338 lines
13 KiB
Python
338 lines
13 KiB
Python
# Copyright (C) 2001,2002 Python Software Foundation
|
||
# Author: che@debian.org (Ben Gertzfield)
|
||
|
||
try:
|
||
unicode
|
||
except NameError:
|
||
def _is_unicode(x):
|
||
return 1==0
|
||
else:
|
||
# Use UnicodeType instead of built-in unicode for Py2.1 compatibility
|
||
from types import UnicodeType
|
||
def _is_unicode(x):
|
||
return isinstance(x, UnicodeType)
|
||
|
||
from email.Encoders import encode_7or8bit
|
||
import email.base64MIME
|
||
import email.quopriMIME
|
||
|
||
|
||
|
||
# Flags for types of header encodings
|
||
QP = 1 # Quoted-Printable
|
||
BASE64 = 2 # Base64
|
||
|
||
# In "=?charset?q?hello_world?=", the =?, ?q?, and ?= add up to 7
|
||
MISC_LEN = 7
|
||
|
||
DEFAULT_CHARSET = 'us-ascii'
|
||
|
||
|
||
|
||
# Defaults
|
||
CHARSETS = {
|
||
# input header enc body enc output conv
|
||
'iso-8859-1': (QP, QP, None),
|
||
'iso-8859-2': (QP, QP, None),
|
||
'us-ascii': (None, None, None),
|
||
'big5': (BASE64, BASE64, None),
|
||
'gb2312': (BASE64, BASE64, None),
|
||
'euc-jp': (BASE64, None, 'iso-2022-jp'),
|
||
'shift_jis': (BASE64, None, 'iso-2022-jp'),
|
||
'iso-2022-jp': (BASE64, None, None),
|
||
'koi8-r': (BASE64, BASE64, None),
|
||
'utf-8': (BASE64, BASE64, 'utf-8'),
|
||
}
|
||
|
||
# Aliases for other commonly-used names for character sets. Map
|
||
# them to the real ones used in email.
|
||
ALIASES = {
|
||
'latin_1': 'iso-8859-1',
|
||
'latin-1': 'iso-8859-1',
|
||
'ascii': 'us-ascii',
|
||
}
|
||
|
||
# Map charsets to their Unicode codec strings. Note that the Japanese
|
||
# examples included below do not (yet) come with Python! They are available
|
||
# from http://pseudo.grad.sccs.chukyo-u.ac.jp/~kajiyama/python/
|
||
|
||
# The Chinese and Korean codecs are available from SourceForge:
|
||
#
|
||
# http://sourceforge.net/projects/python-codecs/
|
||
#
|
||
# although you'll need to check them out of cvs since they haven't been file
|
||
# released yet. You might also try to use
|
||
#
|
||
# http://www.freshports.org/port-description.php3?port=6702
|
||
#
|
||
# if you can get logged in. AFAICT, both the Chinese and Korean codecs are
|
||
# fairly experimental at this point.
|
||
CODEC_MAP = {
|
||
'euc-jp': 'japanese.euc-jp',
|
||
'iso-2022-jp': 'japanese.iso-2022-jp',
|
||
'shift_jis': 'japanese.shift_jis',
|
||
'gb2132': 'eucgb2312_cn',
|
||
'big5': 'big5_tw',
|
||
'utf-8': 'utf-8',
|
||
# Hack: We don't want *any* conversion for stuff marked us-ascii, as all
|
||
# sorts of garbage might be sent to us in the guise of 7-bit us-ascii.
|
||
# Let that stuff pass through without conversion to/from Unicode.
|
||
'us-ascii': None,
|
||
}
|
||
|
||
|
||
|
||
# Convenience functions for extending the above mappings
|
||
def add_charset(charset, header_enc=None, body_enc=None, output_charset=None):
|
||
"""Add charset properties to the global map.
|
||
|
||
charset is the input character set, and must be the canonical name of a
|
||
character set.
|
||
|
||
Optional header_enc and body_enc is either Charset.QP for
|
||
quoted-printable, Charset.BASE64 for base64 encoding, or None for no
|
||
encoding. It describes how message headers and message bodies in the
|
||
input charset are to be encoded. Default is no encoding.
|
||
|
||
Optional output_charset is the character set that the output should be
|
||
in. Conversions will proceed from input charset, to Unicode, to the
|
||
output charset when the method Charset.convert() is called. The default
|
||
is to output in the same character set as the input.
|
||
|
||
Both input_charset and output_charset must have Unicode codec entries in
|
||
the module's charset-to-codec mapping; use add_codec(charset, codecname)
|
||
to add codecs the module does not know about. See the codec module's
|
||
documentation for more information.
|
||
"""
|
||
CHARSETS[charset] = (header_enc, body_enc, output_charset)
|
||
|
||
|
||
def add_alias(alias, canonical):
|
||
"""Add a character set alias.
|
||
|
||
alias is the alias name, e.g. latin-1
|
||
canonical is the character set's canonical name, e.g. iso-8859-1
|
||
"""
|
||
ALIASES[alias] = canonical
|
||
|
||
|
||
def add_codec(charset, codecname):
|
||
"""Add a codec that map characters in the given charset to/from Unicode.
|
||
|
||
charset is the canonical name of a character set. codecname is the name
|
||
of a Python codec, as appropriate for the second argument to the unicode()
|
||
built-in, or to the .encode() method of a Unicode string.
|
||
"""
|
||
CODEC_MAP[charset] = codecname
|
||
|
||
|
||
|
||
class Charset:
|
||
"""Map character sets to their email properties.
|
||
|
||
This class provides information about the requirements imposed on email
|
||
for a specific character set. It also provides convenience routines for
|
||
converting between character sets, given the availability of the
|
||
applicable codecs. Given an character set, it will do its best to provide
|
||
information on how to use that character set in an email.
|
||
|
||
Certain character sets must be encoded with quoted-printable or base64
|
||
when used in email headers or bodies. Certain character sets must be
|
||
converted outright, and are not allowed in email. Instances of this
|
||
module expose the following information about a character set:
|
||
|
||
input_charset: The initial character set specified. Common aliases
|
||
are converted to their `official' email names (e.g. latin_1
|
||
is converted to iso-8859-1). Defaults to 7-bit us-ascii.
|
||
|
||
header_encoding: If the character set must be encoded before it can be
|
||
used in an email header, this attribute will be set to
|
||
Charset.QP (for quoted-printable) or Charset.BASE64 (for
|
||
base64 encoding). Otherwise, it will be None.
|
||
|
||
body_encoding: Same as header_encoding, but describes the encoding for the
|
||
mail message's body, which indeed may be different than the
|
||
header encoding.
|
||
|
||
output_charset: Some character sets must be converted before the can be
|
||
used in email headers or bodies. If the input_charset is
|
||
one of them, this attribute will contain the name of the
|
||
charset output will be converted to. Otherwise, it will
|
||
be None.
|
||
|
||
input_codec: The name of the Python codec used to convert the
|
||
input_charset to Unicode. If no conversion codec is
|
||
necessary, this attribute will be None.
|
||
|
||
output_codec: The name of the Python codec used to convert Unicode
|
||
to the output_charset. If no conversion codec is necessary,
|
||
this attribute will have the same value as the input_codec.
|
||
"""
|
||
def __init__(self, input_charset=DEFAULT_CHARSET):
|
||
# Set the input charset after filtering through the aliases
|
||
self.input_charset = ALIASES.get(input_charset, input_charset)
|
||
# We can try to guess which encoding and conversion to use by the
|
||
# charset_map dictionary. Try that first, but let the user override
|
||
# it.
|
||
henc, benc, conv = CHARSETS.get(self.input_charset,
|
||
(BASE64, BASE64, None))
|
||
# Set the attributes, allowing the arguments to override the default.
|
||
self.header_encoding = henc
|
||
self.body_encoding = benc
|
||
self.output_charset = ALIASES.get(conv, conv)
|
||
# Now set the codecs. If one isn't defined for input_charset,
|
||
# guess and try a Unicode codec with the same name as input_codec.
|
||
self.input_codec = CODEC_MAP.get(self.input_charset,
|
||
self.input_charset)
|
||
self.output_codec = CODEC_MAP.get(self.output_charset,
|
||
self.input_codec)
|
||
|
||
def __str__(self):
|
||
return self.input_charset.lower()
|
||
|
||
def __eq__(self, other):
|
||
return str(self) == str(other).lower()
|
||
|
||
def __ne__(self, other):
|
||
return not self.__eq__(other)
|
||
|
||
def get_body_encoding(self):
|
||
"""Return the content-transfer-encoding used for body encoding.
|
||
|
||
This is either the string `quoted-printable' or `base64' depending on
|
||
the encoding used, or it is a function in which case you should call
|
||
the function with a single argument, the Message object being
|
||
encoded. The function should then set the Content-Transfer-Encoding:
|
||
header itself to whatever is appropriate.
|
||
|
||
Returns "quoted-printable" if self.body_encoding is QP.
|
||
Returns "base64" if self.body_encoding is BASE64.
|
||
Returns "7bit" otherwise.
|
||
"""
|
||
if self.body_encoding == QP:
|
||
return 'quoted-printable'
|
||
elif self.body_encoding == BASE64:
|
||
return 'base64'
|
||
else:
|
||
return encode_7or8bit
|
||
|
||
def convert(self, s):
|
||
"""Convert a string from the input_codec to the output_codec."""
|
||
if self.input_codec <> self.output_codec:
|
||
return unicode(s, self.input_codec).encode(self.output_codec)
|
||
else:
|
||
return s
|
||
|
||
def to_splittable(self, s):
|
||
"""Convert a possibly multibyte string to a safely splittable format.
|
||
|
||
Uses the input_codec to try and convert the string to Unicode, so it
|
||
can be safely split on character boundaries (even for double-byte
|
||
characters).
|
||
|
||
Returns the string untouched if we don't know how to convert it to
|
||
Unicode with the input_charset.
|
||
|
||
Characters that could not be converted to Unicode will be replaced
|
||
with the Unicode replacement character U+FFFD.
|
||
"""
|
||
if _is_unicode(s) or self.input_codec is None:
|
||
return s
|
||
try:
|
||
return unicode(s, self.input_codec, 'replace')
|
||
except LookupError:
|
||
# Input codec not installed on system, so return the original
|
||
# string unchanged.
|
||
return s
|
||
|
||
def from_splittable(self, ustr, to_output=1):
|
||
"""Convert a splittable string back into an encoded string.
|
||
|
||
Uses the proper codec to try and convert the string from
|
||
Unicode back into an encoded format. Return the string as-is
|
||
if it is not Unicode, or if it could not be encoded from
|
||
Unicode.
|
||
|
||
Characters that could not be converted from Unicode will be replaced
|
||
with an appropriate character (usually '?').
|
||
|
||
If to_output is true, uses output_codec to convert to an encoded
|
||
format. If to_output is false, uses input_codec. to_output defaults
|
||
to 1.
|
||
"""
|
||
if to_output:
|
||
codec = self.output_codec
|
||
else:
|
||
codec = self.input_codec
|
||
if not _is_unicode(ustr) or codec is None:
|
||
return ustr
|
||
try:
|
||
return ustr.encode(codec, 'replace')
|
||
except LookupError:
|
||
# Output codec not installed
|
||
return ustr
|
||
|
||
def get_output_charset(self):
|
||
"""Return the output character set.
|
||
|
||
This is self.output_charset if that is set, otherwise it is
|
||
self.input_charset.
|
||
"""
|
||
return self.output_charset or self.input_charset
|
||
|
||
def encoded_header_len(self, s):
|
||
"""Return the length of the encoded header string."""
|
||
cset = self.get_output_charset()
|
||
# The len(s) of a 7bit encoding is len(s)
|
||
if self.header_encoding is BASE64:
|
||
return email.base64MIME.base64_len(s) + len(cset) + MISC_LEN
|
||
elif self.header_encoding is QP:
|
||
return email.quopriMIME.header_quopri_len(s) + len(cset) + MISC_LEN
|
||
else:
|
||
return len(s)
|
||
|
||
def header_encode(self, s, convert=0):
|
||
"""Header-encode a string, optionally converting it to output_charset.
|
||
|
||
If convert is true, the string will be converted from the input
|
||
charset to the output charset automatically. This is not useful for
|
||
multibyte character sets, which have line length issues (multibyte
|
||
characters must be split on a character, not a byte boundary); use the
|
||
high-level Header class to deal with these issues. convert defaults
|
||
to 0.
|
||
|
||
The type of encoding (base64 or quoted-printable) will be based on
|
||
self.header_encoding.
|
||
"""
|
||
cset = self.get_output_charset()
|
||
if convert:
|
||
s = self.convert(s)
|
||
# 7bit/8bit encodings return the string unchanged (modulo conversions)
|
||
if self.header_encoding is BASE64:
|
||
return email.base64MIME.header_encode(s, cset)
|
||
elif self.header_encoding is QP:
|
||
return email.quopriMIME.header_encode(s, cset)
|
||
else:
|
||
return s
|
||
|
||
def body_encode(self, s, convert=1):
|
||
"""Body-encode a string and convert it to output_charset.
|
||
|
||
If convert is true (the default), the string will be converted from
|
||
the input charset to output charset automatically. Unlike
|
||
header_encode(), there are no issues with byte boundaries and
|
||
multibyte charsets in email bodies, so this is usually pretty safe.
|
||
|
||
The type of encoding (base64 or quoted-printable) will be based on
|
||
self.body_encoding.
|
||
"""
|
||
if convert:
|
||
s = self.convert(s)
|
||
# 7bit/8bit encodings return the string unchanged (module conversions)
|
||
if self.body_encoding is BASE64:
|
||
return email.base64MIME.body_encode(s)
|
||
elif self.header_encoding is QP:
|
||
return email.quopriMIME.body_encode(s)
|
||
else:
|
||
return s
|