From b97205f9a8e59526f3f8bc8a0c02ae5661206525 Mon Sep 17 00:00:00 2001 From: Antoine Nguyen Date: Mon, 18 May 2015 15:58:17 +0200 Subject: [PATCH] Last commit was too violent! --- modoboa/lib/imap_utf7.py | 214 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 214 insertions(+) create mode 100644 modoboa/lib/imap_utf7.py diff --git a/modoboa/lib/imap_utf7.py b/modoboa/lib/imap_utf7.py new file mode 100644 index 000000000..2da57f0e9 --- /dev/null +++ b/modoboa/lib/imap_utf7.py @@ -0,0 +1,214 @@ +# -*- coding: iso-8859-1 -*- + +""" +Imap folder names are encoded using a special version of utf-7 as +defined in RFC 2060 section 5.1.3. + +5.1.3. Mailbox International Naming Convention + + By convention, international mailbox names are specified using a + modified version of the UTF-7 encoding described in [UTF-7]. The + purpose of these modifications is to correct the following problems + with UTF-7: + + 1) UTF-7 uses the "+" character for shifting; this conflicts with + the common use of "+" in mailbox names, in particular USENET + newsgroup names. + + 2) UTF-7's encoding is BASE64 which uses the "/" character; this + conflicts with the use of "/" as a popular hierarchy delimiter. + + 3) UTF-7 prohibits the unencoded usage of "\"; this conflicts with + the use of "\" as a popular hierarchy delimiter. + + 4) UTF-7 prohibits the unencoded usage of "~"; this conflicts with + the use of "~" in some servers as a home directory indicator. + + 5) UTF-7 permits multiple alternate forms to represent the same + string; in particular, printable US-ASCII chararacters can be + represented in encoded form. + + In modified UTF-7, printable US-ASCII characters except for "&" + represent themselves; that is, characters with octet values 0x20-0x25 + and 0x27-0x7e. The character "&" (0x26) is represented by the two- + octet sequence "&-". + + All other characters (octet values 0x00-0x1f, 0x7f-0xff, and all + Unicode 16-bit octets) are represented in modified BASE64, with a + further modification from [UTF-7] that "," is used instead of "/". + Modified BASE64 MUST NOT be used to represent any printing US-ASCII + character which can represent itself. + + "&" is used to shift to modified BASE64 and "-" to shift back to US- + ASCII. All names start in US-ASCII, and MUST end in US-ASCII (that + is, a name that ends with a Unicode 16-bit octet MUST end with a "- + "). + + For example, here is a mailbox name which mixes English, Japanese, + and Chinese text: ~peter/mail/&ZeVnLIqe-/&U,BTFw- + +Found here: +http://svn.plone.org/svn/collective/mxmImapClient/trunk/imapUTF7.py + +""" +import binascii +import codecs + +# encoding + + +def modified_base64(s): + s = s.encode('utf-16be') + return binascii.b2a_base64(s).rstrip('\n=').replace('/', ',') + + +def doB64(_in, r): + if _in: + r.append('&%s-' % modified_base64(''.join(_in))) + del _in[:] + + +def encoder(s): + r = [] + _in = [] + for c in s: + ordC = ord(c) + if 0x20 <= ordC <= 0x25 or 0x27 <= ordC <= 0x7e: + doB64(_in, r) + r.append(c) + elif c == '&': + doB64(_in, r) + r.append('&-') + else: + _in.append(c) + doB64(_in, r) + return (str(''.join(r)), len(s)) + + +# decoding + +def modified_unbase64(s): + b = binascii.a2b_base64(s.replace(',', '/') + '===') + return unicode(b, 'utf-16be') + + +def decoder(s): + r = [] + decode = [] + for c in s: + if c == '&' and not decode: + decode.append('&') + elif c == '-' and decode: + if len(decode) == 1: + r.append('&') + else: + r.append(modified_unbase64(''.join(decode[1:]))) + decode = [] + elif decode: + decode.append(c) + else: + r.append(c) + if decode: + r.append(modified_unbase64(''.join(decode[1:]))) + bin_str = ''.join(r) + return (bin_str, len(s)) + + +class StreamReader(codecs.StreamReader): + def decode(self, s, errors='strict'): + return decoder(s) + + +class StreamWriter(codecs.StreamWriter): + def decode(self, s, errors='strict'): + return encoder(s) + + +def imap4_utf_7(name): + if name == 'imap4-utf-7': + return (encoder, decoder, StreamReader, StreamWriter) +codecs.register(imap4_utf_7) + + +# testing methods + +def imapUTF7Encode(ust): + "Returns imap utf-7 encoded version of string" + return ust.encode('imap4-utf-7') + + +def imapUTF7EncodeSequence(seq): + "Returns imap utf-7 encoded version of strings in sequence" + return [imapUTF7Encode(itm) for itm in seq] + + +def imapUTF7Decode(st): + "Returns utf7 encoded version of imap utf-7 string" + return st.decode('imap4-utf-7') + + +def imapUTF7DecodeSequence(seq): + "Returns utf7 encoded version of imap utf-7 strings in sequence" + return [imapUTF7Decode(itm) for itm in seq] + + +def utf8Decode(st): + "Returns utf7 encoded version of imap utf-7 string" + return st.decode('utf-8') + + +def utf7SequenceToUTF8(seq): + "Returns utf7 encoded version of imap utf-7 strings in sequence" + return [itm.decode('imap4-utf-7').encode('utf-8') for itm in seq] + + +__all__ = ['imapUTF7Encode', 'imapUTF7Decode', ] + +if __name__ == '__main__': + + # print u'bøx'.encode('imap4-utf-7') + # print 'expected b&APg-x' + + # print u'båx'.encode('imap4-utf-7') + # print 'expected b&AOU-x' + + print '#######' + print 'bøx' + e = imapUTF7Encode(u'bøx') + print e + print imapUTF7Decode(e).encode('latin-1') + + print '#######' + print 'båx' + e = imapUTF7Encode(u'båx') + print e + print imapUTF7Decode(e).encode('latin-1') + + print '#######' + print '~/bågø' + e = imapUTF7Encode(u'~/bågø') + print e + print imapUTF7Decode(e).encode('latin-1') + + print '#######' + print 'Ting & Såger' + e = imapUTF7Encode(u'Ting & Såger') + print e + print imapUTF7Decode(e).encode('latin-1') + + # e = imapUTF7Decode('b&AOU-x') + # print e.encode('latin-1') + + # e = imapUTF7Decode('b&APg-x') + # print e.encode('latin-1') + + print '#######' + print '~/Følder/mailbåx & stuff + more' + n = u'~/Følder/mailbåx & stuff + more' + e = imapUTF7Encode(n) + print e + print imapUTF7Decode(e).encode('latin-1') + + print '#######' + print '~peter/mail/&ZeVnLIqe-/&U,BTFw-' + print imapUTF7Decode('~peter/mail/&ZeVnLIqe-/&U,BTFw-').encode('utf-8')