email.parser: impossible to read messages encoded in a different encoding

Doc/library/email.rst

 :mod:`email` --- An email and MIME handling package
 ===================================================
 
 .. module:: email
    :synopsis: Package supporting the parsing, manipulating, and generating
               email messages, including MIME documents.
 .. moduleauthor:: Barry A. Warsaw <barry@python.org>
 .. sectionauthor:: Barry A. Warsaw <barry@python.org>
-.. Copyright (C) 2001-2007 Python Software Foundation
+.. Copyright (C) 2001-2010 Python Software Foundation
 
 
 The :mod:`email` package is a library for managing email messages, including
 MIME and other :rfc:`2822`\ -based message documents.  It is specifically *not*
 designed to do any sending of email messages to SMTP (:rfc:`2821`), NNTP, or
 other servers; those are functions of modules such as :mod:`smtplib` and
 :mod:`nntplib`. The :mod:`email` package attempts to be as RFC-compliant as
 possible, supporting in addition to :rfc:`2822`, such MIME-related RFCs as
 :rfc:`2045`, :rfc:`2046`, :rfc:`2047`, and :rfc:`2231`.
 
@@ skipping 65 matching lines @@
 | email version | distributed with             | compatible with       |
 +===============+==============================+=======================+
 | :const:`1.x`  | Python 2.2.0 to Python 2.2.1 | *no longer supported* |
 +---------------+------------------------------+-----------------------+
 | :const:`2.5`  | Python 2.2.2+ and Python 2.3 | Python 2.1 to 2.5     |
 +---------------+------------------------------+-----------------------+
 | :const:`3.0`  | Python 2.4                   | Python 2.3 to 2.5     |
 +---------------+------------------------------+-----------------------+
 | :const:`4.0`  | Python 2.5                   | Python 2.3 to 2.5     |
 +---------------+------------------------------+-----------------------+
+| :const:`5.0`  | Python 3.0 and Python 3.1    | Python 3.0 to 3.2     |
++---------------+------------------------------+-----------------------+
+| :const:`5.1`  | Python 3.2                   | Python 3.0 to 3.2     | 
++---------------+------------------------------+-----------------------+
+
+Here are the major differences between :mod:`email` version 5.1 and
+version 5.0:
+
+* It is once again possible to parse messages containing non-ASCII bytes,
+  and to reproduce such messages if the data containing the non-ASCII
+  bytes is not modified.
+
+* New functions :func:`message_from_bytes` and :func:`message_from_binary_file`,
+  and new classes :class:`~email.parser.BytesFeedparser` and
+  :class:`~email.parser.BytesParser` allow binary message data to be parsed
+  into model objects.
+
+* Given bytes input to the model, :meth:`~email.Message.get_payload()` will
+  by default decode a message body that has a
+  :mailheader:`ContentTransferEncoding` of `8bit` using the charset specified
+  in the MIME headers and return the resulting string.
+
+* :class:`~email.generator.Generator` will convert message bodies that
+  have a :mailheader:`ContentTransferEncoding` of 8bit and a known charset to
+  instead have a :mailheader:`CotnentTransferEncoding` of ``QuotedPrintable``.
+
+* New function :class:`~email.generator.BytesGenerator` produces bytes
+  as output, preserving any unchanged non-ASCII data that was
+  present in the input used to build the model.
+
+Here are the major differences between :mod:`email` version 5 and version 3:
+
+* All operations are on unicode strings.  Text inputs must be strings,
+  text outputs are strings.  Outputs are limited to the ASCII character
+  set and so can be encoded to ASCII for transmission.  Inputs are also
+  limited to ASCII; this is an acknowledged limitation of email 5.0 and
+  means it can only be used to parse email that is 7bit clean.
 
 Here are the major differences between :mod:`email` version 4 and version 3:
 
 * All modules have been renamed according to :pep:`8` standards.  For example,
   the version 3 module :mod:`email.Message` was renamed to :mod:`email.message` in
   version 4.
 
 * A new subpackage :mod:`email.mime` was added and all the version 3
   :mod:`email.MIME\*` modules were renamed and situated into the :mod:`email.mime`
   subpackage.  For example, the version 3 module :mod:`email.MIMEText` was renamed
@@ skipping 202 matching lines @@
 :mod:`date` modules.  All of these functions have been moved to the
 :mod:`email.utils` module.
 
 The ``MsgReader`` class/module has been removed.  Its functionality is most
 closely supported in the :func:`body_line_iterator` function in the
 :mod:`email.iterators` module.
 
 .. rubric:: Footnotes
 
 .. [#] Delivery Status Notifications (DSN) are defined in :rfc:`1894`.