origin-relative-ref = path-absolute [ "?" query ] [ "#" fragment ]

        with the exception that '%' escapes are not validated and '#' is

        allowed inside the fragment part.

        """

        return _re.match(came_from) is not None

    def index(self):

        c.came_from = safe_str(request.GET.get('came_from', ''))

        if c.came_from:

            if not self._validate_came_from(c.came_from):

                log.error('Invalid came_from (not server-relative): %r', c.came_from)

                raise HTTPBadRequest()

        else:

            c.came_from = url('home')

        if request.POST:

            # import Login Form validator class

            login_form = LoginForm()()

            try:

                c.form_result = login_form.to_python(dict(request.POST))

                # form checks for username/password, now we're authenticated

                username = c.form_result['username']

                user = User.get_by_username_or_email(username, case_insensitive=True)

            except formencode.Invalid as errors:

                defaults = errors.value

                # remove password from filling in form again

                defaults.pop('password', None)

                return htmlfill.render(

                    render('/login.html'),

                    defaults=errors.value,

                    errors=errors.error_dict or {},

                    prefix_error=False,

                    encoding="UTF-8",

                    force_defaults=False)

            except UserCreationError as e:

                # container auth or other auth functions that create users on

                # the fly can throw this exception signaling that there's issue

                # with user creation, explanation should be provided in

                # Exception itself

                h.flash(e, 'error')

            else:

                log_in_user(user, c.form_result['remember'],

                    is_external_auth=False)

                raise HTTPFound(location=c.came_from)

        else:

            # redirect if already logged in

                raise HTTPFound(location=c.came_from)

        return render('/login.html')

    @HasPermissionAnyDecorator('hg.admin', 'hg.register.auto_activate',

                               'hg.register.manual_activate')

    def register(self):

        def_user_perms = AuthUser(dbuser=User.get_default_user()).permissions['global']

        c.auto_active = 'hg.register.auto_activate' in def_user_perms

        settings = Setting.get_app_settings()

        captcha_private_key = settings.get('captcha_private_key')

        c.captcha_active = bool(captcha_private_key)

        c.captcha_public_key = settings.get('captcha_public_key')

        if request.POST:

            register_form = RegisterForm()()

            try:

                form_result = register_form.to_python(dict(request.POST))

                form_result['active'] = c.auto_active

                if c.captcha_active:

                    from kallithea.lib.recaptcha import submit

                    response = submit(request.POST.get('g-recaptcha-response'),

                                      private_key=captcha_private_key,

                                      remoteip=request.ip_addr)

                    if not response.is_valid:

                        _value = form_result

                        _msg = _('Bad captcha')

                        error_dict = {'recaptcha_field': _msg}

                        raise formencode.Invalid(_msg, _value, None,

                                                 error_dict=error_dict)

                UserModel().create_registration(form_result)

                h.flash(_('You have successfully registered with %s') % (c.site_name or 'Kallithea'),

                        category='success')

                Session().commit()

                raise HTTPFound(location=url('login_home'))

            except formencode.Invalid as errors:

                return htmlfill.render(

                    render('/register.html'),

                    defaults=errors.value,

                    errors=errors.error_dict or {},

                    prefix_error=False,

                    encoding="UTF-8",

                    force_defaults=False)

            except UserCreationError as e:

                # container auth or other auth functions that create users on

        h.flash(message, category='warning')

    p = request.path_qs

    log.debug('Redirecting to login page, origin: %s', p)

    return HTTPFound(location=url('login_home', came_from=p))

# Use as decorator

class LoginRequired(object):

    """Client must be logged in as a valid User, or we'll redirect to the login

    page.

    If the "default" user is enabled and allow_default_user is true, that is

    considered valid too.

    Also checks that IP address is allowed.

    """

    def __init__(self, allow_default_user=False):

        self.allow_default_user = allow_default_user

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        controller = fargs[0]

        user = request.authuser

        loc = "%s:%s" % (controller.__class__.__name__, func.__name__)

        log.debug('Checking access for user %s @ %s', user, loc)

        # Check if we used an API key to authenticate.

        if user.authenticating_api_key is not None:

            log.info('user %s authenticated with API key ****%s @ %s',

                     user, user.authenticating_api_key[-4:], loc)

            return func(*fargs, **fkwargs)

        # CSRF protection: Whenever a request has ambient authority (whether

        # through a session cookie or its origin IP address), it must include

        # the correct token, unless the HTTP method is GET or HEAD (and thus

        # guaranteed to be side effect free. In practice, the only situation

        # where we allow side effects without ambient authority is when the

        # authority comes from an API key; and that is handled above.

        if request.method not in ['GET', 'HEAD']:

            token = request.POST.get(secure_form.token_key)

            if not token or token != secure_form.authentication_token():

                log.error('CSRF check failed')

                raise HTTPForbidden()

        # regular user authentication

            if self.allow_default_user:

                log.info('default user @ %s', loc)

                return func(*fargs, **fkwargs)

            log.info('default user is not accepted here @ %s', loc)

        raise _redirect_to_login()

# Use as decorator

class NotAnonymous(object):

    """Ensures that client is not logged in as the "default" user, and

    redirects to the login page otherwise. Must be used together with

    LoginRequired."""

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        cls = fargs[0]

        user = request.authuser

        log.debug('Checking that user %s is not anonymous @%s', user.username, cls)

        if user.is_default_user:

            raise _redirect_to_login(_('You need to be a registered user to '

                                       'perform this action'))

        else:

            return func(*fargs, **fkwargs)

class _PermsDecorator(object):

    """Base class for controller decorators with multiple permissions"""

    def __init__(self, *required_perms):

        self.required_perms = required_perms # usually very short - a list is thus fine

    def __call__(self, func):

        return decorator(self.__wrapper, func)

    def __wrapper(self, func, *fargs, **fkwargs):

        cls = fargs[0]

        user = request.authuser

        log.debug('checking %s permissions %s for %s %s',

          self.__class__.__name__, self.required_perms, cls, user)

        if self.check_permissions(user):

            log.debug('Permission granted for %s %s', cls, user)

            return func(*fargs, **fkwargs)

        else:

            log.info('Permission denied for %s %s', cls, user)

            if user.is_default_user:

                raise _redirect_to_login(_('You need to be signed in to view this page'))