value = self.get('content-type', missing) 447 if value is missing: 448 # This should have no parameters 449 return self.get_default_type() 450 ctype = _splitparam(value)[0].lower() 451 # RFC 2045, section 5.2 says if its invalid, use text/plain 452 if ctype.count('/') != 1: 453 return 'text/plain' 454 return ctype 455 456 def get_content_maintype(self): 457 """Return the message's main content type. 458 459 This is the `maintype' part of the string returned by 460 get_content_type(). 461 """ 462 ctype = self.get_content_type() 463 return ctype.split('/')[0] 464 465 def get_content_subtype(self): 466 """Returns the message's sub-content type. 467 468 This is the `subtype' part of the string returned by 469 get_content_type(). 470 """ 471 ctype = self.get_content_type() 472 return ctype.split('/')[1] 473 474 def get_default_type(self): 475 """Return the `default' content type. 476 477 Most messages have a default content type of text/plain, except for 478 messages that are subparts of multipart/digest containers. Such 479 subparts have a default content type of message/rfc822. 480 """ 481 return self._default_type 482 483 def set_default_type(self, ctype): 484 """Set the `default' content type. 485 486 ctype should be either "text/plain" or "message/rfc822", although this 487 is not enforced. The default content type is not stored in the 488 Content-Type header. 489 """ 490 self._default_type = ctype 491 492 def _get_params_preserve(self, failobj, header): 493 # Like get_params() but preserves the quoting of values. BAW: 494 # should this be part of the public interface? 495 missing = object() 496 value = self.get(header, missing) 497 if value is missing: 498 return failobj 499 params = [] 500 for p in _parseparam(';' + value): 501 try: 502 name, val = p.split('=', 1) 503 name = name.strip() 504 val = val.strip() 505 except ValueError: 506 # Must have been a bare attribute 507 name = p.strip() 508 val = '' 509 params.append((name, val)) 510 params = utils.decode_params(params) 511 return params 512 513 def get_params(self, failobj=None, header='content-type', unquote=True): 514 """Return the message's Content-Type parameters, as a list. 515 516 The elements of the returned list are 2-tuples of key/value pairs, as 517 split on the `=' sign. The left hand side of the `=' is the key, 518 while the right hand side is the value. If there is no `=' sign in 519 the parameter the value is the empty string. The value is as 520 described in the get_param() method. 521 522 Optional failobj is the object to return if there is no Content-Type 523 header. Optional header is the header to search instead of 524 Content-Type. If unquote is True, the value is unquoted. 525 """ 526 missing = object() 527 params = self._get_params_preserve(missing, header) 528 if params is missing: 529 return failobj 530 if unquote: 531 return [(k, _unquotevalue(v)) for k, v in params] 532 else: 533 return params 534 535 def get_param(self, param, failobj=None, header='content-type', 536 unquote=True): 537 """Return the parameter value if found in the Content-Type header. 538 539 Optional failobj is the object to return if there is no Content-Type 540 header, or the Content-Type header has no such parameter. Optional 541 header is the header to search instead of Content-Type. 542 543 Parameter keys are always compared case insensitively. The return 544 value can either be a string, or a 3-tuple if the parameter was RFC 545 2231 encoded. When it's a 3-tuple, the elements of the value are of 546 the form (CHARSET, LANGUAGE, VALUE). Note that both CHARSET and 547 LANGUAGE can be None, in which case you should consider VALUE to be 548 encoded in the us-ascii charset. You can usually ignore LANGUAGE. 549 550 Your application should be prepared to deal with 3-tuple return 551 values, and can convert the parameter to a Unicode string like so: 552 553 param = msg.get_param('foo') 554 if isinstance(param, tuple): 555 param = unicode(param[2], param[0] or 'us-ascii') 556 557 In any case, the parameter value (either the returned string, or the 558 VALUE item in the 3-tuple) is always unquoted, unless unquote is set 559 to False. 560 """ 561 if header not in self: 562 return failobj 563 for k, v in self._get_params_preserve(failobj, header): 564 if k.lower() == param.lower(): 565 if unquote: 566 return _unquotevalue(v) 567 else: 568 return v 569 return failobj 570 571 def set_param(self, param, value, header='Content-Type', requote=True, 572 charset=None, language=''): 573 """Set a parameter in the Content-Type header. 574 575 If the parameter already exists in the header, its value will be 576 replaced with the new value. 577 578 If header is Content-Type and has not yet been defined for this 579 message, it will be set to "text/plain" and the new parameter and 580 value will be appended as per RFC 2045. 581 582 An alternate header can specified in the header argument, and all 583 parameters will be quoted as necessary unless requote is False. 584 585 If charset is specified, the parameter will be encoded according to RFC 586 2231. Optional language specifies the RFC 2231 language, defaulting 587 to the empty string. Both charset and language should be strings. 588 """ 589 if not isinstance(value, tuple) and charset: 590 value = (charset, language, value) 591 592 if header not in self and header.lower() == 'content-type': 593 ctype = 'text/plain' 594 else: 595 ctype = self.get(header) 596 if not self.get_param(param, header=header): 597 if not ctype: 598 ctype = _formatparam(param, value, requote) 599 else: 600 ctype = SEMISPACE.join( 601 [ctype, _formatparam(param, value, requote)]) 602 else: 603 ctype = '' 604 for old_param, old_value in self.get_params(header=header, 605 unquote=requote): 606 append_param = '' 607 if old_param.lower() == param.lower(): 608 append_param = _formatparam(param, value, requote) 609 else: 610 append_param = _formatparam(old_param, old_value, requote) 611 if not ctype: 612 ctype = append_param 613 else: 614 ctype = SEMISPACE.join([ctype, append_param]) 615 if ctype != self.get(header): 616 del self[header] 617 self[header] = ctype 618 619 def del_param(self, param, header='content-type', requote=True): 620 """Remove the given parameter completely from the Content-Type header. 621 622 The header will be re-written in place without the parameter or its 623 value. All values will be quoted as necessary unless requote is 624 False. Optional header specifies an alternative to the Content-Type 625 header. 626 """ 627 if header not in self: 628 return 629 new_ctype = '' 630 for p, v in self.get_params(header=header, unquote=requote): 631 if p.lower() != param.lower(): 632 if not new_ctype: 633 new_ctype = _formatparam(p, v, requote) 634 else: 635 new_ctype = SEMISPACE.join([new_ctype, 636 _formatparam(p, v, requote)]) 637 if new_ctype != self.get(header): 638 del self[header] 639 self[header] = new_ctype 640 641 def set_type(self, type, header='Content-Type', requote=True): 642 """Set the main type and subtype for the Content-Type header. 643 644 type must be a string in the form "maintype/subtype", otherwise a 645 ValueError is raised. 646 647 This method replaces the Content-Type header, keeping all the 648 parameters in place. If requote is False, this leaves the existing 649 header's quoting as is. Otherwise, the parameters will be quoted (the 650 default). 651 652 An alternative header can be specified in the header argument. When 653 the Content-Type header is set, we'll always also add a MIME-Version 654 header. 655 """ 656 # BAW: should we be strict? 657 if not type.count('/') == 1: 658 raise ValueError 659 # Set the Content-Type, you get a MIME-Version 660 if header.lower() == 'content-type': 661 del self['mime-version'] 662 self['MIME-Version'] = '1.0' 663 if header not in self: 664 self[header] = type 665 return 666 params = self.get_params(header=header, unquote=requote) 667 del self[header] 668 self[header] = type 669 # Skip the first param; it's the old type. 670 for p, v in params[1:]: 671 self.set_param(p, v, header, requote) 672 673 def get_filename(self, failobj=None): 674 """Return the filename associated with the payload if present. 675 676 The filename is extracted from the Content-Disposition header's 677 `filename' parameter, and it is unquoted. If that header is missing 678 the `filename' parameter, this method falls back to looking for the 679 `name' parameter. 680 """ 681 missing = object() 682 filename = self.get_param('filename', missing, 'content-disposition') 683 if filename is missing: 684 filename = self.get_param('name', missing, 'content-type') 685 if filename is missing: 686 return failobj 687 return utils.collapse_rfc2231_value(filename).strip() 688 689 def get_boundary(self, failobj=None): 690 """Return the boundary associated with the payload if present. 691 692 The boundary is extracted from the Content-Type header's `boundary' 693 parameter, and it is unquoted. 694 """ 695 missing = object() 696 boundary = self.get_param('boundary', missing) 697 if boundary is missing: 698 return failobj 699 # RFC 2046 says that boundaries may begin but not end in w/s 700 return utils.collapse_rfc2231_value(boundary).rstrip() 701 702 def set_boundary(self, boundary): 703 """Set the boundary parameter in Content-Type to 'boundary'. 704 705 This is subtly different than deleting the Content-Type header and 706 adding a new one with a new boundary parameter via add_header(). The 707 main difference is that using the set_boundary() method preserves the 708 order of the Content-Type header in the original message. 709 710 HeaderParseError is raised if the message has no Content-Type header. 711 """ 712 missing = object() 713 params = self._get_params_preserve(missing, 'content-type') 714 if params is missing: 715 # There was no Content-Type header, and we don't know what type 716 # to set it to, so raise an exception. 717 raise errors.HeaderParseError('No Content-Type header found') 718 newparams = [] 719 foundp = False 720 for pk, pv in params: 721 if pk.lower() == 'boundary': 722 newparams.append(('boundary', '"%s"' % boundary)) 723 foundp = True 724 else: 725 newparams.append((pk, pv)) 726 if not foundp: 727 # The original Content-Type header had no boundary attribute. 728 # Tack one on the end. BAW: should we raise an exception 729 # instead??? 730 newparams.append(('boundary', '"%s"' % boundary)) 731 # Replace the existing Content-Type header with the new value 732 newheaders = [] 733 for h, v in self._headers: 734 if h.lower() == 'content-type': 735 parts = [] 736 for k, v in newparams: 737 if v == '': 738 parts.append(k) 739 else: 740 parts.append('%s=%s' % (k, v)) 741 newheaders.append((h, SEMISPACE.join(parts))) 742 743 else: 744 newheaders.append((h, v)) 745 self._headers = newheaders 746 747 def get_content_charset(self, failobj=None): 748 """Return the charset parameter of the Content-Type header. 749 750 The returned string is always coerced to lower case. If there is no 751 Content-Type header, or if that header has no charset parameter, 752 failobj is returned. 753 """ 754 missing = object() 755 charset = self.get_param('charset', missing) 756 if charset is missing: 757 return failobj 758 if isinstance(charset, tuple): 759 # RFC 2231 encoded, so decode it, and it better end up as ascii. 760 pcharset = charset[0] or 'us-ascii' 761 try: 762 # LookupError will be raised if the charset isn't known to 763 # Python. UnicodeError will be raised if the encoded text 764 # contains a character not in the charset. 765 charset = unicode(charset[2], pcharset).encode('us-ascii') 766 except (LookupError, UnicodeError): 767 charset = charset[2] 768 # charset character must be in us-ascii range 769 try: 770 if isinstance(charset, str): 771 charset = unicode(charset, 'us-ascii') 772 charset = charset.encode('us-ascii') 773 except UnicodeError: 774 return failobj 775 # RFC 2046, $4.1.2 says charsets are not case sensitive 776 return charset.lower() 777 778 def get_charsets(self, failobj=None): 779 """Return a list containing the charset(s) used in this message. 780 781 The returned list of items describes the Content-Type headers' 782 charset parameter for this message and all the subparts in its 783 payload. 784 785 Each item will either be a string (the value of the charset parameter 786 in the Content-Type header of that part) or the value of the 787 'failobj' parameter (defaults to None), if the part does not have a 788 main MIME type of "text", or the charset is not defined. 789 790 The list will contain one string for each part of the message, plus 791 one for the container message (i.e. self), so that a non-multipart 792 message will still return a list of length 1. 793 """ 794 return [part.get_content_charset(failobj) for part in self.walk()] 795 796 # I.e. def walk(self): ... 797 from email.iterators import walk 798