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# Source Generated with Decompyle++ # File: in.pyc (Python 2.6) '''Header encoding and decoding functionality.''' __all__ = [ 'Header', 'decode_header', 'make_header'] import re import binascii import email.quoprimime as email import email.base64mime as email from email.errors import HeaderParseError from email.charset import Charset NL = '\n' SPACE = ' ' USPACE = u' ' SPACE8 = ' ' * 8 UEMPTYSTRING = u'' MAXLINELEN = 76 USASCII = Charset('us-ascii') UTF8 = Charset('utf-8') ecre = re.compile('\n =\\? # literal =?\n (?P<charset>[^?]*?) # non-greedy up to the next ? is the charset\n \\? # literal ?\n (?P<encoding>[qb]) # either a "q" or a "b", case insensitive\n \\? # literal ?\n (?P<encoded>.*?) # non-greedy up to the next ?= is the encoded string\n \\?= # literal ?=\n (?=[ \\t]|$) # whitespace or the end of the string\n ', re.VERBOSE | re.IGNORECASE | re.MULTILINE) fcre = re.compile('[\\041-\\176]+:$') _max_append = email.quoprimime._max_append def decode_header(header): '''Decode a message header value without converting charset. Returns a list of (decoded_string, charset) pairs containing each of the decoded parts of the header. Charset is None for non-encoded parts of the header, otherwise a lower-case string containing the name of the character set specified in the encoded string. An email.errors.HeaderParseError may be raised when certain decoding error occurs (e.g. a base64 decoding exception). ''' header = str(header) if not ecre.search(header): return [ (header, None)] decoded = [] dec = '' for line in header.splitlines(): if not ecre.search(line): decoded.append((line, None)) continue parts = ecre.split(line) while parts: unenc = parts.pop(0).strip() if unenc: if decoded and decoded[-1][1] is None: decoded[-1] = (decoded[-1][0] + SPACE + unenc, None) else: decoded.append((unenc, None)) if parts: (charset, encoding) = [ s.lower() for s in parts[0:2] ] encoded = parts[2] dec = None if encoding == 'q': dec = email.quoprimime.header_decode(encoded) elif encoding == 'b': try: dec = email.base64mime.decode(encoded) except binascii.Error: [] [] raise HeaderParseError except: []<EXCEPTION MATCH>binascii.Error [] if dec is None: dec = encoded if decoded and decoded[-1][1] == charset: decoded[-1] = (decoded[-1][0] + dec, decoded[-1][1]) else: decoded.append((dec, charset)) del parts[0:3] return decoded def make_header(decoded_seq, maxlinelen = None, header_name = None, continuation_ws = ' '): '''Create a Header from a sequence of pairs as returned by decode_header() decode_header() takes a header value string and returns a sequence of pairs of the format (decoded_string, charset) where charset is the string name of the character set. This function takes one of those sequence of pairs and returns a Header instance. Optional maxlinelen, header_name, and continuation_ws are as in the Header constructor. ''' h = Header(maxlinelen = maxlinelen, header_name = header_name, continuation_ws = continuation_ws) for s, charset in decoded_seq: if charset is not None and not isinstance(charset, Charset): charset = Charset(charset) h.append(s, charset) return h class Header: def __init__(self, s = None, charset = None, maxlinelen = None, header_name = None, continuation_ws = ' ', errors = 'strict'): """Create a MIME-compliant header that can contain many character sets. Optional s is the initial header value. If None, the initial header value is not set. You can later append to the header with .append() method calls. s may be a byte string or a Unicode string, but see the .append() documentation for semantics. Optional charset serves two purposes: it has the same meaning as the charset argument to the .append() method. It also sets the default character set for all subsequent .append() calls that omit the charset argument. If charset is not provided in the constructor, the us-ascii charset is used both as s's initial charset and as the default for subsequent .append() calls. The maximum line length can be specified explicit via maxlinelen. For splitting the first line to a shorter value (to account for the field header which isn't included in s, e.g. `Subject') pass in the name of the field in header_name. The default maxlinelen is 76. continuation_ws must be RFC 2822 compliant folding whitespace (usually either a space or a hard tab) which will be prepended to continuation lines. errors is passed through to the .append() call. """ if charset is None: charset = USASCII if not isinstance(charset, Charset): charset = Charset(charset) self._charset = charset self._continuation_ws = continuation_ws cws_expanded_len = len(continuation_ws.replace('\t', SPACE8)) self._chunks = [] if s is not None: self.append(s, charset, errors) if maxlinelen is None: maxlinelen = MAXLINELEN if header_name is None: self._firstlinelen = maxlinelen else: self._firstlinelen = maxlinelen - len(header_name) - 2 self._maxlinelen = maxlinelen - cws_expanded_len def __str__(self): '''A synonym for self.encode().''' return self.encode() def __unicode__(self): '''Helper for the built-in unicode function.''' uchunks = [] lastcs = None for s, charset in self._chunks: nextcs = charset if uchunks: if lastcs not in (None, 'us-ascii'): if nextcs in (None, 'us-ascii'): uchunks.append(USPACE) nextcs = None elif nextcs not in (None, 'us-ascii'): uchunks.append(USPACE) lastcs = nextcs uchunks.append(unicode(s, str(charset))) return UEMPTYSTRING.join(uchunks) def __eq__(self, other): return other == self.encode() def __ne__(self, other): return not (self == other) def append(self, s, charset = None, errors = 'strict'): """Append a string to the MIME header. Optional charset, if given, should be a Charset instance or the name of a character set (which will be converted to a Charset instance). A value of None (the default) means that the charset given in the constructor is used. s may be a byte string or a Unicode string. If it is a byte string (i.e. isinstance(s, str) is true), then charset is the encoding of that byte string, and a UnicodeError will be raised if the string cannot be decoded with that charset. If s is a Unicode string, then charset is a hint specifying the character set of the characters in the string. In this case, when producing an RFC 2822 compliant header using RFC 2047 rules, the Unicode string will be encoded using the following charsets in order: us-ascii, the charset hint, utf-8. The first character set not to provoke a UnicodeError is used. Optional `errors' is passed as the third argument to any unicode() or ustr.encode() call. """ if charset is None: charset = self._charset elif not isinstance(charset, Charset): charset = Charset(charset) if charset != '8bit': if isinstance(s, str): if not charset.input_codec: pass incodec = 'us-ascii' ustr = unicode(s, incodec, errors) if not charset.output_codec: pass outcodec = 'us-ascii' ustr.encode(outcodec, errors) elif isinstance(s, unicode): for charset in (USASCII, charset, UTF8): try: if not charset.output_codec: pass outcodec = 'us-ascii' s = s.encode(outcodec, errors) continue except UnicodeError: continue elif not False: raise AssertionError, 'utf-8 conversion failed' None<EXCEPTION MATCH>UnicodeError self._chunks.append((s, charset)) def _split(self, s, charset, maxlinelen, splitchars): splittable = charset.to_splittable(s) encoded = charset.from_splittable(splittable, True) elen = charset.encoded_header_len(encoded) if elen <= maxlinelen: return [ (encoded, charset)] if charset == '8bit': return [ (s, charset)] if charset == 'us-ascii': return self._split_ascii(s, charset, maxlinelen, splitchars) fsplittable = charset.to_splittable(first) fencoded = charset.from_splittable(fsplittable, True) chunk = [ (fencoded, charset)] return chunk + self._split(last, charset, self._maxlinelen, splitchars) def _split_ascii(self, s, charset, firstlen, splitchars): chunks = _split_ascii(s, firstlen, self._maxlinelen, self._continuation_ws, splitchars) return zip(chunks, [ charset] * len(chunks)) def _encode_chunks(self, newchunks, maxlinelen): chunks = [] for header, charset in newchunks: if not header: continue if charset is None or charset.header_encoding is None: s = header else: s = charset.header_encode(header) if chunks and chunks[-1].endswith(' '): extra = '' else: extra = ' ' _max_append(chunks, s, maxlinelen, extra) joiner = NL + self._continuation_ws return joiner.join(chunks) def encode(self, splitchars = ';, '): """Encode a message header into an RFC-compliant format. There are many issues involved in converting a given string for use in an email header. Only certain character sets are readable in most email clients, and as header strings can only contain a subset of 7-bit ASCII, care must be taken to properly convert and encode (with Base64 or quoted-printable) header strings. In addition, there is a 75-character length limit on any given encoded header field, so line-wrapping must be performed, even with double-byte character sets. This method will do its best to convert the string to the correct character set used in email, and encode and line wrap it safely with the appropriate scheme for that character set. If the given charset is not known or an error occurs during conversion, this function will return the header untouched. Optional splitchars is a string containing characters to split long ASCII lines on, in rough support of RFC 2822's `highest level syntactic breaks'. This doesn't affect RFC 2047 encoded lines. """ newchunks = [] maxlinelen = self._firstlinelen lastlen = 0 for s, charset in self._chunks: targetlen = maxlinelen - lastlen - 1 if targetlen < charset.encoded_header_len(''): targetlen = maxlinelen newchunks += self._split(s, charset, targetlen, splitchars) (lastchunk, lastcharset) = newchunks[-1] lastlen = lastcharset.encoded_header_len(lastchunk) return self._encode_chunks(newchunks, maxlinelen) def _split_ascii(s, firstlen, restlen, continuation_ws, splitchars): lines = [] maxlen = firstlen for line in s.splitlines(): line = line.lstrip() if len(line) < maxlen: lines.append(line) maxlen = restlen continue for ch in splitchars: if ch in line: break continue else: maxlen = restlen cre = re.compile('%s\\s*' % ch) if ch in ';,': eol = ch else: eol = '' joiner = eol + ' ' joinlen = len(joiner) wslen = len(continuation_ws.replace('\t', SPACE8)) this = [] linelen = 0 for part in cre.split(line): curlen = linelen + max(0, len(this) - 1) * joinlen partlen = len(part) onfirstline = not lines if ch == ' ' and onfirstline and len(this) == 1 and fcre.match(this[0]): this.append(part) linelen += partlen continue if curlen + partlen > maxlen: if this: lines.append(joiner.join(this) + eol) if partlen > maxlen and ch != ' ': subl = _split_ascii(part, maxlen, restlen, continuation_ws, ' ') lines.extend(subl[:-1]) this = [ subl[-1]] else: this = [ part] linelen = wslen + len(this[-1]) maxlen = restlen continue this.append(part) linelen += partlen if this: lines.append(joiner.join(this)) continue return lines def _binsplit(splittable, charset, maxlinelen): i = 0 j = len(splittable) while i < j: m = i + j + 1 >> 1 chunk = charset.from_splittable(splittable[:m], True) chunklen = charset.encoded_header_len(chunk) if chunklen <= maxlinelen: i = m continue j = m - 1 first = charset.from_splittable(splittable[:i], False) last = charset.from_splittable(splittable[i:], False) return (first, last) 
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