# copyright 2003-2014 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"""

__docformat__ = "restructuredtext en"

import sys

from time import clock, time

from contextlib import contextmanager

from warnings import warn

import json

import httplib

from logilab.common.deprecation import deprecated

from rql import BadRQLQuery

from cubicweb import set_log_methods, cwvreg

from cubicweb import (

    ValidationError, Unauthorized, Forbidden,

    AuthenticationError, NoSelectableObject,

    CW_EVENT_MANAGER)

from cubicweb.repoapi import anonymous_cnx

from cubicweb.web import LOGGER, component, cors

from cubicweb.web import (

    StatusResponse, DirectResponse, Redirect, NotFound, LogOut,

    RemoteCallFailed, InvalidSession, RequestError, PublishException)

from cubicweb.web.request import CubicWebRequestBase

# 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_cnx = req.cnx

    anon_cnx = anonymous_cnx(orig_cnx.session.repo)

    req.set_cnx(anon_cnx)

    try:

        with anon_cnx:

            yield req

    finally:

        req.set_cnx(orig_cnx)

class CookieSessionHandler(object):

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

    def __init__(self, appli):

        self.repo = appli.repo

        self.vreg = appli.vreg

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

                                                              repo=self.repo)

        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',

                                                              repo=self.repo)

        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 get_session(self, req):

        """Return a session object corresponding to credentials held by the req

        Session id is searched from :

        - # form variable

        - cookie

        If no session id is found, try opening a new session with credentials

        found in the request.

        Raises AuthenticationError if no session can be found or created.

        """

        cookie = req.get_cookie()

        sessioncookie = self.session_cookie(req)

        try:

            sessionid = str(cookie[sessioncookie].value)

            session = self.get_session_by_id(req, sessionid)

        except (KeyError, InvalidSession): # no valid session cookie

            session = self.open_session(req)

        return session

    def get_session_by_id(self, req, sessionid):

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

        session.mtime = time()

        return session

    def open_session(self, req):

        session = self.session_manager.open_session(req)

        sessioncookie = self.session_cookie(req)

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

        req.set_cookie(sessioncookie, session.sessionid,

                       maxage=None, secure=secure, httponly=True)

        if not session.anonymous_session:

            self.session_manager.postlogin(req, session)

        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.

    The http server will call its main entry point ``application.handle_request``.

    .. automethod:: cubicweb.web.application.CubicWebPublisher.main_handle_request

    You have to provide both a repository and web-server config at

    initialization. In all in one instance both config will be the same.

    """

    def __init__(self, repo, config, session_handler_fact=CookieSessionHandler):

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

        self.repo = repo

        self.vreg = repo.vreg

        # get instance's schema

        if not self.vreg.initialized:

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

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

            self.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.handle_request = self.log_handle_request

            self._logfile_lock = Lock()

        else:

            self._query_log = None

            self.handle_request = self.main_handle_request

        # 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 get_session(self, req):

        """Return a session object corresponding to credentials held by the req

        May raise AuthenticationError.

        """

        return self.session_handler.get_session(req)

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

    def log_handle_request(self, req, path):

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

        accessed path

        """

        def wrap_set_cnx(func):

            def wrap_execute(cnx):

                orig_execute = cnx.execute

                def execute(rql, kwargs=None, build_descr=True):

                    tstart, cstart = time(), clock()

                    rset = orig_execute(rql, kwargs, build_descr=build_descr)

                    cnx.executed_queries.append((rql, kwargs, time() - tstart, clock() - cstart))

                    return rset

                return execute

            def set_cnx(cnx):

                func(cnx)

                cnx.execute = wrap_execute(cnx)

                cnx.executed_queries = []

            return set_cnx

        req.set_cnx = wrap_set_cnx(req.set_cnx)

        try:

            return self.main_handle_request(req, path)

        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_handle_request(self, req, path):

        """Process an http request

        Arguments are:

        - a Request object

        - path of the request object

        It returns the content of the http response. HTTP header and status are

        set on the Request object.

        """

        if not isinstance(req, CubicWebRequestBase):

            warn('[3.15] Application entry point arguments are now (req, path) '

                 'not (path, req)', DeprecationWarning, 2)

            req, path = path, req

        if req.authmode == 'http':

            # activate realm-based auth

            realm = self.vreg.config['realm']

            req.set_header('WWW-Authenticate', [('Basic', {'realm' : realm })], raw=False)

        content = ''

        try:

            try:

                session = self.get_session(req)

                from  cubicweb import repoapi

                cnx = repoapi.Connection(session)

                req.set_cnx(cnx)

            except AuthenticationError:

                # Keep the dummy session set at initialisation.

                # such session with work to an some extend but raise an

                # AuthenticationError on any database access.

                import contextlib

                @contextlib.contextmanager

                def dummy():

                    yield

                cnx = dummy()

                # XXX We want to clean up this approach in the future. But

                # several cubes like registration or forgotten password rely on

                # this principle.

            # nested try to allow LogOut to delegate logic to AuthenticationError

            # handler

            try:

                ### Try to generate the actual request content

                with cnx:

                    content = self.core_handle(req, path)

            # Handle user log-out

            except LogOut as ex:

                # When authentification is handled by cookie the code that

                # raised LogOut must has invalidated the cookie. We can just

                # reload the original url without authentification

                if self.vreg.config['auth-mode'] == 'cookie' and ex.url:

                    req.headers_out.setHeader('location', str(ex.url))

                if ex.status is not None:

                    req.status_out = httplib.SEE_OTHER

                # When the authentification is handled by http we must

                # explicitly ask for authentification to flush current http

                # authentification information

                else:

                    # Render "logged out" content.

                    # assignement to ``content`` prevent standard

                    # AuthenticationError code to overwrite it.

                    content = self.loggedout_content(req)

                    # let the explicitly reset http credential

                    raise AuthenticationError()

        except Redirect as ex:

            # authentication needs redirection (eg openid)

            content = self.redirect_handler(req, ex)

        # Wrong, absent or Reseted credential

        except AuthenticationError:

            # If there is an https url configured and

            # the request does not use https, redirect to login form

            https_url = self.vreg.config['https-url']

            if https_url and req.base_url() != https_url:

                req.status_out = httplib.SEE_OTHER

                req.headers_out.setHeader('location', https_url + 'login')

            else:

                # We assume here that in http auth mode the user *May* provide

                # Authentification Credential if asked kindly.

                if self.vreg.config['auth-mode'] == 'http':

                    req.status_out = httplib.UNAUTHORIZED

                # In the other case (coky auth) we assume that there is no way

                # for the user to provide them...

                # XXX But WHY ?

                else:

                    req.status_out = httplib.FORBIDDEN

                # If previous error handling already generated a custom content

                # do not overwrite it. This is used by LogOut Except

                # XXX ensure we don't actually serve content

                if not content:

                    content = self.need_login_content(req)

        return content

    def core_handle(self, req, path):

        """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

        """

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

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

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

        # 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:

            ### standard processing of the request

            try:

                # apply CORS sanity checks

                cors.process_request(req, self.vreg.config)

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

                try:

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

                                                                 appli=self)

                except NoSelectableObject:

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

                req.update_search_state()

                result = controller.publish(rset=rset)

            except cors.CORSPreflight:

                # Return directly an empty 200

                req.status_out = 200

                result = ''

            except StatusResponse as ex:

                warn('[3.16] StatusResponse is deprecated use req.status_out',

                     DeprecationWarning, stacklevel=2)

                result = ex.content

                req.status_out = ex.status

            except Redirect as ex:

                # Redirect may be raised by edit controller when everything went

                # fine, so attempt to commit

                result = self.redirect_handler(req, ex)

            if req.cnx:

                txuuid = req.cnx.commit()

                commited = True

                if txuuid is not None:

                    req.data['last_undoable_transaction'] = txuuid

        ### error case

        except NotFound as ex:

            result = self.notfound_content(req)