util.py

# Copyright 2011-2012 GRNET S.A. All rights reserved.
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import logging
import datetime
import time

from urllib import quote

from datetime import tzinfo, timedelta
from django.http import HttpResponse, HttpResponseBadRequest, urlencode
from django.template import RequestContext
from django.utils.translation import ugettext as _
from django.contrib.auth import authenticate
from django.core.urlresolvers import reverse
from django.core.exceptions import ValidationError, ObjectDoesNotExist
from django.db.models.fields import Field
from django.utils.translation import ugettext as _

from astakos.im.models import AstakosUser, Invitation
from astakos.im.settings import COOKIE_NAME, \
    COOKIE_DOMAIN, COOKIE_SECURE, FORCE_PROFILE_UPDATE, LOGGING_LEVEL
from astakos.im.functions import login

import astakos.im.messages as astakos_messages

logger = logging.getLogger(__name__)


class UTC(tzinfo):
    def utcoffset(self, dt):
        return timedelta(0)

    def tzname(self, dt):
        return 'UTC'

    def dst(self, dt):
        return timedelta(0)


def isoformat(d):
    """Return an ISO8601 date string that includes a timezone."""

    return d.replace(tzinfo=UTC()).isoformat()


def epoch(datetime):
    return int(time.mktime(datetime.timetuple()) * 1000)


def get_context(request, extra_context=None, **kwargs):
    extra_context = extra_context or {}
    extra_context.update(kwargs)
    return RequestContext(request, extra_context)


def get_invitation(request):
    """
    Returns the invitation identified by the ``code``.

    Raises ValueError if the invitation is consumed or there is another account
    associated with this email.
    """
    code = request.GET.get('code')
    if request.method == 'POST':
        code = request.POST.get('code')
    if not code:
        return
    invitation = Invitation.objects.get(code=code)
    if invitation.is_consumed:
        raise ValueError(_(astakos_messages.INVITATION_CONSUMED_ERR))
    if reserved_email(invitation.username):
        email = invitation.username
        raise ValueError(_(astakos_messages.EMAIL_RESRVED) % locals()))
    return invitation


def prepare_response(request, user, next='', renew=False):
    """Return the unique username and the token
       as 'X-Auth-User' and 'X-Auth-Token' headers,
       or redirect to the URL provided in 'next'
       with the 'user' and 'token' as parameters.

       Reissue the token even if it has not yet
       expired, if the 'renew' parameter is present
       or user has not a valid token.
    """
    renew = renew or (not user.auth_token)
    renew = renew or (user.auth_token_expires < datetime.datetime.now())
    if renew:
        user.renew_token()
        try:
            user.save()
        except ValidationError, e:
            return HttpResponseBadRequest(e)

    if FORCE_PROFILE_UPDATE and not user.is_verified and not user.is_superuser:
        params = ''
        if next:
            params = '?' + urlencode({'next': next})
        next = reverse('edit_profile') + params

    response = HttpResponse()

    # authenticate before login
    user = authenticate(email=user.email, auth_token=user.auth_token)
    login(request, user)
    set_cookie(response, user)
    request.session.set_expiry(user.auth_token_expires)

    if not next:
        next = reverse('index')

    response['Location'] = next
    response.status_code = 302
    return response


def set_cookie(response, user):
    expire_fmt = user.auth_token_expires.strftime('%a, %d-%b-%Y %H:%M:%S %Z')
    cookie_value = quote(user.email + '|' + user.auth_token)
    response.set_cookie(COOKIE_NAME, value=cookie_value,
                        expires=expire_fmt, path='/',
                        domain=COOKIE_DOMAIN, secure=COOKIE_SECURE)
    msg = 'Cookie [expiring %s] set for %s' % (
        user.auth_token_expires,
        user.email
    )
    logger.log(LOGGING_LEVEL, msg)


class lazy_string(object):
    def __init__(self, function, *args, **kwargs):
        self.function = function
        self.args = args
        self.kwargs = kwargs

    def __str__(self):
        if not hasattr(self, 'str'):
            self.str = self.function(*self.args, **self.kwargs)
        return self.str


def reverse_lazy(*args, **kwargs):
    return lazy_string(reverse, *args, **kwargs)


def reserved_email(email):
    return AstakosUser.objects.filter(email__iexact=email).count() != 0


def get_query(request):
    try:
        return request.__getattribute__(request.method)
    except AttributeError:
        return {}


def model_to_dict(obj, exclude=['AutoField', 'ForeignKey', 'OneToOneField'],
                  include_empty=True):
    '''
        serialize model object to dict with related objects

        author: Vadym Zakovinko <vp@zakovinko.com>
        date: January 31, 2011
        http://djangosnippets.org/snippets/2342/
    '''
    tree = {}
    for field_name in obj._meta.get_all_field_names():
        try:
            field = getattr(obj, field_name)
        except (ObjectDoesNotExist, AttributeError):
            continue

        if field.__class__.__name__ in ['RelatedManager', 'ManyRelatedManager']:
            if field.model.__name__ in exclude:
                continue

            if field.__class__.__name__ == 'ManyRelatedManager':
                exclude.append(obj.__class__.__name__)
            subtree = []
            for related_obj in getattr(obj, field_name).all():
                value = model_to_dict(related_obj, exclude=exclude)
                if value or include_empty:
                    subtree.append(value)
            if subtree or include_empty:
                tree[field_name] = subtree
            continue

        field = obj._meta.get_field_by_name(field_name)[0]
        if field.__class__.__name__ in exclude:
            continue

        if field.__class__.__name__ == 'RelatedObject':
            exclude.append(field.model.__name__)
            tree[field_name] = model_to_dict(getattr(obj, field_name),
                                             exclude=exclude)
            continue

        value = getattr(obj, field_name)
        if field.__class__.__name__ == 'ForeignKey':
            value = unicode(value) if value is not None else value
        if value or include_empty:
            tree[field_name] = value

    return tree