#!/usr/bin/python3 """ =============================================================================== [September 19, 2013] Fix a backward-incompatible Python 3.3 library change that broke email address displays for non-ASCII names in the PyMailGUI email client, presented in the book Programming Python, 4th Edition (PP4E). This patch is compatible with all Python 3.X, through version 3.3. TO APPLY THIS PATCH: 1) Add this file to the PyMailGUI folder, located in the book's examples tree at PP4E\Internet\Email\PyMailGui. 2) Add an import of this file at the top of either the system's common SharedNames.py, or its main/top-level file PyMailGui.py, both located in the same PyMailGUI folder; or simply copy and use the updated SharedNames.py file included with this patch: # python 3.3+ hack (formataddr change) import py33patch THE BOOK CONTEXT (PP4E): Pages 935-937 trace the steps that PyMaiGUI takes to extract email addresses for display, applying MIME and Unicode decoding. In PyMailGUI code, this spans from Chapter 14's ViewWindow class to Chapter 13's mailParser module. This process is emulated in the self-test code below. Only the last step--the email package's utils.formataddr, which puts name/addr pairs back together--has changed in 3.3, but is sufficient to cause the PyMailGUI breakage. THE PYTHON CHANGE AND FIX: Python 3.3+'s email.utils.formataddr now automatically MIME encodes non-ASCII names in address pairs. For some reason, 3.3 did not make this new and very different behavior an optional feature disabled by default; did not provide a clear mechanism for disabling it at all; and didn't even document the incompatible change for current email users. The most straightforward fix seems to be to copy and install the 3.2 and earlier version of this function, which this file does. This technique is error-prone in general, but requires no other changes, and is backward compatible with all prior 3.X releases. ON BATTERY DEPENDENCY: 3.3+'s email package may assume you'll use a different headers API altogether. But carelessly breaking the existing API with no regard to impacts on its real-world users seems just plain rude. PyMailGUI has long used this utility for display, not for send headers, which it MIME-encodes manually when needed. For the record, the general PyMailGUI use case has been noted explicitly to Python and email package developers in the past. It's unfortunate when incompatible Python change occurs not only in the absence of end-user data, but in defiance of it. =============================================================================== """ import email.utils from email.utils import specialsre, escapesre def py32_formataddr(pair): """ HACK: Copied from 3.2 standard lib: 3.3 auto MIME-encodes non-ASCII names, and offers no way to disable this new/differing functionality; The inverse of parseaddr(), this takes a 2-tuple of the form (realname, email_address) and returns the string value suitable for an RFC 2822 From, To or Cc header. If the first element of pair is false, then the second element is returned unmodified. """ name, address = pair if name: quotes = '' if specialsre.search(name): quotes = '"' name = escapesre.sub(r'\\\g<0>', name) return '%s%s%s <%s>' % (quotes, name, quotes, address) return address # HACK: on import, reset library to prior behavior for this process email.utils.formataddr = py32_formataddr #============================================================================== # SELF-TEST if run: output (below) should be same in 3.0 through 3.3. # Emulates what pymailgui does to display address headers in fetched emails. # Best run/viewed in a Unicode-friendly GUI like IDLE (else see print() redef). #============================================================================== if __name__ == '__main__': from pprint import pprint from email.header import decode_header from email.utils import getaddresses, formataddr """ def print(x): import builtins builtins.print(ascii(x)) # use me if unicode errors at your console """ # from a couple spams: utf-8 unicode, quoted/base64 mime rawheader = ('=?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?= <firstname.lastname@example.org>, ' + '=?utf-8?b?5reY5a6d5Lqk5piT?= <email@example.com>') pairs = getaddresses([rawheader]) # split to name/addr pairs pprint(pairs) addrs =  for (name, addr) in pairs: print('\n' + name) abytes, aenc = decode_header(name) # MIME decode name (single part) print(abytes) name = abytes.decode(aenc) # Unicode decode name (to str) print(name) joined = formataddr((name, addr)) # join name/addr=>3.3 change! print(joined) addrs.append(joined) # one or more addrs print('\n' + ', '.join(addrs)) # combine decoded addrs #============================================================================== # EXPECTED OUTPUT if run directly. # Note: this file doesn't require line2 = "# -*- coding: utf-8 -*-" for the # non-ASCIIs in expected output stings, because utf-8 is the Python default # for source file ecoding, and this is the encoding in which this file was created. #============================================================================== # CORRECT output with patch, 3.0 through 3.3 """ [('=?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?=', 'firstname.lastname@example.org'), ('=?utf-8?b?5reY5a6d5Lqk5piT?=', 'email@example.com')] =?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?= b'Promo\xc3\xa7\xc3\xa3o Cielo' Promoção Cielo Promoção Cielo <firstname.lastname@example.org> =?utf-8?b?5reY5a6d5Lqk5piT?= b'\xe6\xb7\x98\xe5\xae\x9d\xe4\xba\xa4\xe6\x98\x93' 淘宝交易 淘宝交易 <email@example.com> Promoção Cielo <firstname.lastname@example.org>, 淘宝交易 <email@example.com> """ # ERROR output in 3.3 only, if disable (#-out) email.utils.formataddr reset above """ [('=?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?=', 'firstname.lastname@example.org'), ('=?utf-8?b?5reY5a6d5Lqk5piT?=', 'email@example.com')] =?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?= b'Promo\xc3\xa7\xc3\xa3o Cielo' Promoção Cielo =?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?= <firstname.lastname@example.org> =?utf-8?b?5reY5a6d5Lqk5piT?= b'\xe6\xb7\x98\xe5\xae\x9d\xe4\xba\xa4\xe6\x98\x93' 淘宝交易 =?utf-8?b?5reY5a6d5Lqk5piT?= <email@example.com> =?utf-8?q?Promo=C3=A7=C3=A3o_Cielo?= <firstname.lastname@example.org>, =?utf-8?b?5reY5a6d5Lqk5piT?= <email@example.com> """