python 2.7 の getpass.py

20:30追記せっかちな人は続 PYTHON 2.7 の GETPASS.PYをお読み下さい。そうでないなら、順にどーぞ。


 

Python 2.7 のgetpass — 可搬性のあるパスワード入力機構は下らないところでマズくて。プロンプトに Unicode 使えない。特に Windows でマズくて、プロンプトのみならず Unicode 使えない。

Python3.xでは FIX されているので、そのまま持って来れないかなぁ、と思った。

Mercurial > cpython view Lib/getpass.py @ 87173:c3896275c0f6(3.3.3のもの)より持ってくる(「raw」からダウンロードすればいい)。名前は好きにすれば良いと思うが、Python 2.7 のために必要な改造は2行追加のみ:

py333_getpass.pyの先頭に
1 from __future__ import unicode_literals
2 from __future__ import print_function

一応「3.3.3」に対しての、全部載っけとく:

py333_getpass.py
  1 """Utilities to get a password and/or the current user name.
  2 
  3 getpass(prompt[, stream]) - Prompt for a password, with echo turned off.
  4 getuser() - Get the user name from the environment or password database.
  5 
  6 GetPassWarning - This UserWarning is issued when getpass() cannot prevent
  7                  echoing of the password contents while reading.
  8 
  9 On Windows, the msvcrt module will be used.
 10 On the Mac EasyDialogs.AskPassword is used, if available.
 11 
 12 """
 13 from __future__ import unicode_literals
 14 from __future__ import print_function
 15 
 16 # Authors: Piers Lauder (original)
 17 #          Guido van Rossum (Windows support and cleanup)
 18 #          Gregory P. Smith (tty support & GetPassWarning)
 19 
 20 import os, sys, warnings
 21 
 22 __all__ = ["getpass","getuser","GetPassWarning"]
 23 
 24 
 25 class GetPassWarning(UserWarning): pass
 26 
 27 
 28 def unix_getpass(prompt='Password: ', stream=None):
 29     """Prompt for a password, with echo turned off.
 30 
 31     Args:
 32       prompt: Written on stream to ask for the input.  Default: 'Password: '
 33       stream: A writable file object to display the prompt.  Defaults to
 34               the tty.  If no tty is available defaults to sys.stderr.
 35     Returns:
 36       The seKr3t input.
 37     Raises:
 38       EOFError: If our input tty or stdin was closed.
 39       GetPassWarning: When we were unable to turn echo off on the input.
 40 
 41     Always restores terminal settings before returning.
 42     """
 43     fd = None
 44     tty = None
 45     try:
 46         # Always try reading and writing directly on the tty first.
 47         fd = os.open('/dev/tty', os.O_RDWR|os.O_NOCTTY)
 48         tty = os.fdopen(fd, 'w+', 1)
 49         input = tty
 50         if not stream:
 51             stream = tty
 52     except EnvironmentError as e:
 53         # If that fails, see if stdin can be controlled.
 54         try:
 55             fd = sys.stdin.fileno()
 56         except (AttributeError, ValueError):
 57             passwd = fallback_getpass(prompt, stream)
 58         input = sys.stdin
 59         if not stream:
 60             stream = sys.stderr
 61 
 62     if fd is not None:
 63         passwd = None
 64         try:
 65             old = termios.tcgetattr(fd)     # a copy to save
 66             new = old[:]
 67             new[3] &= ~termios.ECHO  # 3 == 'lflags'
 68             tcsetattr_flags = termios.TCSAFLUSH
 69             if hasattr(termios, 'TCSASOFT'):
 70                 tcsetattr_flags |= termios.TCSASOFT
 71             try:
 72                 termios.tcsetattr(fd, tcsetattr_flags, new)
 73                 passwd = _raw_input(prompt, stream, input=input)
 74             finally:
 75                 termios.tcsetattr(fd, tcsetattr_flags, old)
 76                 stream.flush()  # issue7208
 77         except termios.error:
 78             if passwd is not None:
 79                 # _raw_input succeeded.  The final tcsetattr failed.  Reraise
 80                 # instead of leaving the terminal in an unknown state.
 81                 raise
 82             # We can't control the tty or stdin.  Give up and use normal IO.
 83             # fallback_getpass() raises an appropriate warning.
 84             del input, tty  # clean up unused file objects before blocking
 85             passwd = fallback_getpass(prompt, stream)
 86 
 87     stream.write('\n')
 88     return passwd
 89 
 90 
 91 def win_getpass(prompt='Password: ', stream=None):
 92     """Prompt for password with echo off, using Windows getch()."""
 93     if sys.stdin is not sys.__stdin__:
 94         return fallback_getpass(prompt, stream)
 95     import msvcrt
 96     for c in prompt:
 97         msvcrt.putwch(c)
 98     pw = ""
 99     while 1:
100         c = msvcrt.getwch()
101         if c == '\r' or c == '\n':
102             break
103         if c == '\003':
104             raise KeyboardInterrupt
105         if c == '\b':
106             pw = pw[:-1]
107         else:
108             pw = pw + c
109     msvcrt.putwch('\r')
110     msvcrt.putwch('\n')
111     return pw
112 
113 
114 def fallback_getpass(prompt='Password: ', stream=None):
115     warnings.warn("Can not control echo on the terminal.", GetPassWarning,
116                   stacklevel=2)
117     if not stream:
118         stream = sys.stderr
119     print("Warning: Password input may be echoed.", file=stream)
120     return _raw_input(prompt, stream)
121 
122 
123 def _raw_input(prompt="", stream=None, input=None):
124     # This doesn't save the string in the GNU readline history.
125     if not stream:
126         stream = sys.stderr
127     if not input:
128         input = sys.stdin
129     prompt = str(prompt)
130     if prompt:
131         stream.write(prompt)
132         stream.flush()
133     # NOTE: The Python C API calls flockfile() (and unlock) during readline.
134     line = input.readline()
135     if not line:
136         raise EOFError
137     if line[-1] == '\n':
138         line = line[:-1]
139     return line
140 
141 
142 def getuser():
143     """Get the username from the environment or password database.
144 
145     First try various environment variables, then the password
146     database.  This works on Windows as long as USERNAME is set.
147 
148     """
149 
150     for name in ('LOGNAME', 'USER', 'LNAME', 'USERNAME'):
151         user = os.environ.get(name)
152         if user:
153             return user
154 
155     # If this fails, the exception will "explain" why
156     import pwd
157     return pwd.getpwuid(os.getuid())[0]
158 
159 # Bind the name getpass to the appropriate function
160 try:
161     import termios
162     # it's possible there is an incompatible termios from the
163     # McMillan Installer, make sure we have a UNIX-compatible termios
164     termios.tcgetattr, termios.tcsetattr
165 except (ImportError, AttributeError):
166     try:
167         import msvcrt
168     except ImportError:
169         getpass = fallback_getpass
170     else:
171         getpass = win_getpass
172 else:
173     getpass = unix_getpass

unix_getpass は 3.3.4 以降のものが、contextlib のインターフェイスの違いで、動かない。なお、3.3.3 のものは、Mac での「from EasyDialogs import AskPassword」をかわりにつかうのをやめているみたい。ワタシ、生涯とおして一度として Mac ユーザであったことはないので良くわからないけど。

getpass

msvcrt.getch()、msvcrt.putch() ではなく msvcrt.getwch()、msvcrt.putwch() に変更されたのは 2007 年なのだが、Python 2.7 では取り込まれてない。msvcrt 関数は C 拡張なので 2.7 時点で既にバイトなのか unicode なのかは区別していて、msvcrt.getwch()、msvcrt.putwch() に置換するだけでは 2.7 ではエラーになる。これはこういうこと:

1 Python 2.7.9 (default, Dec 10 2014, 12:28:03) [MSC v.1500 64 bit (AMD64)] on win32
2 Type "help", "copyright", "credits" or "license" for more information.
3 >>> type("aaa")
4 <type 'str'>
5 >>> type(u"aaa")
6 <type 'unicode'>
7 >>>

ので getwchar()、putwchar() は「str」(Python 3.x での bytes そのもの)を拒絶する。

py3_getpass.pyの先頭に
1 from __future__ import unicode_literals

はこのためのもの。

なお、

py3_getpass.pyの先頭に
1 from __future__ import print_function

は、「Python 2.x から Python 3.x で大き過ぎる破壊された互換性」のいくつかのうち、一番有名で一番しょーもなくて、一番対処しやすいやつ。あたしゃ print に括弧つける癖がついちまったよ。