Synnefo

# Copyright 2011 GRNET S.A. All rights reserved.

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from django.conf import settings

from django.http import HttpResponse, HttpResponseRedirect

from synnefo.db.models import SynnefoUser

from synnefo.aai.shibboleth import Tokens, register_shibboleth_user

import time

class SynnefoAuthMiddleware(object):

    auth_token = "X-Auth-Token"

    auth_user  = "X-Auth-User"

    auth_key   = "X-Auth-Key"

    def process_request(self, request):

        if request.path.startswith('/api/') :

            return

        if request.path.startswith('/invitations/login') :

            return

        # Special case for testing purposes, delivers the cookie for the

        # test user on first access

        if settings.BYPASS_AUTHENTICATION and \

           request.GET.get('test') is not None:

            u = SynnefoUser.objects.get(

                auth_token='46e427d657b20defe352804f0eb6f8a2')

            return self._redirect_shib_auth_user(user = u)

        token = None

        #Try to find token in a cookie

        try:

            token = request.COOKIES['X-Auth-Token']

        except Exception:

            pass

        #Try to find token in request header

        if not token:

            token = request.META.get('HTTP_X_AUTH_TOKEN', None)

        if token:

            user = None

            #Retrieve user from DB or other caching mechanism

            try:

                user = SynnefoUser.objects.get(auth_token=token)

            except SynnefoUser.DoesNotExist:

                return HttpResponseRedirect(settings.APP_INSTALL_URL + settings.LOGIN_PATH)

            #Check user's auth token

            if (time.time() -

                time.mktime(user.auth_token_expires.timetuple())) > 0:

                #The user's token has expired, re-login

                return HttpResponseRedirect(settings.APP_INSTALL_URL + settings.LOGIN_PATH)

            request.user = user

            return

        #A user authenticated by Shibboleth, must include a uniq id

        if Tokens.SIB_EPPN in request.META and Tokens.SIB_SESSION_ID in request.META:

            user = None

            try:

                user = SynnefoUser.objects.get(

                    uniq = request.META[Tokens.SIB_EPPN])

            except SynnefoUser.DoesNotExist:

                pass

            #No user with this id could be found in the database

            if user is None:

                #Attempt to register the incoming user

                if register_shibboleth_user(request.META):

                    user = SynnefoUser.objects.get(

                        uniq = request.META[Tokens.SIB_EPPN])

                    return self._redirect_shib_auth_user(user)

                else:

                    return HttpResponseRedirect(settings.APP_INSTALL_URL + settings.LOGIN_PATH)

            #User and authentication token valid, user allowed to proceed

            return self._redirect_shib_auth_user(user)

        if settings.TEST:

            if 'TEST-AAI' in request.META:

                return HttpResponseRedirect(settings.APP_INSTALL_URL + settings.LOGIN_PATH)

        else:

            #Avoid redirect loops

            if request.path.endswith(settings.LOGIN_PATH): 

                return

            else :

                #No authentication info found in headers, redirect to Shibboleth

                return HttpResponseRedirect(settings.APP_INSTALL_URL + settings.LOGIN_PATH)

    def process_response(self, request, response):

        #Tell proxies and other interested parties that the

        #request varies based on the auth token, to avoid

        #caching of results

        response['Vary'] = self.auth_token

        return response

    def _redirect_shib_auth_user(self, user):

        expire_fmt = user.auth_token_expires.strftime('%a, %d-%b-%Y %H:%M:%S %Z')

        response = HttpResponse()

        response.set_cookie('X-Auth-Token', value=user.auth_token, expires = expire_fmt, path='/')

        response[self.auth_token] = user.auth_token

        response['Location'] = settings.APP_INSTALL_URL

        response.status_code = 302

        return response