"""twisted server for CubicWeb web instances

:organization: Logilab

:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.

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

:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses

"""

__docformat__ = "restructuredtext en"

import sys

import os

import select

import errno

from time import mktime

from datetime import date, timedelta

from urlparse import urlsplit, urlunsplit

from cgi import FieldStorage, parse_header

from twisted.internet import reactor, task, threads

from twisted.internet.defer import maybeDeferred

from twisted.web import http, server

from twisted.web import static, resource

from twisted.web.server import NOT_DONE_YET

from logilab.common.decorators import monkeypatch

from cubicweb import ConfigurationError, CW_EVENT_MANAGER

from cubicweb.web import (AuthenticationError, NotFound, Redirect,

                          RemoteCallFailed, DirectResponse, StatusResponse,

                          ExplicitLogin)

from cubicweb.web.application import CubicWebPublisher

from cubicweb.etwist.request import CubicWebTwistedRequestAdapter

from cubicweb.etwist.http import HTTPResponse

def daemonize():

    # XXX unix specific

    # XXX factorize w/ code in cw.server.server and cw.server.serverctl

    # (start-repository command)

    # See http://www.erlenstar.demon.co.uk/unix/faq_toc.html#TOC16

    if os.fork():   # launch child and...

        return 1

    os.setsid()

    if os.fork():   # launch child again.

        return 1

    # move to the root to avoit mount pb

    os.chdir('/')

    # set paranoid umask

    os.umask(077)

    null = os.open('/dev/null', os.O_RDWR)

    for i in range(3):

        try:

            os.dup2(null, i)

        except OSError, e:

            if e.errno != errno.EBADF:

                raise

    os.close(null)

    return None

def start_task(interval, func):

    lc = task.LoopingCall(func)

    # wait until interval has expired to actually start the task, else we have

    # to wait all task to be finished for the server to be actually started

    lc.start(interval, now=False)

def host_prefixed_baseurl(baseurl, host):

    scheme, netloc, url, query, fragment = urlsplit(baseurl)

    netloc_domain = '.' + '.'.join(netloc.split('.')[-2:])

    if host.endswith(netloc_domain):

        netloc = host

    baseurl = urlunsplit((scheme, netloc, url, query, fragment))

    return baseurl

class ForbiddenDirectoryLister(resource.Resource):

    def render(self, request):

        return HTTPResponse(twisted_request=request,

                            code=http.FORBIDDEN,

                            stream='Access forbidden')

class File(static.File):

    """Prevent from listing directories"""

    def directoryListing(self):

        return ForbiddenDirectoryLister()

class LongTimeExpiringFile(File):

    """overrides static.File and sets a far future ``Expires`` date

    on the resouce.

    versions handling is done by serving static files by different

    URLs for each version. For instance::

      http://localhost:8080/data-2.48.2/cubicweb.css

      http://localhost:8080/data-2.49.0/cubicweb.css

      etc.

    """

    def render(self, request):

class CubicWebRootResource(resource.Resource):

    def __init__(self, config, debug=None):

        self.debugmode = debug

        self.config = config

        # instantiate publisher here and not in init_publisher to get some

        # checks done before daemonization (eg versions consistency)

        self.appli = CubicWebPublisher(config, debug=self.debugmode)

        self.base_url = config['base-url']

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

        self.children = {}

    def init_publisher(self):

        config = self.config

        # when we have an in-memory repository, clean unused sessions every XX

        # seconds and properly shutdown the server

        if config.repo_method == 'inmemory':

            reactor.addSystemEventTrigger('before', 'shutdown',

                                          self.shutdown_event)

            if config.pyro_enabled():

                # if pyro is enabled, we have to register to the pyro name

                # server, create a pyro daemon, and create a task to handle pyro

                # requests

                self.pyro_daemon = self.appli.repo.pyro_register()

                self.pyro_listen_timeout = 0.02

                self.appli.repo.looping_task(1, self.pyro_loop_event)

            self.appli.repo.start_looping_tasks()

        self.set_url_rewriter()

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

    def start_service(self):

        config = self.config

        interval = min(config['cleanup-session-time'] or 120,

                       config['cleanup-anonymous-session-time'] or 720) / 2.

        start_task(interval, self.appli.session_handler.clean_sessions)

    def set_url_rewriter(self):

        self.url_rewriter = self.appli.vreg['components'].select_or_none('urlrewriter')

    def shutdown_event(self):

        """callback fired when the server is shutting down to properly

        clean opened sessions

        """

        self.appli.repo.shutdown()

    def pyro_loop_event(self):

        """listen for pyro events"""

        try:

            self.pyro_daemon.handleRequests(self.pyro_listen_timeout)

        except select.error:

            return

    def getChild(self, path, request):

        """Indicate which resource to use to process down the URL's path"""

                datadir = self.config.static_directory

            else:

                datadir = self.config.locate_resource(path)

                if datadir is None:

                    return self

        # Otherwise we use this single resource

        return self

    def render(self, request):

        """Render a page from the root resource"""

        # reload modified files in debug mode

        if self.debugmode:

            self.appli.vreg.register_objects(self.config.vregistry_path())

        if self.config['profile']: # default profiler don't trace threads

            return self.render_request(request)

        else:

            deferred = threads.deferToThread(self.render_request, request)

            return NOT_DONE_YET

    def render_request(self, request):

        origpath = request.path

        host = request.host

        # dual http/https access handling: expect a rewrite rule to prepend

        # 'https' to the path to detect https access

        if origpath.split('/', 2)[1] == 'https':

            origpath = origpath[6:]

            request.uri = request.uri[6:]

            https = True

            baseurl = self.https_url or self.base_url

        else:

            https = False

            baseurl = self.base_url

        if self.config['use-request-subdomain']:

            baseurl = host_prefixed_baseurl(baseurl, host)

            self.warning('used baseurl is %s for this request', baseurl)

        req = CubicWebTwistedRequestAdapter(request, self.appli.vreg, https, baseurl)

        if req.authmode == 'http':

            # activate realm-based auth

            realm = self.config['realm']

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

        try:

            self.appli.connect(req)

        except AuthenticationError:

            return self.request_auth(request=req)

        except Redirect, ex:

            return self.redirect(request=req, location=ex.location)

        if https and req.cnx.anonymous_connection:

            # don't allow anonymous on https connection

            return self.request_auth(request=req)

        if self.url_rewriter is not None:

            # XXX should occur before authentication?

            try:

                path = self.url_rewriter.rewrite(host, origpath, req)

            except Redirect, ex:

                return self.redirect(req, ex.location)

            request.uri.replace(origpath, path, 1)

        else:

            path = origpath

        if not path or path == "/":

            path = 'view'

        try:

            result = self.appli.publish(path, req)

        except DirectResponse, ex:

            return ex.response

        except StatusResponse, ex:

            return HTTPResponse(stream=ex.content, code=ex.status,

                                twisted_request=req._twreq,

                                headers=req.headers_out)

        except RemoteCallFailed, ex:

            req.set_header('content-type', 'application/json')

            return HTTPResponse(twisted_request=req._twreq, code=http.INTERNAL_SERVER_ERROR,

                                stream=ex.dumps(), headers=req.headers_out)

        except NotFound:

            result = self.appli.notfound_content(req)

            return HTTPResponse(twisted_request=req._twreq, code=http.NOT_FOUND,

                                stream=result, headers=req.headers_out)

        except ExplicitLogin:  # must be before AuthenticationError

            return self.request_auth(request=req)

        except AuthenticationError, ex:

            if self.config['auth-mode'] == 'cookie' and getattr(ex, 'url', None):

                return self.redirect(request=req, location=ex.url)

            # in http we have to request auth to flush current http auth

            # information

            return self.request_auth(request=req, loggedout=True)

        except Redirect, ex:

            return self.redirect(request=req, location=ex.location)

        # request may be referenced by "onetime callback", so clear its entity

        # cache to avoid memory usage

        req.drop_entity_cache()

        return HTTPResponse(twisted_request=req._twreq, code=http.OK,

                            stream=result, headers=req.headers_out)

    def redirect(self, request, location):

        self.debug('redirecting to %s', str(location))

        request.headers_out.setHeader('location', str(location))

        # 303 See other

        return HTTPResponse(twisted_request=request._twreq, code=303,

                            headers=request.headers_out)

    def request_auth(self, request, loggedout=False):

        if self.https_url and request.base_url() != self.https_url:

            return self.redirect(request, self.https_url + 'login')

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

            code = http.UNAUTHORIZED

        else:

            code = http.FORBIDDEN

        if loggedout:

            if request.https:

                request._base_url =  self.base_url

                request.https = False

            content = self.appli.loggedout_content(request)

        else:

            content = self.appli.need_login_content(request)

        return HTTPResponse(twisted_request=request._twreq,

                            stream=content, code=code,

                            headers=request.headers_out)

#TODO

# # XXX max upload size in the configuration

@monkeypatch(http.Request)

def requestReceived(self, command, path, version):

    """Called by channel when all data has been received.

    This method is not intended for users.

    """

    self.content.seek(0,0)

    self.args = {}

    self.files = {}

    self.stack = []

    self.method, self.uri = command, path

    self.clientproto = version

    x = self.uri.split('?', 1)

    if len(x) == 1:

        self.path = self.uri

    else:

        self.path, argstring = x

        self.args = http.parse_qs(argstring, 1)

    # cache the client and server information, we'll need this later to be

    # serialized and sent with the request so CGIs will work remotely

    self.client = self.channel.transport.getPeer()

    self.host = self.channel.transport.getHost()

    # Argument processing

    ctype = self.getHeader('content-type')

    if self.method == "POST" and ctype:

        key, pdict = parse_header(ctype)

        if key == 'application/x-www-form-urlencoded':

            self.args.update(http.parse_qs(self.content.read(), 1))

        elif key == 'multipart/form-data':

            self.content.seek(0,0)

            form = FieldStorage(self.content, self.received_headers,

                                environ={'REQUEST_METHOD': 'POST'},

                                keep_blank_values=1,

                                strict_parsing=1)

            for key in form:

                value = form[key]

                if isinstance(value, list):

                    self.args[key] = [v.value for v in value]

                elif value.filename:

                    if value.done != -1: # -1 is transfer has been interrupted

                        self.files[key] = (value.filename, value.file)

                    else:

                        self.files[key] = (None, None)

                else:

                    self.args[key] = value.value

    self.process()

from logging import getLogger

from cubicweb import set_log_methods

LOGGER = getLogger('cubicweb.twisted')

set_log_methods(CubicWebRootResource, LOGGER)

def run(config, debug):

    # create the site

    root_resource = CubicWebRootResource(config, debug)

    website = server.Site(root_resource)

    # serve it via standard HTTP on port set in the configuration

    port = config['port'] or 8080

    reactor.listenTCP(port, website)

    logger = getLogger('cubicweb.twisted')

    if not debug:

        if sys.platform == 'win32':

            raise ConfigurationError("Under windows, you must use the service management "

                                     "commands (e.g : 'net start my_instance)'")

        print 'instance starting in the background'