Python运行报错UnicodeDecodeError的解决方法

Python2.7在Windows上有一个bug，运行报错：

    UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 33: ordinal not in range(128)

解决方案如下：

编辑Python27\Lib\mimetypes.py文件，全选，替换为以下patch后的正确脚本，或者直接依据此patch修改：

    """Guess the MIME type of a file.

    This module defines two useful functions:

    guess_type(url, strict=1) -- guess the MIME type and encoding of a URL.

    guess_extension(type, strict=1) -- guess the extension for a given MIME type.

    It also contains the following, for tuning the behavior:

    Data:

    knownfiles -- list of files to parse
    inited -- flag set when init() has been called
    suffix_map -- dictionary mapping suffixes to suffixes
    encodings_map -- dictionary mapping suffixes to encodings
    types_map -- dictionary mapping suffixes to types

    Functions:

    init([files]) -- parse a list of files, default knownfiles (on Windows, the
     default values are taken from the registry)
    read_mime_types(file) -- parse one file, return a dictionary or None
    """
    from itertools import count

    import os
    import sys
    import posixpath
    import urllib
    try:
     import _winreg
    except ImportError:
     _winreg = None

    __all__ = [
     "guess_type","guess_extension","guess_all_extensions",
     "add_type","read_mime_types","init"
    ]

    knownfiles = [
     "/etc/mime.types",
     "/etc/httpd/mime.types",     # Mac OS X
     "/etc/httpd/conf/mime.types",    # Apache
     "/etc/apache/mime.types",     # Apache 1
     "/etc/apache2/mime.types",     # Apache 2
     "/usr/local/etc/httpd/conf/mime.types",
     "/usr/local/lib/netscape/mime.types",
     "/usr/local/etc/httpd/conf/mime.types",  # Apache 1.2
     "/usr/local/etc/mime.types",    # Apache 1.3
     ]

    inited = False
    _db = None


    class MimeTypes:
     """MIME-types datastore.

     This datastore can handle information from mime.types-style files
     and supports basic determination of MIME type from a filename or
     URL, and can guess a reasonable extension given a MIME type.
     """

     def __init__(self, filenames=(), strict=True):
      if not inited:
       init()
      self.encodings_map = encodings_map.copy()
      self.suffix_map = suffix_map.copy()
      self.types_map = ({}, {}) # dict for (non-strict, strict)
      self.types_map_inv = ({}, {})
      for (ext, type) in types_map.items():
       self.add_type(type, ext, True)
      for (ext, type) in common_types.items():
       self.add_type(type, ext, False)
      for name in filenames:
       self.read(name, strict)

     def add_type(self, type, ext, strict=True):
      """Add a mapping between a type and an extension.

      When the extension is already known, the new
      type will replace the old one. When the type
      is already known the extension will be added
      to the list of known extensions.

      If strict is true, information will be added to
      list of standard types, else to the list of non-standard
      types.
      """
      self.types_map[strict][ext] = type
      exts = self.types_map_inv[strict].setdefault(type, [])
      if ext not in exts:
       exts.append(ext)

     def guess_type(self, url, strict=True):
      """Guess the type of a file based on its URL.

      Return value is a tuple (type, encoding) where type is None if
      the type can't be guessed (no or unknown suffix) or a string
      of the form type/subtype, usable for a MIME Content-type
      header; and encoding is None for no encoding or the name of
      the program used to encode (e.g. compress or gzip). The
      mappings are table driven. Encoding suffixes are case
      sensitive; type suffixes are first tried case sensitive, then
      case insensitive.

      The suffixes .tgz, .taz and .tz (case sensitive!) are all
      mapped to '.tar.gz'. (This is table-driven too, using the
      dictionary suffix_map.)

      Optional `strict' argument when False adds a bunch of commonly found,
      but non-standard types.
      """
      scheme, url = urllib.splittype(url)
      if scheme == 'data':
       # syntax of data URLs:
       # dataurl := "data:" [ mediatype ] [ ";base64" ] "," data
       # mediatype := [ type "/" subtype ] *( ";" parameter )
       # data  := *urlchar
       # parameter := attribute "=" value
       # type/subtype defaults to "text/plain"
       comma = url.find(',')
       if comma < 0:
        # bad data URL
        return None, None
       semi = url.find(';', 0, comma)
       if semi >= 0:
        type = url[:semi]
       else:
        type = url[:comma]
       if '=' in type or '/' not in type:
        type = 'text/plain'
       return type, None   # never compressed, so encoding is None
      base, ext = posixpath.splitext(url)
      while ext in self.suffix_map:
       base, ext = posixpath.splitext(base + self.suffix_map[ext])
      if ext in self.encodings_map:
       encoding = self.encodings_map[ext]
       base, ext = posixpath.splitext(base)
      else:
       encoding = None
      types_map = self.types_map[True]
      if ext in types_map:
       return types_map[ext], encoding
      elif ext.lower() in types_map:
       return types_map[ext.lower()], encoding
      elif strict:
       return None, encoding
      types_map = self.types_map[False]
      if ext in types_map:
       return types_map[ext], encoding
      elif ext.lower() in types_map:
       return types_map[ext.lower()], encoding
      else:
       return None, encoding

     def guess_all_extensions(self, type, strict=True):
      """Guess the extensions for a file based on its MIME type.

      Return value is a list of strings giving the possible filename
      extensions, including the leading dot ('.'). The extension is not
      guaranteed to have been associated with any particular data stream,
      but would be mapped to the MIME type `type' by guess_type().

      Optional `strict' argument when false adds a bunch of commonly found,
      but non-standard types.
      """
      type = type.lower()
      extensions = self.types_map_inv[True].get(type, [])
      if not strict:
       for ext in self.types_map_inv[False].get(type, []):
        if ext not in extensions:
         extensions.append(ext)
      return extensions

     def guess_extension(self, type, strict=True):
      """Guess the extension for a file based on its MIME type.

      Return value is a string giving a filename extension,
      including the leading dot ('.'). The extension is not
      guaranteed to have been associated with any particular data
      stream, but would be mapped to the MIME type `type' by
      guess_type(). If no extension can be guessed for `type', None
      is returned.

      Optional `strict' argument when false adds a bunch of commonly found,
      but non-standard types.
      """
      extensions = self.guess_all_extensions(type, strict)
      if not extensions:
       return None
      return extensions[0]

     def read(self, filename, strict=True):
      """
      Read a single mime.types-format file, specified by pathname.

      If strict is true, information will be added to
      list of standard types, else to the list of non-standard
      types.
      """
      with open(filename) as fp:
       self.readfp(fp, strict)

     def readfp(self, fp, strict=True):
      """
      Read a single mime.types-format file.

      If strict is true, information will be added to
      list of standard types, else to the list of non-standard
      types.
      """
      while 1:
       line = fp.readline()
       if not line:
        break
       words = line.split()
       for i in range(len(words)):
        if words[i][0] == '#':
         del words[i:]
         break
       if not words:
        continue
       type, suffixes = words[0], words[1:]
       for suff in suffixes:
        self.add_type(type, '.' + suff, strict)

     def read_windows_registry(self, strict=True):
      """
      Load the MIME types database from Windows registry.

      If strict is true, information will be added to
      list of standard types, else to the list of non-standard
      types.
      """

      # Windows only
      if not _winreg:
       return

      def enum_types(mimedb):
       for i in count():
        try:
         yield _winreg.EnumKey(mimedb, i)
        except EnvironmentError:
         break

      default_encoding = sys.getdefaultencoding()
      with _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT, '') as hkcr:
       for subkeyname in enum_types(hkcr):
        try:
         with _winreg.OpenKey(hkcr, subkeyname) as subkey:
          # Only check file extensions
          if not subkeyname.startswith("."):
           continue
          # raises EnvironmentError if no 'Content Type' value
          mimetype, datatype = _winreg.QueryValueEx(
           subkey, 'Content Type')
          if datatype != _winreg.REG_SZ:
           continue
          try:
           mimetype = mimetype.encode(default_encoding)
           subkeyname = subkeyname.encode(default_encoding)
          except UnicodeEncodeError:
           continue
          self.add_type(mimetype, subkeyname, strict)
        except EnvironmentError:
         continue

    def guess_type(url, strict=True):
     """Guess the type of a file based on its URL.

     Return value is a tuple (type, encoding) where type is None if the
     type can't be guessed (no or unknown suffix) or a string of the
     form type/subtype, usable for a MIME Content-type header; and
     encoding is None for no encoding or the name of the program used
     to encode (e.g. compress or gzip). The mappings are table
     driven. Encoding suffixes are case sensitive; type suffixes are
     first tried case sensitive, then case insensitive.

     The suffixes .tgz, .taz and .tz (case sensitive!) are all mapped
     to ".tar.gz". (This is table-driven too, using the dictionary
     suffix_map).

     Optional `strict' argument when false adds a bunch of commonly found, but
     non-standard types.
     """
     if _db is None:
      init()
     return _db.guess_type(url, strict)


    def guess_all_extensions(type, strict=True):
     """Guess the extensions for a file based on its MIME type.

     Return value is a list of strings giving the possible filename
     extensions, including the leading dot ('.'). The extension is not
     guaranteed to have been associated with any particular data
     stream, but would be mapped to the MIME type `type' by
     guess_type(). If no extension can be guessed for `type', None
     is returned.

     Optional `strict' argument when false adds a bunch of commonly found,
     but non-standard types.
     """
     if _db is None:
      init()
     return _db.guess_all_extensions(type, strict)

    def guess_extension(type, strict=True):
     """Guess the extension for a file based on its MIME type.

     Return value is a string giving a filename extension, including the
     leading dot ('.'). The extension is not guaranteed to have been
     associated with any particular data stream, but would be mapped to the
     MIME type `type' by guess_type(). If no extension can be guessed for
     `type', None is returned.

     Optional `strict' argument when false adds a bunch of commonly found,
     but non-standard types.
     """
     if _db is None:
      init()
     return _db.guess_extension(type, strict)

    def add_type(type, ext, strict=True):
     """Add a mapping between a type and an extension.

     When the extension is already known, the new
     type will replace the old one. When the type
     is already known the extension will be added
     to the list of known extensions.

     If strict is true, information will be added to
     list of standard types, else to the list of non-standard
     types.
     """
     if _db is None:
      init()
     return _db.add_type(type, ext, strict)


    def init(files=None):
     global suffix_map, types_map, encodings_map, common_types
     global inited, _db
     inited = True # so that MimeTypes.__init__() doesn't call us again
     db = MimeTypes()
     if files is None:
      if _winreg:
       db.read_windows_registry()
      files = knownfiles
     for file in files:
      if os.path.isfile(file):
       db.read(file)
     encodings_map = db.encodings_map
     suffix_map = db.suffix_map
     types_map = db.types_map[True]
     common_types = db.types_map[False]
     # Make the DB a global variable now that it is fully initialized
     _db = db


    def read_mime_types(file):
     try:
      f = open(file)
     except IOError:
      return None
     db = MimeTypes()
     db.readfp(f, True)
     return db.types_map[True]


    def _default_mime_types():
     global suffix_map
     global encodings_map
     global types_map
     global common_types

     suffix_map = {
      '.tgz': '.tar.gz',
      '.taz': '.tar.gz',
      '.tz': '.tar.gz',
      '.tbz2': '.tar.bz2',
      '.txz': '.tar.xz',
      }

     encodings_map = {
      '.gz': 'gzip',
      '.Z': 'compress',
      '.bz2': 'bzip2',
      '.xz': 'xz',
      }

     # Before adding new types, make sure they are either registered with IANA,
     # at http://www.isi.edu/in-notes/iana/assignments/media-types
     # or extensions, i.e. using the x- prefix

     # If you add to these, please keep them sorted!
     types_map = {
      '.a'  : 'application/octet-stream',
      '.ai'  : 'application/postscript',
      '.aif' : 'audio/x-aiff',
      '.aifc' : 'audio/x-aiff',
      '.aiff' : 'audio/x-aiff',
      '.au'  : 'audio/basic',
      '.avi' : 'video/x-msvideo',
      '.bat' : 'text/plain',
      '.bcpio' : 'application/x-bcpio',
      '.bin' : 'application/octet-stream',
      '.bmp' : 'image/x-ms-bmp',
      '.c'  : 'text/plain',
      # Duplicates �
      '.cdf' : 'application/x-cdf',
      '.cdf' : 'application/x-netcdf',
      '.cpio' : 'application/x-cpio',
      '.csh' : 'application/x-csh',
      '.css' : 'text/css',
      '.dll' : 'application/octet-stream',
      '.doc' : 'application/msword',
      '.dot' : 'application/msword',
      '.dvi' : 'application/x-dvi',
      '.eml' : 'message/rfc822',
      '.eps' : 'application/postscript',
      '.etx' : 'text/x-setext',
      '.exe' : 'application/octet-stream',
      '.gif' : 'image/gif',
      '.gtar' : 'application/x-gtar',
      '.h'  : 'text/plain',
      '.hdf' : 'application/x-hdf',
      '.htm' : 'text/html',
      '.html' : 'text/html',
      '.ico' : 'image/vnd.microsoft.icon',
      '.ief' : 'image/ief',
      '.jpe' : 'image/jpeg',
      '.jpeg' : 'image/jpeg',
      '.jpg' : 'image/jpeg',
      '.js'  : 'application/javascript',
      '.ksh' : 'text/plain',
      '.latex' : 'application/x-latex',
      '.m1v' : 'video/mpeg',
      '.man' : 'application/x-troff-man',
      '.me'  : 'application/x-troff-me',
      '.mht' : 'message/rfc822',
      '.mhtml' : 'message/rfc822',
      '.mif' : 'application/x-mif',
      '.mov' : 'video/quicktime',
      '.movie' : 'video/x-sgi-movie',
      '.mp2' : 'audio/mpeg',
      '.mp3' : 'audio/mpeg',
      '.mp4' : 'video/mp4',
      '.mpa' : 'video/mpeg',
      '.mpe' : 'video/mpeg',
      '.mpeg' : 'video/mpeg',
      '.mpg' : 'video/mpeg',
      '.ms'  : 'application/x-troff-ms',
      '.nc'  : 'application/x-netcdf',
      '.nws' : 'message/rfc822',
      '.o'  : 'application/octet-stream',
      '.obj' : 'application/octet-stream',
      '.oda' : 'application/oda',
      '.p12' : 'application/x-pkcs12',
      '.p7c' : 'application/pkcs7-mime',
      '.pbm' : 'image/x-portable-bitmap',
      '.pdf' : 'application/pdf',
      '.pfx' : 'application/x-pkcs12',
      '.pgm' : 'image/x-portable-graymap',
      '.pl'  : 'text/plain',
      '.png' : 'image/png',
      '.pnm' : 'image/x-portable-anymap',
      '.pot' : 'application/vnd.ms-powerpoint',
      '.ppa' : 'application/vnd.ms-powerpoint',
      '.ppm' : 'image/x-portable-pixmap',
      '.pps' : 'application/vnd.ms-powerpoint',
      '.ppt' : 'application/vnd.ms-powerpoint',
      '.ps'  : 'application/postscript',
      '.pwz' : 'application/vnd.ms-powerpoint',
      '.py'  : 'text/x-python',
      '.pyc' : 'application/x-python-code',
      '.pyo' : 'application/x-python-code',
      '.qt'  : 'video/quicktime',
      '.ra'  : 'audio/x-pn-realaudio',
      '.ram' : 'application/x-pn-realaudio',
      '.ras' : 'image/x-cmu-raster',
      '.rdf' : 'application/xml',
      '.rgb' : 'image/x-rgb',
      '.roff' : 'application/x-troff',
      '.rtx' : 'text/richtext',
      '.sgm' : 'text/x-sgml',
      '.sgml' : 'text/x-sgml',
      '.sh'  : 'application/x-sh',
      '.shar' : 'application/x-shar',
      '.snd' : 'audio/basic',
      '.so'  : 'application/octet-stream',
      '.src' : 'application/x-wais-source',
      '.sv4cpio': 'application/x-sv4cpio',
      '.sv4crc' : 'application/x-sv4crc',
      '.swf' : 'application/x-shockwave-flash',
      '.t'  : 'application/x-troff',
      '.tar' : 'application/x-tar',
      '.tcl' : 'application/x-tcl',
      '.tex' : 'application/x-tex',
      '.texi' : 'application/x-texinfo',
      '.texinfo': 'application/x-texinfo',
      '.tif' : 'image/tiff',
      '.tiff' : 'image/tiff',
      '.tr'  : 'application/x-troff',
      '.tsv' : 'text/tab-separated-values',
      '.txt' : 'text/plain',
      '.ustar' : 'application/x-ustar',
      '.vcf' : 'text/x-vcard',
      '.wav' : 'audio/x-wav',
      '.wiz' : 'application/msword',
      '.wsdl' : 'application/xml',
      '.xbm' : 'image/x-xbitmap',
      '.xlb' : 'application/vnd.ms-excel',
      # Duplicates �
      '.xls' : 'application/excel',
      '.xls' : 'application/vnd.ms-excel',
      '.xml' : 'text/xml',
      '.xpdl' : 'application/xml',
      '.xpm' : 'image/x-xpixmap',
      '.xsl' : 'application/xml',
      '.xwd' : 'image/x-xwindowdump',
      '.zip' : 'application/zip',
      }

     # These are non-standard types, commonly found in the wild. They will
     # only match if strict=0 flag is given to the API methods.

     # Please sort these too
     common_types = {
      '.jpg' : 'image/jpg',
      '.mid' : 'audio/midi',
      '.midi': 'audio/midi',
      '.pct' : 'image/pict',
      '.pic' : 'image/pict',
      '.pict': 'image/pict',
      '.rtf' : 'application/rtf',
      '.xul' : 'text/xul'
      }


    _default_mime_types()


    if __name__ == '__main__':
     import getopt

     USAGE = """\
    Usage: mimetypes.py [options] type

    Options:
     --help / -h  -- print this message and exit
     --lenient / -l -- additionally search of some common, but non-standard
           types.
     --extension / -e -- guess extension instead of type

    More than one type argument may be given.
    """

     def usage(code, msg=''):
      print USAGE
      if msg: print msg
      sys.exit(code)

     try:
      opts, args = getopt.getopt(sys.argv[1:], 'hle',
             ['help', 'lenient', 'extension'])
     except getopt.error, msg:
      usage(1, msg)

     strict = 1
     extension = 0
     for opt, arg in opts:
      if opt in ('-h', '--help'):
       usage(0)
      elif opt in ('-l', '--lenient'):
       strict = 0
      elif opt in ('-e', '--extension'):
       extension = 1
     for gtype in args:
      if extension:
       guess = guess_extension(gtype, strict)
       if not guess: print "I don't know anything about type", gtype
       else: print guess
      else:
       guess, encoding = guess_type(gtype, strict)
       if not guess: print "I don't know anything about type", gtype
       else: print 'type:', guess, 'encoding:', encoding

附上一篇关于python编码的帖子

1. pyhton的所有内置库、方法接受的是unicode编码的字符串。

2. str.decode 函数就是转成unicode编码，所以能decode的字符串传进python的内置库、函数都能正确运行。

3.问题在于这个decode函数解码时到底要传哪个参数：utf-8,gbk,gb2312......等N种编码。参数不当，就会抛类似异常：

复制代码 代码如下:

UnicodeDecodeError: 'gbk' codec can't decode bytes in position 2-3: illegal multibyte sequence

UnicodeDecodeError: 'utf8' codec can't decode bytes in position 0-1: invalid data