mutt 侧边栏中的希腊字符（通过 Offlineimap 获取的邮箱名称）

Question

简而言之,

“问题”源于以下事实：IMAP4 使用修改后的 UTF-7 编码对文件夹名称进行编码。离线地图在创建本地存储库之前，不会将文件夹名称转换为可读的名称（例如，以 UTF-8 格式）。反过来，这会派生出不可读的文件夹名称，如该问题的屏幕截图中所示的名称。因此，它既不是穆特也不离线地图本身的处理不当或配置错误。

以下博客文章和 git 存储库详细讨论并解决了该问题：

解决方案

本质上，一个蟒蛇脚本（下面提供）有助于导出可读的文件夹名称，被输入到offlineimap的配置文件中（即offlineimaprc，如中所述离线IMAP手册）。此外，还有一行用于正确文件夹名称转换的指导性代码（使用 python 脚本中定义的函数），即

# Name translation from UTF7 to UTF8
nametrans = lambda foldername: foldername.decode('imap4-utf-7').encode('utf-8')

被添加到 offlineimap 配置文件中的远程存储库选项部分下。

更新（2015 年 4 月）

另一个规则是必需的反向操作参见文件夹过滤和名称翻译。该说明可能类似于

# Name translation, reverse!
nametrans = lambda foldername: foldername.decode('utf-8').encode('imap4-utf-7')

在该mailboxes文件中，offlineimap 创建的希腊名称正确显示。这解决了 mutt 内部的问题，并且文件夹名称按预期显示（在本例中为希腊名称）。在此输入图像描述

剩下的问题？

但是，本地存储库文件夹名称（目录名称）仍然处于不可读状态。即，上面显示的希腊文件夹名称（Yποτροφία）实际上是目录&A6UDwAO,A8QDwQO,A8YDrwOx-.这是否意味着文件夹名称转换发生在文件夹名称和消息同步之后而不是同步期间？或者，是否需要删除这些目录（来自本地存储库）并通过 Offlineimap 强制另一次同步（注意不要让相应的邮箱文件夹从远程存储库中删除）？

处理国际邮箱名称（IMAP、UTF-7）的 Python 脚本：

# vim:fileencoding=utf-8

r"""
Imap folder names are encoded using a special version of utf-7 as defined in RFC
2060 section 5.1.3.

From: http://piao-tech.blogspot.com/2010/03/get-offlineimap-working-with-non-ascii.html

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-

"""

import binascii
import codecs

# encoding
def modified_base64(s):
  s = s.encode('utf-16be')
  return binascii.b2a_base64(s).rstrip(b'\n=').replace(b'/', b',').decode('ascii')

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 (''.join(r).encode('ascii'), len(s))

# decoding
def modified_unbase64(s):
  b = binascii.a2b_base64(s.replace(b',', b'/') + b'===')
  return str(b, 'utf-16be')

def decoder(s):
  r = []
  decode = []
  for c in s:
    if c == b'&' and not decode:
      decode.append(b'&')
    elif c == b'-' and decode:
      if len(decode) == 1:
        r.append('&')
      else:
        r.append(modified_unbase64(b''.join(decode[1:])))
      decode = []
    elif decode:
      decode.append(c)
    else:
      r.append(c.decode('ascii'))
  if decode:
    r.append(modified_unbase64(b''.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)

Answer 1