view MoinMoin/user.py @ 1317:76a76def8687

remove most chmod calls, use 1 os.umask() call in request module instead (port from 1.5)
author Thomas Waldmann <tw AT waldmann-edv DOT de>
date Fri, 18 Aug 2006 21:20:15 +0200
parents 44632345fbfb
children 8a89649ab5f0
line wrap: on
line source
# -*- coding: iso-8859-1 -*-
"""
    MoinMoin - User Accounts

    @copyright: 2000-2004 by Jürgen Hermann <jh@web.de>
    @license: GNU GPL, see COPYING for details.
"""

# add names here to hide them in the cgitb traceback
unsafe_names = ("id", "key", "val", "user_data", "enc_password")

import os, time, sha, codecs

try:
    import cPickle as pickle
except ImportError:
    import pickle

# Set pickle protocol, see http://docs.python.org/lib/node64.html
PICKLE_PROTOCOL = pickle.HIGHEST_PROTOCOL

from MoinMoin import config, caching, wikiutil, i18n
from MoinMoin.util import filesys, timefuncs


def getUserList(request):
    """ Get a list of all (numerical) user IDs.

    @param request: current request
    @rtype: list
    @return: all user IDs
    """
    import re, dircache
    user_re = re.compile(r'^\d+\.\d+(\.\d+)?$')
    files = dircache.listdir(request.cfg.user_dir)
    userlist = [f for f in files if user_re.match(f)]
    return userlist

def get_by_email_address(request, email_address):
    """ Searches for a user with a particular e-mail address and
        returns it."""
    for uid in getUserList(request):
        theuser = User(request, uid)
        if theuser.valid and theuser.email.lower() == email_address.lower():
            return theuser

def getUserId(request, searchName):
    """
    Get the user ID for a specific user NAME.

    @param searchName: the user name to look up
    @rtype: string
    @return: the corresponding user ID or None
    """
    if not searchName:
        return None
    cfg = request.cfg
    try:
        _name2id = cfg._name2id
    except AttributeError:
        arena = 'user'
        key = 'name2id'
        cache = caching.CacheEntry(request, arena, key, scope='wiki')
        try:
            _name2id = pickle.loads(cache.content())
        except (pickle.UnpicklingError, IOError, EOFError, ValueError):
            _name2id = {}
        cfg._name2id = _name2id
    id = _name2id.get(searchName, None)
    if id is None:
        for userid in getUserList(request):
            name = User(request, id=userid).name
            _name2id[name] = userid
        cfg._name2id = _name2id
        arena = 'user'
        key = 'name2id'
        cache = caching.CacheEntry(request, arena, key, scope='wiki')
        cache.update(pickle.dumps(_name2id, PICKLE_PROTOCOL))
        id = _name2id.get(searchName, None)
    return id


def getUserIdentification(request, username=None):
    """ 
    Return user name or IP or '<unknown>' indicator.
    
    @param request: the request object
    @param username: (optional) user name
    @rtype: string
    @return: user name or IP or unknown indicator
    """
    _ = request.getText

    if username is None:
        username = request.user.name

    return username or (request.cfg.show_hosts and request.remote_addr) or _("<unknown>")


def encodePassword(pwd, charset='utf-8'):
    """ Encode a cleartext password

    Compatible to Apache htpasswd SHA encoding.

    When using different encoding than 'utf-8', the encoding might fail
    and raise UnicodeError.

    @param pwd: the cleartext password, (unicode)
    @param charset: charset used to encode password, used only for
        compatibility with old passwords generated on moin-1.2.
    @rtype: string
    @return: the password in apache htpasswd compatible SHA-encoding,
        or None
    """
    import base64

    # Might raise UnicodeError, but we can't do anything about it here,
    # so let the caller handle it.
    pwd = pwd.encode(charset)

    pwd = sha.new(pwd).digest()
    pwd = '{SHA}' + base64.encodestring(pwd).rstrip()
    return pwd


def normalizeName(name):
    """ Make normalized user name

    Prevent impersonating another user with names containing leading,
    trailing or multiple whitespace, or using invisible unicode
    characters.

    Prevent creating user page as sub page, because '/' is not allowed
    in user names.

    Prevent using ':' and ',' which are reserved by acl.
    
    @param name: user name, unicode
    @rtype: unicode
    @return: user name that can be used in acl lines
    """
    username_allowedchars = "'@.-_" # ' for names like O'Brian or email addresses.
                                    # "," and ":" must not be allowed (ACL delimiters).
                                    # We also allow _ in usernames for nicer URLs.
    # Strip non alpha numeric characters (except username_allowedchars), keep white space
    name = ''.join([c for c in name if c.isalnum() or c.isspace() or c in username_allowedchars])

    # Normalize white space. Each name can contain multiple 
    # words separated with only one space.
    name = ' '.join(name.split())

    return name


def isValidName(request, name):
    """ Validate user name

    @param name: user name, unicode
    """
    normalized = normalizeName(name)
    return (name == normalized) and not wikiutil.isGroupPage(request, name)


def encodeList(items):
    """ Encode list of items in user data file

    Items are separated by '\t' characters.
    
    @param items: list unicode strings
    @rtype: unicode
    @return: list encoded as unicode
    """
    line = []
    for item in items:
        item = item.strip()
        if not item:
            continue
        line.append(item)

    line = '\t'.join(line)
    return line


def decodeList(line):
    """ Decode list of items from user data file
    
    @param line: line containing list of items, encoded with encodeList
    @rtype: list of unicode strings
    @return: list of items in encoded in line
    """
    items = []
    for item in line.split('\t'):
        item = item.strip()
        if not item:
            continue
        items.append(item)
    return items


class User:
    """A MoinMoin User"""

    def __init__(self, request, id=None, name="", password=None, auth_username="", **kw):
        """ Initialize User object
        
        @param request: the request object
        @param id: (optional) user ID
        @param name: (optional) user name
        @param password: (optional) user password
        @param auth_username: (optional) already authenticated user name
                              (e.g. when using http basic auth)
        @keyword auth_method: method that was used for authentication,
                              default: 'internal'
        @keyword auth_attribs: tuple of user object attribute names that are
                               determined by auth method and should not be
                               changed by UserPreferences form, default: ().
                               First tuple element was used for authentication.
        """
        self._cfg = request.cfg
        self.valid = 0
        self.trusted = 0
        self.id = id
        self.auth_username = auth_username
        self.auth_method = kw.get('auth_method', 'internal')
        self.auth_attribs = kw.get('auth_attribs', ())

        # create some vars automatically
        self.__dict__.update(self._cfg.user_form_defaults)

        if name:
            self.name = name
        elif auth_username: # this is needed for user_autocreate
            self.name = auth_username

        # create checkbox fields (with default 0)
        for key, label in self._cfg.user_checkbox_fields:
            setattr(self, key, self._cfg.user_checkbox_defaults.get(key, 0))

        self.enc_password = ""
        if password:
            if password.startswith('{SHA}'):
                self.enc_password = password
            else:
                try:
                    self.enc_password = encodePassword(password)
                except UnicodeError:
                    pass # Should never happen

        #self.edit_cols = 80
        self.tz_offset = int(float(self._cfg.tz_offset) * 3600)
        self.language = ""
        self.date_fmt = ""
        self.datetime_fmt = ""
        self.quicklinks = []
        self.subscribed_pages = []
        self.theme_name = self._cfg.theme_default
        self.editor_default = self._cfg.editor_default
        self.editor_ui = self._cfg.editor_ui
        self.last_saved = str(time.time())

        # attrs not saved to profile
        self._request = request
        self._trail = []

        # we got an already authenticated username:
        check_pass = 0
        if not self.id and self.auth_username:
            self.id = getUserId(request, self.auth_username)
            if not password is None:
                check_pass = 1
        if self.id:
            self.load_from_id(check_pass)
            if self.name == self.auth_username:
                self.trusted = 1
        elif self.name:
            self.id = getUserId(self._request, self.name)
            if self.id:
                self.load_from_id(1)
            else:
                self.id = self.make_id()
        else:
            self.id = self.make_id()

        # "may" so we can say "if user.may.read(pagename):"
        if self._cfg.SecurityPolicy:
            self.may = self._cfg.SecurityPolicy(self)
        else:
            from security import Default
            self.may = Default(self)

        if self.language and not self.language in i18n.wikiLanguages():
            self.language = 'en'

    def __repr__(self):
        return "<%s.%s at 0x%x name:%r valid:%r>" % (
            self.__class__.__module__, self.__class__.__name__,
            id(self), self.name, self.valid)

    def make_id(self):
        """ make a new unique user id """
        #!!! this should probably be a hash of REMOTE_ADDR, HTTP_USER_AGENT
        # and some other things identifying remote users, then we could also
        # use it reliably in edit locking
        from random import randint
        return "%s.%d" % (str(time.time()), randint(0, 65535))

    def create_or_update(self, changed=False):
        """ Create or update a user profile

        @param changed: bool, set this to True if you updated the user profile values
        """
        if self._cfg.user_autocreate:
            if not self.valid and not self.disabled or changed: # do we need to save/update?
                self.save() # yes, create/update user profile

    def __filename(self):
        """ Get filename of the user's file on disk
        
        @rtype: string
        @return: full path and filename of user account file
        """
        return os.path.join(self._cfg.user_dir, self.id or "...NONE...")

    def __bookmark_filename(self):
        if self._cfg.interwikiname:
            return (self.__filename() + "." + self._cfg.interwikiname +
                    ".bookmark")
        else:
            return self.__filename() + ".bookmark"

    def exists(self):
        """ Do we have a user account for this user?
        
        @rtype: bool
        @return: true, if we have a user account
        """
        return os.path.exists(self.__filename())

    def load_from_id(self, check_pass=0):
        """ Load user account data from disk.

        Can only load user data if the id number is already known.

        This loads all member variables, except "id" and "valid" and
        those starting with an underscore.
        
        @param check_pass: If 1, then self.enc_password must match the
                           password in the user account file.
        """
        if not self.exists():
            return

        data = codecs.open(self.__filename(), "r", config.charset).readlines()
        user_data = {'enc_password': ''}
        for line in data:
            if line[0] == '#':
                continue

            try:
                key, val = line.strip().split('=', 1)
                if key not in self._cfg.user_transient_fields and key[0] != '_':
                    # Decode list values
                    if key in ['quicklinks', 'subscribed_pages']:
                        val = decodeList(val)
                    user_data[key] = val
            except ValueError:
                pass

        # Validate data from user file. In case we need to change some
        # values, we set 'changed' flag, and later save the user data.
        changed = 0

        if check_pass:
            # If we have no password set, we don't accept login with username
            if not user_data['enc_password']:
                return
            # Check for a valid password, possibly changing encoding
            valid, changed = self._validatePassword(user_data)
            if not valid:
                return
            else:
                self.trusted = 1

        # Remove ignored checkbox values from user data
        for key, label in self._cfg.user_checkbox_fields:
            if user_data.has_key(key) and key in self._cfg.user_checkbox_disable:
                del user_data[key]

        # Copy user data into user object
        for key, val in user_data.items():
            vars(self)[key] = val

        self.tz_offset = int(self.tz_offset)

        # Remove old unsupported attributes from user data file.
        remove_attributes = ['passwd', 'show_emoticons']
        for attr in remove_attributes:
            if hasattr(self, attr):
                delattr(self, attr)
                changed = 1

        # make sure checkboxes are boolean
        for key, label in self._cfg.user_checkbox_fields:
            try:
                setattr(self, key, int(getattr(self, key)))
            except ValueError:
                setattr(self, key, 0)

        # convert (old) hourly format to seconds
        if -24 <= self.tz_offset and self.tz_offset <= 24:
            self.tz_offset = self.tz_offset * 3600

        # clear trail
        self._trail = []

        if not self.disabled:
            self.valid = 1

        # If user data has been changed, save fixed user data.
        if changed:
            self.save()

    def _validatePassword(self, data):
        """ Try to validate user password

        This is a private method and should not be used by clients.

        In pre 1.3, the wiki used some 8 bit charset. The user password
        was entered in this 8 bit password and passed to
        encodePassword. So old passwords can use any of the charset
        used.

        In 1.3, we use unicode internally, so we encode the password in
        encodePassword using utf-8.

        When we compare passwords we must compare with same encoding, or
        the passwords will not match. We don't know what encoding the
        password on the user file uses. We may ask the wiki admin to put
        this into the config, but he may be wrong.

        The way chosen is to try to encode and compare passwords using
        all the encoding that were available on 1.2, until we get a
        match, which means that the user is valid.

        If we get a match, we replace the user password hash with the
        utf-8 encoded version, and next time it will match on first try
        as before. The user password did not change, this change is
        completely transparent for the user. Only the sha digest will
        change.

        @param data: dict with user data
        @rtype: 2 tuple (bool, bool)
        @return: password is valid, password did change
        """
        # First try with default encoded password. Match only non empty
        # passwords. (require non empty enc_password)
        if self.enc_password and self.enc_password == data['enc_password']:
            return True, False

        # Try to match using one of pre 1.3 8 bit charsets

        # Get the clear text password from the form (require non empty
        # password)
        password = self._request.form.get('password', [None])[0]
        if not password:
            return False, False

        # First get all available pre13 charsets on this system
        pre13 = ['iso-8859-1', 'iso-8859-2', 'euc-jp', 'gb2312', 'big5', ]
        available = []
        for charset in pre13:
            try:
                encoder = codecs.getencoder(charset)
                available.append(charset)
            except LookupError:
                pass # missing on this system

        # Now try to match the password
        for charset in available:
            # Try to encode, failure is expected
            try:
                enc_password = encodePassword(password, charset=charset)
            except UnicodeError:
                continue

            # And match (require non empty enc_password)
            if enc_password and enc_password == data['enc_password']:
                # User password match - replace the user password in the
                # file with self.password
                data['enc_password'] = self.enc_password
                return True, True

        # No encoded password match, this must be wrong password
        return False, False

    def save(self):
        """ Save user account data to user account file on disk.

        This saves all member variables, except "id" and "valid" and
        those starting with an underscore.
        """
        if not self.id:
            return

        user_dir = self._cfg.user_dir
        filesys.makeDirs(user_dir)

        self.last_saved = str(time.time())

        # !!! should write to a temp file here to avoid race conditions,
        # or even better, use locking

        data = codecs.open(self.__filename(), "w", config.charset)
        data.write("# Data saved '%s' for id '%s'\n" % (
            time.strftime(self._cfg.datetime_fmt, time.localtime(time.time())),
            self.id))
        attrs = vars(self).items()
        attrs.sort()
        for key, value in attrs:
            if key not in self._cfg.user_transient_fields and key[0] != '_':
                # Encode list values
                if key in ['quicklinks', 'subscribed_pages']:
                    value = encodeList(value)
                line = u"%s=%s\n" % (key, unicode(value))
                data.write(line)
        data.close()

        if not self.disabled:
            self.valid = 1

    # -----------------------------------------------------------------
    # Time and date formatting

    def getTime(self, tm):
        """ Get time in user's timezone.
        
        @param tm: time (UTC UNIX timestamp)
        @rtype: int
        @return: tm tuple adjusted for user's timezone
        """
        return timefuncs.tmtuple(tm + self.tz_offset)


    def getFormattedDate(self, tm):
        """ Get formatted date adjusted for user's timezone.

        @param tm: time (UTC UNIX timestamp)
        @rtype: string
        @return: formatted date, see cfg.date_fmt
        """
        date_fmt = self.date_fmt or self._cfg.date_fmt
        return time.strftime(date_fmt, self.getTime(tm))


    def getFormattedDateTime(self, tm):
        """ Get formatted date and time adjusted for user's timezone.

        @param tm: time (UTC UNIX timestamp)
        @rtype: string
        @return: formatted date and time, see cfg.datetime_fmt
        """
        datetime_fmt = self.datetime_fmt or self._cfg.datetime_fmt
        return time.strftime(datetime_fmt, self.getTime(tm))

    # -----------------------------------------------------------------
    # Bookmark

    def setBookmark(self, tm):
        """ Set bookmark timestamp.
        
        @param tm: timestamp
        """
        if self.valid:
            bm_fn = self.__bookmark_filename()
            bmfile = open(bm_fn, "w")
            bmfile.write(str(tm)+"\n")
            bmfile.close()

    def getBookmark(self):
        """ Get bookmark timestamp.
        
        @rtype: int
        @return: bookmark timestamp or None
        """
        bm = None
        bm_fn = self.__bookmark_filename()

        if self.valid and os.path.exists(bm_fn):
            try:
                bm = long(open(bm_fn, 'r').readline()) # must be long for py 2.2
            except (OSError, ValueError):
                pass
        return bm

    def delBookmark(self):
        """ Removes bookmark timestamp.

        @rtype: int
        @return: 0 on success, 1 on failure
        """
        bm_fn = self.__bookmark_filename()
        if self.valid:
            if os.path.exists(bm_fn):
                try:
                    os.unlink(bm_fn)
                except OSError:
                    return 1
            return 0
        return 1

    # -----------------------------------------------------------------
    # Subscribe

    def getSubscriptionList(self):
        """ Get list of pages this user has subscribed to
        
        @rtype: list
        @return: pages this user has subscribed to
        """
        return self.subscribed_pages

    def isSubscribedTo(self, pagelist):
        """ Check if user subscription matches any page in pagelist.
        
        The subscription list may contain page names or interwiki page
        names. e.g 'Page Name' or 'WikiName:Page_Name'
        
        TODO: check if its fast enough when calling with many users
        from page.getSubscribersList()
        
        @param pagelist: list of pages to check for subscription
        @rtype: bool
        @return: if user is subscribed any page in pagelist
        """
        if not self.valid:
            return False

        import re
        # Create a new list with both names and interwiki names.
        pages = pagelist[:]
        if self._cfg.interwikiname:
            pages += [self._interWikiName(pagename) for pagename in pagelist]
        # Create text for regular expression search
        text = '\n'.join(pages)

        for pattern in self.getSubscriptionList():
            # Try simple match first
            if pattern in pages:
                return True
            # Try regular expression search, skipping bad patterns
            try:
                pattern = re.compile(r'^%s$' % pattern, re.M)
            except re.error:
                continue
            if pattern.search(text):
                return True

        return False

    def subscribe(self, pagename):
        """ Subscribe to a wiki page.

        To enable shared farm users, if the wiki has an interwiki name,
        page names are saved as interwiki names.

        @param pagename: name of the page to subscribe
        @type pagename: unicode
        @rtype: bool
        @return: if page was subscribed
        """
        if self._cfg.interwikiname:
            pagename = self._interWikiName(pagename)

        if pagename not in self.subscribed_pages:
            self.subscribed_pages.append(pagename)
            self.save()
            return True

        return False

    def unsubscribe(self, pagename):
        """ Unsubscribe a wiki page.

        Try to unsubscribe by removing non-interwiki name (leftover
        from old use files) and interwiki name from the subscription
        list.

        Its possible that the user will be subscribed to a page by more
        then one pattern. It can be both pagename and interwiki name,
        or few patterns that all of them match the page. Therefore, we
        must check if the user is still subscribed to the page after we
        try to remove names from the list.

        TODO: should we remove non-interwiki subscription? what if the
        user want to subscribe to the same page in multiple wikis?

        @param pagename: name of the page to subscribe
        @type pagename: unicode
        @rtype: bool
        @return: if unsubscrieb was successful. If the user has a
            regular expression that match, it will always fail.
        """
        changed = False
        if pagename in self.subscribed_pages:
            self.subscribed_pages.remove(pagename)
            changed = True

        interWikiName = self._interWikiName(pagename)
        if interWikiName and interWikiName in self.subscribed_pages:
            self.subscribed_pages.remove(interWikiName)
            changed = True

        if changed:
            self.save()
        return not self.isSubscribedTo([pagename])

    # -----------------------------------------------------------------
    # Quicklinks

    def getQuickLinks(self):
        """ Get list of pages this user wants in the navibar

        @rtype: list
        @return: quicklinks from user account
        """
        return self.quicklinks

    def isQuickLinkedTo(self, pagelist):
        """ Check if user quicklink matches any page in pagelist.
        
        @param pagelist: list of pages to check for quicklinks
        @rtype: bool
        @return: if user has quicklinked any page in pagelist
        """
        if not self.valid:
            return False

        for pagename in pagelist:
            if pagename in self.quicklinks:
                return True
            interWikiName = self._interWikiName(pagename)
            if interWikiName and interWikiName in self.quicklinks:
                return True

        return False

    def addQuicklink(self, pagename):
        """ Adds a page to the user quicklinks 
        
        If the wiki has an interwiki name, all links are saved as
        interwiki names. If not, as simple page name.

        @param pagename: page name
        @type pagename: unicode
        @rtype: bool
        @return: if pagename was added
        """
        changed = False
        interWikiName = self._interWikiName(pagename)
        if interWikiName:
            if pagename in self.quicklinks:
                self.quicklinks.remove(pagename)
                changed = True
            if interWikiName not in self.quicklinks:
                self.quicklinks.append(interWikiName)
                changed = True
        else:
            if pagename not in self.quicklinks:
                self.quicklinks.append(pagename)
                changed = True

        if changed:
            self.save()
        return changed

    def removeQuicklink(self, pagename):
        """ Remove a page from user quicklinks 
        
        Remove both interwiki and simple name from quicklinks.
        
        @param pagename: page name
        @type pagename: unicode
        @rtype: bool
        @return: if pagename was removed
        """
        changed = False
        interWikiName = self._interWikiName(pagename)
        if interWikiName and interWikiName in self.quicklinks:
            self.quicklinks.remove(interWikiName)
            changed = True
        if pagename in self.quicklinks:
            self.quicklinks.remove(pagename)
            changed = True

        if changed:
            self.save()
        return changed

    def _interWikiName(self, pagename):
        """ Return the inter wiki name of a page name 

        @param pagename: page name
        @type pagename: unicode
        """
        if not self._cfg.interwikiname:
            return None

        return "%s:%s" % (self._cfg.interwikiname, pagename)

    # -----------------------------------------------------------------
    # Trail

    def addTrail(self, pagename):
        """ Add page to trail.
        
        @param pagename: the page name to add to the trail
        """
        # TODO: acquire lock here, so multiple processes don't clobber
        # each one trail.

        if self.valid and (self.show_page_trail or self.remember_last_visit):
            # load trail if not known
            self.getTrail()

            # Add only existing pages that the user may read
            if self._request:
                from MoinMoin.Page import Page
                page = Page(self._request, pagename)
                if not (page.exists() and
                        self._request.user.may.read(page.page_name)):
                    return

            # Save interwiki links internally
            if self._cfg.interwikiname:
                pagename = self._interWikiName(pagename)

            # Don't append tail to trail ;)
            if self._trail and self._trail[-1] == pagename:
                return

            # Append new page, limiting the length
            self._trail = [p for p in self._trail if p != pagename]
            self._trail = self._trail[-(self._cfg.trail_size-1):]
            self._trail.append(pagename)
            self.saveTrail()

        # TODO: release lock here

    def saveTrail(self):
        """ Save trail file

        Save using one write call, which should be fine in most cases,
        but will fail in rare cases without real file locking.
        """
        data = '\n'.join(self._trail) + '\n'
        path = self.__filename() + ".trail"
        try:
            file = codecs.open(path, "w", config.charset)
            try:
                file.write(data)
            finally:
                file.close()
        except (IOError, OSError), err:
            self._request.log("Can't save trail file: %s" % str(err))

    def getTrail(self):
        """ Return list of recently visited pages.
        
        @rtype: list
        @return: pages in trail
        """
        if self.valid and (self.show_page_trail or self.remember_last_visit) \
                and not self._trail \
                and os.path.exists(self.__filename() + ".trail"):
            try:
                trail = codecs.open(self.__filename() + ".trail", 'r', config.charset).readlines()
            except (OSError, ValueError):
                trail = []
            trail = [t.strip() for t in trail]
            trail = [t for t in trail if t]
            self._trail = trail[-self._cfg.trail_size:]

        return self._trail

    # -----------------------------------------------------------------
    # Other

    def isCurrentUser(self):
        return self._request.user.name == self.name

    def isSuperUser(self):
        superusers = self._request.cfg.superuser
        assert isinstance(superusers, (list, tuple))
        return self.valid and self.name and self.name in superusers

    def host(self):
        """ Return user host """
        _ = self._request.getText
        host = self.isCurrentUser() and self._cfg.show_hosts and self._request.remote_addr
        return host or _("<unknown>")

    def wikiHomeLink(self):
        """ return wiki markup usable as a link to the user homepage,
            it doesn't matter whether it already exists or not.
        """
        wikiname, pagename = wikiutil.getInterwikiHomePage(self._request, self.name)
        if wikiname == 'Self':
            if wikiutil.isStrictWikiname(self.name):
                markup = pagename
            else:
                markup = '["%s"]' % pagename
        else:
            markup = '%s:%s' % (wikiname, pagename) # TODO: support spaces in pagename
        return markup

    def signature(self):
        """ Return user signature using wiki markup
        
        Users sign with a link to their homepage.
        Visitors return their host address.
        
        TODO: The signature use wiki format only, for example, it will
        not create a link when using rst format. It will also break if
        we change wiki syntax.
        """
        if self.name:
            return self.wikiHomeLink()
        else:
            return self.host()

    def mailAccountData(self, cleartext_passwd=None):
        from MoinMoin.mail import sendmail
        from MoinMoin.wikiutil import getSysPage
        _ = self._request.getText

        if not self.enc_password: # generate pw if there is none yet
            from random import randint
            import base64

            charset = 'utf-8'
            pwd = "%s%d" % (str(time.time()), randint(0, 65535))
            pwd = pwd.encode(charset)

            pwd = sha.new(pwd).digest()
            pwd = '{SHA}%s' % base64.encodestring(pwd).rstrip()

            self.enc_password = pwd
            self.save()

        text = '\n' + _("""\
Login Name: %s

Login Password: %s

Login URL: %s/%s?action=login
""", formatted=False) % (
                        self.name, self.enc_password, self._request.getBaseURL(), getSysPage(self._request, 'UserPreferences').page_name)

        text = _("""\
Somebody has requested to submit your account data to this email address.

If you lost your password, please use the data below and just enter the
password AS SHOWN into the wiki's password form field (use copy and paste
for that).

After successfully logging in, it is of course a good idea to set a new and known password.
""", formatted=False) + text


        subject = _('[%(sitename)s] Your wiki account data',
                    formatted=False) % {'sitename': self._cfg.sitename or "Wiki"}
        mailok, msg = sendmail.sendmail(self._request, [self.email], subject,
                                    text, mail_from=self._cfg.mail_from)
        return msg