~azzar1/unity/add-show-desktop-key

# IVLE - Informatics Virtual Learning Environment

# Copyright (C) 2007-2008 The University of Melbourne

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program 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 General Public License for more details.

#

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

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Module: Subject Pulldown

# Author: Matt Giuca

# Date:   7/7/2008

# Pluggable subject pulldown module.

# Grabs a student's subject list from a source specified in conf.py.

# Each module should have a get_subjects(login) function, which takes login

# and returns a list of (subject, semester) pairs (both strings), or None

# if the user can't be found. May also raise a SubjectError which is fatal.

import os

import sys

import datetime

from subjecterror import SubjectError

from ivle.database import Subject, Offering, Semester

def get_subjects(config, login):

    """

    Looks up the student in whatever modules are available, using login.

    If successful, returns a list of (subject, semester) pairs (both strings).

    Raises a SubjectError if unsuccessful.

    """

    for modname, m in get_pulldown_modules(config):

        result = m(login)

        if result is not None:

            return result

    return []

def enrol_user(config, store, user, year=None):

    """

    Looks up the student in whatever modules are available.

    The pulldown does not tell us what year to enrol the student for, so the

    year may be specified (as a string). If unspecified, will enrol in the

    current year according to the system clock.

    If successful, enrols the student (in the database) in all subjects in the

    system. Subjects which the pulldown tells us the student is in, but which

    are not in the system are ignored.

    Does not unenrol the student from any subjects.

    Does not complain if the student is already enrolled in any subjects.

    Raises a SubjectError if the pulldown module says so.

    Returns the number of subjects the user was enrolled in (not including

    subjects outside the system, or subjects already enrolled).

    """

    if year is None:

        year = unicode(datetime.datetime.now().year)

    count = 0

    for subject, semester in get_subjects(config, user.login):

        offering = store.find(Offering,

                              Subject.code == subject,

                              Offering.subject_id == Subject.id,

                              Semester.year == year,

                              Semester.semester == semester,

                              Offering.semester_id == Semester.id).one()

        # We can't find a matching offering, so we don't care about it.

        if not offering:

            continue

        offering.enrol(user)

        count += 1

    return count

def get_pulldown_modules(config):

    """Get the subject pulldown modules defined in the configuration.

    Returns a list of (name, function object)s. The list consists of

    the "get_subject" functions of all the plugin subject pulldown modules.

    """

    oldpath = sys.path

    # Allow imports to get files from this directory.

    # Get the directory that this module (authenticate) is in

    plugpath = os.path.split(sys.modules[__name__].__file__)[0]

    # Add it to sys.path

    sys.path.append(plugpath)

    subj_modules = []

    for modname in config['auth']['subject_pulldown_modules']:

        try:

            mod = __import__(modname)

        except ImportError:

            raise SubjectError("Internal error: "

                "Can't import subject pulldown module %s"

                % repr(modname))

        except ValueError:

            # If auth_modules is "", we may get an empty string - ignore

            continue

        try:

            subjfunc = mod.get_subjects

        except AttributeError:

            raise SubjectError("Internal error: Subject pulldown module %r has no "

                "'get_subjects' function" % modname)

        subj_modules.append((modname, subjfunc))

    # Restore the old path, without this directory in it.

    sys.path = oldpath

    return subj_modules