view MoinMoin/support/passlib/apache.py @ 6111:1fdd537e9d83

SubProcess: reimplement exec_cmd subclassing Popen and overriding some methods isn't pretty. the code we have was written for py 2.4 or so and the py 2.7 Popen looked quite different. this way with the timer should be less problematic.
author Thomas Waldmann <tw AT waldmann-edv DOT de>
date Tue, 06 Sep 2016 04:39:28 +0200
parents 86a41c2bedec
children 7f0616feeae9
line wrap: on
line source
"""passlib.apache - apache password support"""
# XXX: relocate this to passlib.ext.apache?
#=============================================================================
# imports
#=============================================================================
from __future__ import with_statement
# core
from hashlib import md5
import logging; log = logging.getLogger(__name__)
import os
import sys
from warnings import warn
# site
# pkg
from passlib.context import CryptContext
from passlib.exc import ExpectedStringError
from passlib.hash import htdigest
from passlib.utils import consteq, render_bytes, to_bytes, deprecated_method, is_ascii_codec
from passlib.utils.compat import b, bytes, join_bytes, str_to_bascii, u, \
                                 unicode, BytesIO, iteritems, imap, PY3
# local
__all__ = [
    'HtpasswdFile',
    'HtdigestFile',
]

#=============================================================================
# constants & support
#=============================================================================
_UNSET = object()

_BCOLON = b(":")

# byte values that aren't allowed in fields.
_INVALID_FIELD_CHARS = b(":\n\r\t\x00")

#=============================================================================
# backport of OrderedDict for PY2.5
#=============================================================================
try:
    from collections import OrderedDict
except ImportError:
    # Python 2.5
    class OrderedDict(dict):
        """hacked OrderedDict replacement.

        NOTE: this doesn't provide a full OrderedDict implementation,
        just the minimum needed by the Htpasswd internals.
        """
        def __init__(self):
            self._keys = []

        def __iter__(self):
            return iter(self._keys)

        def __setitem__(self, key, value):
            if key not in self:
                self._keys.append(key)
            super(OrderedDict, self).__setitem__(key, value)

        def __delitem__(self, key):
            super(OrderedDict, self).__delitem__(key)
            self._keys.remove(key)

        def iteritems(self):
            return ((key, self[key]) for key in self)

        # these aren't used or implemented, so disabling them for safety.
        update = pop = popitem = clear = keys = iterkeys = None

#=============================================================================
# common helpers
#=============================================================================
class _CommonFile(object):
    """common framework for HtpasswdFile & HtdigestFile"""
    #===================================================================
    # instance attrs
    #===================================================================

    # charset encoding used by file (defaults to utf-8)
    encoding = None

    # whether users() and other public methods should return unicode or bytes?
    # (defaults to False under PY2, True under PY3)
    return_unicode = None

    # if bound to local file, these will be set.
    _path = None # local file path
    _mtime = None # mtime when last loaded, or 0

    # if true, automatically save to local file after changes are made.
    autosave = False

    # ordered dict mapping key -> value for all records in database.
    # (e.g. user => hash for Htpasswd)
    _records = None

    #===================================================================
    # alt constuctors
    #===================================================================
    @classmethod
    def from_string(cls, data, **kwds):
        """create new object from raw string.

        :type data: unicode or bytes
        :arg data:
            database to load, as single string.

        :param \*\*kwds:
            all other keywords are the same as in the class constructor
        """
        if 'path' in kwds:
            raise TypeError("'path' not accepted by from_string()")
        self = cls(**kwds)
        self.load_string(data)
        return self

    @classmethod
    def from_path(cls, path, **kwds):
        """create new object from file, without binding object to file.

        :type path: str
        :arg path:
            local filepath to load from

        :param \*\*kwds:
            all other keywords are the same as in the class constructor
        """
        self = cls(**kwds)
        self.load(path)
        return self

    #===================================================================
    # init
    #===================================================================
    def __init__(self, path=None, new=False, autoload=True, autosave=False,
                 encoding="utf-8", return_unicode=PY3,
                 ):
        # set encoding
        if not encoding:
            warn("``encoding=None`` is deprecated as of Passlib 1.6, "
                 "and will cause a ValueError in Passlib 1.8, "
                 "use ``return_unicode=False`` instead.",
                 DeprecationWarning, stacklevel=2)
            encoding = "utf-8"
            return_unicode = False
        elif not is_ascii_codec(encoding):
            # htpasswd/htdigest files assumes 1-byte chars, and use ":" separator,
            # so only ascii-compatible encodings are allowed.
            raise ValueError("encoding must be 7-bit ascii compatible")
        self.encoding = encoding

        # set other attrs
        self.return_unicode = return_unicode
        self.autosave = autosave
        self._path = path
        self._mtime = 0

        # init db
        if not autoload:
            warn("``autoload=False`` is deprecated as of Passlib 1.6, "
                 "and will be removed in Passlib 1.8, use ``new=True`` instead",
                 DeprecationWarning, stacklevel=2)
            new = True
        if path and not new:
            self.load()
        else:
            self._records = OrderedDict()

    def __repr__(self):
        tail = ''
        if self.autosave:
            tail += ' autosave=True'
        if self._path:
            tail += ' path=%r' % self._path
        if self.encoding != "utf-8":
            tail += ' encoding=%r' % self.encoding
        return "<%s 0x%0x%s>" % (self.__class__.__name__, id(self), tail)

    # NOTE: ``path`` is a property so that ``_mtime`` is wiped when it's set.
    def _get_path(self):
        return self._path
    def _set_path(self, value):
        if value != self._path:
            self._mtime = 0
        self._path = value
    path = property(_get_path, _set_path)

    @property
    def mtime(self):
        """modify time when last loaded (if bound to a local file)"""
        return self._mtime

    #===================================================================
    # loading
    #===================================================================
    def load_if_changed(self):
        """Reload from ``self.path`` only if file has changed since last load"""
        if not self._path:
            raise RuntimeError("%r is not bound to a local file" % self)
        if self._mtime and self._mtime == os.path.getmtime(self._path):
            return False
        self.load()
        return True

    def load(self, path=None, force=True):
        """Load state from local file.
        If no path is specified, attempts to load from ``self.path``.

        :type path: str
        :arg path: local file to load from

        :type force: bool
        :param force:
            if ``force=False``, only load from ``self.path`` if file
            has changed since last load.

            .. deprecated:: 1.6
                This keyword will be removed in Passlib 1.8;
                Applications should use :meth:`load_if_changed` instead.
        """
        if path is not None:
            with open(path, "rb") as fh:
                self._mtime = 0
                self._load_lines(fh)
        elif not force:
            warn("%(name)s.load(force=False) is deprecated as of Passlib 1.6,"
                 "and will be removed in Passlib 1.8; "
                 "use %(name)s.load_if_changed() instead." %
                 dict(name=self.__class__.__name__),
                 DeprecationWarning, stacklevel=2)
            return self.load_if_changed()
        elif self._path:
            with open(self._path, "rb") as fh:
                self._mtime = os.path.getmtime(self._path)
                self._load_lines(fh)
        else:
            raise RuntimeError("%s().path is not set, an explicit path is required" %
                               self.__class__.__name__)
        return True

    def load_string(self, data):
        """Load state from unicode or bytes string, replacing current state"""
        data = to_bytes(data, self.encoding, "data")
        self._mtime = 0
        self._load_lines(BytesIO(data))

    def _load_lines(self, lines):
        """load from sequence of lists"""
        # XXX: found reference that "#" comment lines may be supported by
        #      htpasswd, should verify this, and figure out how to handle them.
        #      if true, this would also affect what can be stored in user field.
        # XXX: if multiple entries for a key, should we use the first one
        #      or the last one? going w/ first entry for now.
        # XXX: how should this behave if parsing fails? currently
        #      it will contain everything that was loaded up to error.
        #      could clear / restore old state instead.
        parse = self._parse_record
        records = self._records = OrderedDict()
        for idx, line in enumerate(lines):
            key, value = parse(line, idx+1)
            if key not in records:
                records[key] = value

    def _parse_record(self, record, lineno): # pragma: no cover - abstract method
        """parse line of file into (key, value) pair"""
        raise NotImplementedError("should be implemented in subclass")

    #===================================================================
    # saving
    #===================================================================
    def _autosave(self):
        """subclass helper to call save() after any changes"""
        if self.autosave and self._path:
            self.save()

    def save(self, path=None):
        """Save current state to file.
        If no path is specified, attempts to save to ``self.path``.
        """
        if path is not None:
            with open(path, "wb") as fh:
                fh.writelines(self._iter_lines())
        elif self._path:
            self.save(self._path)
            self._mtime = os.path.getmtime(self._path)
        else:
            raise RuntimeError("%s().path is not set, cannot autosave" %
                               self.__class__.__name__)

    def to_string(self):
        """Export current state as a string of bytes"""
        return join_bytes(self._iter_lines())

    def _iter_lines(self):
        """iterator yielding lines of database"""
        return (self._render_record(key,value) for key,value in iteritems(self._records))

    def _render_record(self, key, value): # pragma: no cover - abstract method
        """given key/value pair, encode as line of file"""
        raise NotImplementedError("should be implemented in subclass")

    #===================================================================
    # field encoding
    #===================================================================
    def _encode_user(self, user):
        """user-specific wrapper for _encode_field()"""
        return self._encode_field(user, "user")

    def _encode_realm(self, realm): # pragma: no cover - abstract method
        """realm-specific wrapper for _encode_field()"""
        return self._encode_field(realm, "realm")

    def _encode_field(self, value, param="field"):
        """convert field to internal representation.

        internal representation is always bytes. byte strings are left as-is,
        unicode strings encoding using file's default encoding (or ``utf-8``
        if no encoding has been specified).

        :raises UnicodeEncodeError:
            if unicode value cannot be encoded using default encoding.

        :raises ValueError:
            if resulting byte string contains a forbidden character,
            or is too long (>255 bytes).

        :returns:
            encoded identifer as bytes
        """
        if isinstance(value, unicode):
            value = value.encode(self.encoding)
        elif not isinstance(value, bytes):
            raise ExpectedStringError(value, param)
        if len(value) > 255:
            raise ValueError("%s must be at most 255 characters: %r" %
                             (param, value))
        if any(c in _INVALID_FIELD_CHARS for c in value):
            raise ValueError("%s contains invalid characters: %r" %
                             (param, value,))
        return value

    def _decode_field(self, value):
        """decode field from internal representation to format
        returns by users() method, etc.

        :raises UnicodeDecodeError:
            if unicode value cannot be decoded using default encoding.
            (usually indicates wrong encoding set for file).

        :returns:
            field as unicode or bytes, as appropriate.
        """
        assert isinstance(value, bytes), "expected value to be bytes"
        if self.return_unicode:
            return value.decode(self.encoding)
        else:
            return value

    # FIXME: htpasswd doc says passwords limited to 255 chars under Windows & MPE,
    # and that longer ones are truncated. this may be side-effect of those
    # platforms supporting the 'plaintext' scheme. these classes don't currently
    # check for this.

    #===================================================================
    # eoc
    #===================================================================

#=============================================================================
# htpasswd editing
#=============================================================================

#: default CryptContext used by HtpasswdFile
# TODO: update this to support everything in host_context (where available),
#       and note in the documentation that the default is no longer guaranteed to be portable
#       across platforms.
#       c.f. http://httpd.apache.org/docs/2.2/programs/htpasswd.html
htpasswd_context = CryptContext([
    # man page notes supported everywhere; is default on Windows, Netware, TPF
    "apr_md5_crypt",

    # [added in passlib 1.6.3]
    # apache requires host crypt() support; but can generate natively
    # (as of https://bz.apache.org/bugzilla/show_bug.cgi?id=49288)
    "bcrypt",

    # [added in passlib 1.6.3]
    # apache requires host crypt() support; and can't generate natively
    "sha256_crypt",
    "sha512_crypt",

    # man page notes apache does NOT support this on Windows, Netware, TPF
    "des_crypt",

    # man page notes intended only for transitioning htpasswd <-> ldap
    "ldap_sha1",

    # man page notes apache ONLY supports this on Windows, Netware, TPF
    "plaintext"
    ])

#: scheme that will be used when 'portable' is requested.
portable_scheme = "apr_md5_crypt"


class HtpasswdFile(_CommonFile):
    """class for reading & writing Htpasswd files.

    The class constructor accepts the following arguments:

    :type path: filepath
    :param path:

        Specifies path to htpasswd file, use to implicitly load from and save to.

        This class has two modes of operation:

        1. It can be "bound" to a local file by passing a ``path`` to the class
           constructor. In this case it will load the contents of the file when
           created, and the :meth:`load` and :meth:`save` methods will automatically
           load from and save to that file if they are called without arguments.

        2. Alternately, it can exist as an independant object, in which case
           :meth:`load` and :meth:`save` will require an explicit path to be
           provided whenever they are called. As well, ``autosave`` behavior
           will not be available.

           This feature is new in Passlib 1.6, and is the default if no
           ``path`` value is provided to the constructor.

        This is also exposed as a readonly instance attribute.

    :type new: bool
    :param new:

        Normally, if *path* is specified, :class:`HtpasswdFile` will
        immediately load the contents of the file. However, when creating
        a new htpasswd file, applications can set ``new=True`` so that
        the existing file (if any) will not be loaded.

        .. versionadded:: 1.6
            This feature was previously enabled by setting ``autoload=False``.
            That alias has been deprecated, and will be removed in Passlib 1.8

    :type autosave: bool
    :param autosave:

        Normally, any changes made to an :class:`HtpasswdFile` instance
        will not be saved until :meth:`save` is explicitly called. However,
        if ``autosave=True`` is specified, any changes made will be
        saved to disk immediately (assuming *path* has been set).

        This is also exposed as a writeable instance attribute.

    :type encoding: str
    :param encoding:

        Optionally specify character encoding used to read/write file
        and hash passwords. Defaults to ``utf-8``, though ``latin-1``
        is the only other commonly encountered encoding.

        This is also exposed as a readonly instance attribute.

    :type default_scheme: str
    :param default_scheme:
        Optionally specify default scheme to use when encoding new passwords.
        May be any of ``"bcrypt"``, ``"sha256_crypt"``, ``"apr_md5_crypt"``, ``"des_crypt"``,
        ``"ldap_sha1"``, ``"plaintext"``. It defaults to ``"apr_md5_crypt"``.

        .. note::

            Some hashes are only supported by apache / htpasswd on certain operating systems
            (e.g. bcrypt on BSD, sha256_crypt on linux).  To get the strongest
            hash that's still portable, applications can specify ``default_scheme="portable"``.

        .. versionadded:: 1.6
            This keyword was previously named ``default``. That alias
            has been deprecated, and will be removed in Passlib 1.8.

        .. versionchanged:: 1.6.3

            Added support for ``"bcrypt"``, ``"sha256_crypt"``, and ``"portable"``.

    :type context: :class:`~passlib.context.CryptContext`
    :param context:
        :class:`!CryptContext` instance used to encrypt
        and verify the hashes found in the htpasswd file.
        The default value is a pre-built context which supports all
        of the hashes officially allowed in an htpasswd file.

        This is also exposed as a readonly instance attribute.

        .. warning::

            This option may be used to add support for non-standard hash
            formats to an htpasswd file. However, the resulting file
            will probably not be usable by another application,
            and particularly not by Apache.

    :param autoload:
        Set to ``False`` to prevent the constructor from automatically
        loaded the file from disk.

        .. deprecated:: 1.6
            This has been replaced by the *new* keyword.
            Instead of setting ``autoload=False``, you should use
            ``new=True``. Support for this keyword will be removed
            in Passlib 1.8.

    :param default:
        Change the default algorithm used to encrypt new passwords.

        .. deprecated:: 1.6
            This has been renamed to *default_scheme* for clarity.
            Support for this alias will be removed in Passlib 1.8.

    Loading & Saving
    ================
    .. automethod:: load
    .. automethod:: load_if_changed
    .. automethod:: load_string
    .. automethod:: save
    .. automethod:: to_string

    Inspection
    ================
    .. automethod:: users
    .. automethod:: check_password
    .. automethod:: get_hash

    Modification
    ================
    .. automethod:: set_password
    .. automethod:: delete

    Alternate Constructors
    ======================
    .. automethod:: from_string

    Attributes
    ==========
    .. attribute:: path

        Path to local file that will be used as the default
        for all :meth:`load` and :meth:`save` operations.
        May be written to, initialized by the *path* constructor keyword.

    .. attribute:: autosave

        Writeable flag indicating whether changes will be automatically
        written to *path*.

    Errors
    ======
    :raises ValueError:
        All of the methods in this class will raise a :exc:`ValueError` if
        any user name contains a forbidden character (one of ``:\\r\\n\\t\\x00``),
        or is longer than 255 characters.
    """
    #===================================================================
    # instance attrs
    #===================================================================

    # NOTE: _records map stores <user> for the key, and <hash> for the value,
    # both in bytes which use self.encoding

    #===================================================================
    # init & serialization
    #===================================================================
    def __init__(self, path=None, default_scheme=None, context=htpasswd_context,
                 **kwds):
        if 'default' in kwds:
            warn("``default`` is deprecated as of Passlib 1.6, "
                 "and will be removed in Passlib 1.8, it has been renamed "
                 "to ``default_scheem``.",
                 DeprecationWarning, stacklevel=2)
            default_scheme = kwds.pop("default")
        if default_scheme:
            if default_scheme == "portable":
                default_scheme = portable_scheme
            context = context.copy(default=default_scheme)
        self.context = context
        super(HtpasswdFile, self).__init__(path, **kwds)

    def _parse_record(self, record, lineno):
        # NOTE: should return (user, hash) tuple
        result = record.rstrip().split(_BCOLON)
        if len(result) != 2:
            raise ValueError("malformed htpasswd file (error reading line %d)"
                             % lineno)
        return result

    def _render_record(self, user, hash):
        return render_bytes("%s:%s\n", user, hash)

    #===================================================================
    # public methods
    #===================================================================

    def users(self):
        """Return list of all users in database"""
        return [self._decode_field(user) for user in self._records]

    ##def has_user(self, user):
    ##    "check whether entry is present for user"
    ##    return self._encode_user(user) in self._records

    ##def rename(self, old, new):
    ##    """rename user account"""
    ##    old = self._encode_user(old)
    ##    new = self._encode_user(new)
    ##    hash = self._records.pop(old)
    ##    self._records[new] = hash
    ##    self._autosave()

    def set_password(self, user, password):
        """Set password for user; adds user if needed.

        :returns:
            * ``True`` if existing user was updated.
            * ``False`` if user account was added.

        .. versionchanged:: 1.6
            This method was previously called ``update``, it was renamed
            to prevent ambiguity with the dictionary method.
            The old alias is deprecated, and will be removed in Passlib 1.8.
        """
        user = self._encode_user(user)
        hash = self.context.encrypt(password)
        if PY3:
            hash = hash.encode(self.encoding)
        existing = (user in self._records)
        self._records[user] = hash
        self._autosave()
        return existing

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="set_password")
    def update(self, user, password):
        """set password for user"""
        return self.set_password(user, password)

    def get_hash(self, user):
        """Return hash stored for user, or ``None`` if user not found.

        .. versionchanged:: 1.6
            This method was previously named ``find``, it was renamed
            for clarity. The old name is deprecated, and will be removed
            in Passlib 1.8.
        """
        try:
            return self._records[self._encode_user(user)]
        except KeyError:
            return None

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="get_hash")
    def find(self, user):
        """return hash for user"""
        return self.get_hash(user)

    # XXX: rename to something more explicit, like delete_user()?
    def delete(self, user):
        """Delete user's entry.

        :returns:
            * ``True`` if user deleted.
            * ``False`` if user not found.
        """
        try:
            del self._records[self._encode_user(user)]
        except KeyError:
            return False
        self._autosave()
        return True

    def check_password(self, user, password):
        """Verify password for specified user.

        :returns:
            * ``None`` if user not found.
            * ``False`` if user found, but password does not match.
            * ``True`` if user found and password matches.

        .. versionchanged:: 1.6
            This method was previously called ``verify``, it was renamed
            to prevent ambiguity with the :class:`!CryptContext` method.
            The old alias is deprecated, and will be removed in Passlib 1.8.
        """
        user = self._encode_user(user)
        hash = self._records.get(user)
        if hash is None:
            return None
        if isinstance(password, unicode):
            # NOTE: encoding password to match file, making the assumption
            # that server will use same encoding to hash the password.
            password = password.encode(self.encoding)
        ok, new_hash = self.context.verify_and_update(password, hash)
        if ok and new_hash is not None:
            # rehash user's password if old hash was deprecated
            self._records[user] = new_hash
            self._autosave()
        return ok

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="check_password")
    def verify(self, user, password):
        """verify password for user"""
        return self.check_password(user, password)

    #===================================================================
    # eoc
    #===================================================================

#=============================================================================
# htdigest editing
#=============================================================================
class HtdigestFile(_CommonFile):
    """class for reading & writing Htdigest files.

    The class constructor accepts the following arguments:

    :type path: filepath
    :param path:

        Specifies path to htdigest file, use to implicitly load from and save to.

        This class has two modes of operation:

        1. It can be "bound" to a local file by passing a ``path`` to the class
           constructor. In this case it will load the contents of the file when
           created, and the :meth:`load` and :meth:`save` methods will automatically
           load from and save to that file if they are called without arguments.

        2. Alternately, it can exist as an independant object, in which case
           :meth:`load` and :meth:`save` will require an explicit path to be
           provided whenever they are called. As well, ``autosave`` behavior
           will not be available.

           This feature is new in Passlib 1.6, and is the default if no
           ``path`` value is provided to the constructor.

        This is also exposed as a readonly instance attribute.

    :type default_realm: str
    :param default_realm:

        If ``default_realm`` is set, all the :class:`HtdigestFile`
        methods that require a realm will use this value if one is not
        provided explicitly. If unset, they will raise an error stating
        that an explicit realm is required.

        This is also exposed as a writeable instance attribute.

        .. versionadded:: 1.6

    :type new: bool
    :param new:

        Normally, if *path* is specified, :class:`HtdigestFile` will
        immediately load the contents of the file. However, when creating
        a new htpasswd file, applications can set ``new=True`` so that
        the existing file (if any) will not be loaded.

        .. versionadded:: 1.6
            This feature was previously enabled by setting ``autoload=False``.
            That alias has been deprecated, and will be removed in Passlib 1.8

    :type autosave: bool
    :param autosave:

        Normally, any changes made to an :class:`HtdigestFile` instance
        will not be saved until :meth:`save` is explicitly called. However,
        if ``autosave=True`` is specified, any changes made will be
        saved to disk immediately (assuming *path* has been set).

        This is also exposed as a writeable instance attribute.

    :type encoding: str
    :param encoding:

        Optionally specify character encoding used to read/write file
        and hash passwords. Defaults to ``utf-8``, though ``latin-1``
        is the only other commonly encountered encoding.

        This is also exposed as a readonly instance attribute.

    :param autoload:
        Set to ``False`` to prevent the constructor from automatically
        loaded the file from disk.

        .. deprecated:: 1.6
            This has been replaced by the *new* keyword.
            Instead of setting ``autoload=False``, you should use
            ``new=True``. Support for this keyword will be removed
            in Passlib 1.8.

    Loading & Saving
    ================
    .. automethod:: load
    .. automethod:: load_if_changed
    .. automethod:: load_string
    .. automethod:: save
    .. automethod:: to_string

    Inspection
    ==========
    .. automethod:: realms
    .. automethod:: users
    .. automethod:: check_password(user[, realm], password)
    .. automethod:: get_hash

    Modification
    ============
    .. automethod:: set_password(user[, realm], password)
    .. automethod:: delete
    .. automethod:: delete_realm

    Alternate Constructors
    ======================
    .. automethod:: from_string

    Attributes
    ==========
    .. attribute:: default_realm

        The default realm that will be used if one is not provided
        to methods that require it. By default this is ``None``,
        in which case an explicit realm must be provided for every
        method call. Can be written to.

    .. attribute:: path

        Path to local file that will be used as the default
        for all :meth:`load` and :meth:`save` operations.
        May be written to, initialized by the *path* constructor keyword.

    .. attribute:: autosave

        Writeable flag indicating whether changes will be automatically
        written to *path*.

    Errors
    ======
    :raises ValueError:
        All of the methods in this class will raise a :exc:`ValueError` if
        any user name or realm contains a forbidden character (one of ``:\\r\\n\\t\\x00``),
        or is longer than 255 characters.
    """
    #===================================================================
    # instance attrs
    #===================================================================

    # NOTE: _records map stores (<user>,<realm>) for the key,
    # and <hash> as the value, all as <self.encoding> bytes.

    # NOTE: unlike htpasswd, this class doesn't use a CryptContext,
    # as only one hash format is supported: htdigest.

    # optionally specify default realm that will be used if none
    # is provided to a method call. otherwise realm is always required.
    default_realm = None

    #===================================================================
    # init & serialization
    #===================================================================
    def __init__(self, path=None, default_realm=None, **kwds):
        self.default_realm = default_realm
        super(HtdigestFile, self).__init__(path, **kwds)

    def _parse_record(self, record, lineno):
        result = record.rstrip().split(_BCOLON)
        if len(result) != 3:
            raise ValueError("malformed htdigest file (error reading line %d)"
                             % lineno)
        user, realm, hash = result
        return (user, realm), hash

    def _render_record(self, key, hash):
        user, realm = key
        return render_bytes("%s:%s:%s\n", user, realm, hash)

    def _encode_realm(self, realm):
        # override default _encode_realm to fill in default realm field
        if realm is None:
            realm = self.default_realm
            if realm is None:
                raise TypeError("you must specify a realm explicitly, "
                                  "or set the default_realm attribute")
        return self._encode_field(realm, "realm")

    #===================================================================
    # public methods
    #===================================================================

    def realms(self):
        """Return list of all realms in database"""
        realms = set(key[1] for key in self._records)
        return [self._decode_field(realm) for realm in realms]

    def users(self, realm=None):
        """Return list of all users in specified realm.

        * uses ``self.default_realm`` if no realm explicitly provided.
        * returns empty list if realm not found.
        """
        realm = self._encode_realm(realm)
        return [self._decode_field(key[0]) for key in self._records
                if key[1] == realm]

    ##def has_user(self, user, realm=None):
    ##    "check if user+realm combination exists"
    ##    user = self._encode_user(user)
    ##    realm = self._encode_realm(realm)
    ##    return (user,realm) in self._records

    ##def rename_realm(self, old, new):
    ##    """rename all accounts in realm"""
    ##    old = self._encode_realm(old)
    ##    new = self._encode_realm(new)
    ##    keys = [key for key in self._records if key[1] == old]
    ##    for key in keys:
    ##        hash = self._records.pop(key)
    ##        self._records[key[0],new] = hash
    ##    self._autosave()
    ##    return len(keys)

    ##def rename(self, old, new, realm=None):
    ##    """rename user account"""
    ##    old = self._encode_user(old)
    ##    new = self._encode_user(new)
    ##    realm = self._encode_realm(realm)
    ##    hash = self._records.pop((old,realm))
    ##    self._records[new,realm] = hash
    ##    self._autosave()

    def set_password(self, user, realm=None, password=_UNSET):
        """Set password for user; adds user & realm if needed.

        If ``self.default_realm`` has been set, this may be called
        with the syntax ``set_password(user, password)``,
        otherwise it must be called with all three arguments:
        ``set_password(user, realm, password)``.

        :returns:
            * ``True`` if existing user was updated
            * ``False`` if user account added.
        """
        if password is _UNSET:
            # called w/ two args - (user, password), use default realm
            realm, password = None, realm
        user = self._encode_user(user)
        realm = self._encode_realm(realm)
        key = (user, realm)
        existing = (key in self._records)
        hash = htdigest.encrypt(password, user, realm, encoding=self.encoding)
        if PY3:
            hash = hash.encode(self.encoding)
        self._records[key] = hash
        self._autosave()
        return existing

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="set_password")
    def update(self, user, realm, password):
        """set password for user"""
        return self.set_password(user, realm, password)

    # XXX: rename to something more explicit, like get_hash()?
    def get_hash(self, user, realm=None):
        """Return :class:`~passlib.hash.htdigest` hash stored for user.

        * uses ``self.default_realm`` if no realm explicitly provided.
        * returns ``None`` if user or realm not found.

        .. versionchanged:: 1.6
            This method was previously named ``find``, it was renamed
            for clarity. The old name is deprecated, and will be removed
            in Passlib 1.8.
        """
        key = (self._encode_user(user), self._encode_realm(realm))
        hash = self._records.get(key)
        if hash is None:
            return None
        if PY3:
            hash = hash.decode(self.encoding)
        return hash

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="get_hash")
    def find(self, user, realm):
        """return hash for user"""
        return self.get_hash(user, realm)

    # XXX: rename to something more explicit, like delete_user()?
    def delete(self, user, realm=None):
        """Delete user's entry for specified realm.

        if realm is not specified, uses ``self.default_realm``.

        :returns:
            * ``True`` if user deleted,
            * ``False`` if user not found in realm.
        """
        key = (self._encode_user(user), self._encode_realm(realm))
        try:
            del self._records[key]
        except KeyError:
            return False
        self._autosave()
        return True

    def delete_realm(self, realm):
        """Delete all users for specified realm.

        if realm is not specified, uses ``self.default_realm``.

        :returns: number of users deleted (0 if realm not found)
        """
        realm = self._encode_realm(realm)
        records = self._records
        keys = [key for key in records if key[1] == realm]
        for key in keys:
            del records[key]
        self._autosave()
        return len(keys)

    def check_password(self, user, realm=None, password=_UNSET):
        """Verify password for specified user + realm.

        If ``self.default_realm`` has been set, this may be called
        with the syntax ``check_password(user, password)``,
        otherwise it must be called with all three arguments:
        ``check_password(user, realm, password)``.

        :returns:
            * ``None`` if user or realm not found.
            * ``False`` if user found, but password does not match.
            * ``True`` if user found and password matches.

        .. versionchanged:: 1.6
            This method was previously called ``verify``, it was renamed
            to prevent ambiguity with the :class:`!CryptContext` method.
            The old alias is deprecated, and will be removed in Passlib 1.8.
        """
        if password is _UNSET:
            # called w/ two args - (user, password), use default realm
            realm, password = None, realm
        user = self._encode_user(user)
        realm = self._encode_realm(realm)
        hash = self._records.get((user,realm))
        if hash is None:
            return None
        return htdigest.verify(password, hash, user, realm,
                               encoding=self.encoding)

    @deprecated_method(deprecated="1.6", removed="1.8",
                       replacement="check_password")
    def verify(self, user, realm, password):
        """verify password for user"""
        return self.check_password(user, realm, password)

    #===================================================================
    # eoc
    #===================================================================

#=============================================================================
# eof
#=============================================================================