# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb is distributed in the hope that it will be useful, but WITHOUT

# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

"""CubicWeb web client application object"""

from __future__ import with_statement

__docformat__ = "restructuredtext en"

import sys

from time import clock, time

from contextlib import contextmanager

from logilab.common.deprecation import deprecated

from rql import BadRQLQuery

from cubicweb import set_log_methods, cwvreg

from cubicweb import (

    ValidationError, Unauthorized, AuthenticationError, NoSelectableObject,

    BadConnectionId, CW_EVENT_MANAGER)

from cubicweb.dbapi import DBAPISession, anonymous_session

from cubicweb.web import LOGGER, component

from cubicweb.web import (

    StatusResponse, DirectResponse, Redirect, NotFound, LogOut,

    RemoteCallFailed, InvalidSession, RequestError)

# make session manager available through a global variable so the debug view can

# print information about web session

SESSION_MANAGER = None

@contextmanager

def anonymized_request(req):

    orig_session = req.session

    req.set_session(anonymous_session(req.vreg))

    try:

        yield req

    finally:

        req.set_session(orig_session)

class AbstractSessionManager(component.Component):

    """manage session data associated to a session identifier"""

    __regid__ = 'sessionmanager'

    def __init__(self, vreg):

        self.session_time = vreg.config['http-session-time'] or None

        self.authmanager = vreg['components'].select('authmanager', vreg=vreg)

        interval = (self.session_time or 0) / 2.

        if vreg.config.anonymous_user() is not None:

            self.cleanup_anon_session_time = vreg.config['cleanup-anonymous-session-time'] or 5 * 60

            assert self.cleanup_anon_session_time > 0

            if self.session_time is not None:

                self.cleanup_anon_session_time = min(self.session_time,

                                                     self.cleanup_anon_session_time)

            interval = self.cleanup_anon_session_time / 2.

        # we don't want to check session more than once every 5 minutes

        self.clean_sessions_interval = max(5 * 60, interval)

    def clean_sessions(self):

        """cleanup sessions which has not been unused since a given amount of

        time. Return the number of sessions which have been closed.

        """

        self.debug('cleaning http sessions')

        session_time = self.session_time

        closed, total = 0, 0

        for session in self.current_sessions():

            total += 1

            try:

                last_usage_time = session.cnx.check()

            except AttributeError:

                last_usage_time = session.mtime

            except BadConnectionId:

                self.close_session(session)

                closed += 1

            else:

                no_use_time = (time() - last_usage_time)

                if session.anonymous_session:

                    if no_use_time >= self.cleanup_anon_session_time:

                        self.close_session(session)

                        closed += 1

                elif session_time is not None and no_use_time >= session_time:

                    self.close_session(session)

                    closed += 1

        return closed, total - closed

    def current_sessions(self):

        """return currently open sessions"""

        raise NotImplementedError()

    def get_session(self, req, sessionid):

        """return existing session for the given session identifier"""

        raise NotImplementedError()

    def open_session(self, req):

        """open and return a new session for the given request. The session is

        also bound to the request.

        raise :exc:`cubicweb.AuthenticationError` if authentication failed

        (no authentication info found or wrong user/password)

        """

        raise NotImplementedError()

    def close_session(self, session):

        """close session on logout or on invalid session detected (expired out,

        corrupted...)

        """

        raise NotImplementedError()

class AbstractAuthenticationManager(component.Component):

    """authenticate user associated to a request and check session validity"""

    __regid__ = 'authmanager'

    def __init__(self, vreg):

        self.vreg = vreg

    def validate_session(self, req, session):

        """check session validity, reconnecting it to the repository if the

        associated connection expired in the repository side (hence the

        necessity for this method).

        raise :exc:`InvalidSession` if session is corrupted for a reason or

        another and should be closed

        """

        raise NotImplementedError()

    def authenticate(self, req):

        """authenticate user using connection information found in the request,

        and return corresponding a :class:`~cubicweb.dbapi.Connection` instance,

        as well as login and authentication information dictionary used to open

        the connection.

        raise :exc:`cubicweb.AuthenticationError` if authentication failed

        (no authentication info found or wrong user/password)

        """

        raise NotImplementedError()

class CookieSessionHandler(object):

    """a session handler using a cookie to store the session identifier"""

    def __init__(self, appli):

        self.vreg = appli.vreg

        self.session_manager = self.vreg['components'].select('sessionmanager',

                                                              vreg=self.vreg)

        global SESSION_MANAGER

        SESSION_MANAGER = self.session_manager

        if self.vreg.config.mode != 'test':

            # don't try to reset session manager during test, this leads to

            # weird failures when running multiple tests

            CW_EVENT_MANAGER.bind('after-registry-reload',

                                  self.reset_session_manager)

    def reset_session_manager(self):

        data = self.session_manager.dump_data()

        self.session_manager = self.vreg['components'].select('sessionmanager',

                                                              vreg=self.vreg)

        self.session_manager.restore_data(data)

        global SESSION_MANAGER

        SESSION_MANAGER = self.session_manager

    @property

    def clean_sessions_interval(self):

        return self.session_manager.clean_sessions_interval

    def clean_sessions(self):

        """cleanup sessions which has not been unused since a given amount of

        time

        """

        self.session_manager.clean_sessions()

    def session_cookie(self, req):

        """return a string giving the name of the cookie used to store the

        session identifier.

        """

        if req.https:

            return '__%s_https_session' % self.vreg.config.appid

        return '__%s_session' % self.vreg.config.appid

    def set_session(self, req):

        """associate a session to the request

        Session id is searched from :

        - # form variable

        - cookie

        if no session id is found, open a new session for the connected user

        or request authentification as needed

        :raise Redirect: if authentication has occurred and succeed

        """

        cookie = req.get_cookie()

        sessioncookie = self.session_cookie(req)

        try:

            sessionid = str(cookie[sessioncookie].value)

        except KeyError: # no session cookie

            session = self.open_session(req)

        else:

            try:

                session = self.get_session(req, sessionid)

            except InvalidSession:

                # try to open a new session, so we get an anonymous session if

                # allowed

                session = self.open_session(req)

            else:

                if not session.cnx:

                    # session exists but is not bound to a connection. We should

                    # try to authenticate

                    loginsucceed = False

                    try:

                        if self.open_session(req, allow_no_cnx=False):

                            loginsucceed = True

                    except Redirect:

                        # may be raised in open_session (by postlogin mechanism)

                        # on successful connection

                        loginsucceed = True

                        raise

                    except AuthenticationError:

                        # authentication failed, continue to use this session

                        req.set_session(session)

                    finally:

                        if loginsucceed:

                            # session should be replaced by new session created

                            # in open_session

                            self.session_manager.close_session(session)

    def get_session(self, req, sessionid):

        session = self.session_manager.get_session(req, sessionid)

        session.mtime = time()

        return session

    def open_session(self, req, allow_no_cnx=True):

        session = self.session_manager.open_session(req, allow_no_cnx=allow_no_cnx)

        sessioncookie = self.session_cookie(req)

        secure = req.https and req.base_url().startswith('https://')

        req.set_cookie(sessioncookie, session.sessionid,

                       maxage=None, secure=secure)

        if not session.anonymous_session:

            self.session_manager.postlogin(req)

        return session

    def logout(self, req, goto_url):

        """logout from the instance by cleaning the session and raising

        `AuthenticationError`

        """

        self.session_manager.close_session(req.session)

        req.remove_cookie(self.session_cookie(req))

        raise LogOut(url=goto_url)

    # these are overridden by set_log_methods below

    # only defining here to prevent pylint from complaining

    info = warning = error = critical = exception = debug = lambda msg,*a,**kw: None

class CubicWebPublisher(object):

    """the publisher is a singleton hold by the web frontend, and is responsible

    to publish HTTP request.

    """

    def __init__(self, config,

                 session_handler_fact=CookieSessionHandler,

                 vreg=None):

        self.info('starting web instance from %s', config.apphome)

        if vreg is None:

        self.vreg = vreg

        # connect to the repository and get instance's schema

        self.repo = config.repository(vreg)

        if not vreg.initialized:

            config.init_cubes(self.repo.get_cubes())

            vreg.init_properties(self.repo.properties())

            vreg.set_schema(self.repo.get_schema())

        # set the correct publish method

        if config['query-log-file']:

            from threading import Lock

            self._query_log = open(config['query-log-file'], 'a')

            self.publish = self.log_publish

            self._logfile_lock = Lock()

        else:

            self._query_log = None

            self.publish = self.main_publish

        # instantiate session and url resolving helpers

        self.session_handler = session_handler_fact(self)

        self.set_urlresolver()

        CW_EVENT_MANAGER.bind('after-registry-reload', self.set_urlresolver)

    def set_urlresolver(self):

        self.url_resolver = self.vreg['components'].select('urlpublisher',

                                                           vreg=self.vreg)

    def connect(self, req):

        """return a connection for a logged user object according to existing

        sessions (i.e. a new connection may be created or an already existing

        one may be reused

        """

        self.session_handler.set_session(req)

    # publish methods #########################################################

    def log_publish(self, path, req):

        """wrapper around _publish to log all queries executed for a given

        accessed path

        """

        try:

            return self.main_publish(path, req)

        finally:

            cnx = req.cnx

            if cnx:

                with self._logfile_lock:

                    try:

                        result = ['\n'+'*'*80]

                        result.append(req.url())

                        result += ['%s %s -- (%.3f sec, %.3f CPU sec)' % q

                                   for q in cnx.executed_queries]

                        cnx.executed_queries = []

                        self._query_log.write('\n'.join(result).encode(req.encoding))

                        self._query_log.flush()

                    except Exception:

                        self.exception('error while logging queries')

    def main_publish(self, path, req):

        """method called by the main publisher to process <path>

        should return a string containing the resulting page or raise a

        `NotFound` exception

        :type path: str

        :param path: the path part of the url to publish

        :type req: `web.Request`

        :param req: the request object

        :rtype: str

        :return: the result of the pusblished url

        """

        path = path or 'view'

        # don't log form values they may contains sensitive information

        self.info('publish "%s" (%s, form params: %s)',

                  path, req.session.sessionid, req.form.keys())

        # remove user callbacks on a new request (except for json controllers

        # to avoid callbacks being unregistered before they could be called)

        tstart = clock()

        commited = False

        try:

            try:

                ctrlid, rset = self.url_resolver.process(req, path)

                try:

                    controller = self.vreg['controllers'].select(ctrlid, req,

                                                                 appli=self)

                except NoSelectableObject:

                    if ctrlid == 'login':

                        raise Unauthorized(req._('log out first'))

                    raise Unauthorized(req._('not authorized'))

                req.update_search_state()

                result = controller.publish(rset=rset)

                if req.cnx:

                    # no req.cnx if anonymous aren't allowed and we are

                    # displaying some anonymous enabled view such as the cookie

                    # authentication form

                    req.cnx.commit()

                    commited = True

            except (StatusResponse, DirectResponse):

                if req.cnx:

                    req.cnx.commit()

                raise

            except (AuthenticationError, LogOut):

                raise

            except Redirect:

                # redirect is raised by edit controller when everything went fine,

                # so try to commit

                try:

                    if req.cnx:

                        txuuid = req.cnx.commit()

                        if txuuid is not None:

                            msg = u'<span class="undo">[<a href="%s">%s</a>]</span>' %(

                                req.build_url('undo', txuuid=txuuid), req._('undo'))

                            req.append_to_redirect_message(msg)

                except ValidationError, ex:

                    self.validation_error_handler(req, ex)

                except Unauthorized, ex: