flow.py

# -*- coding: utf-8 -*-

from __future__ import division

__copyright__ = "Copyright (C) 2014 Andreas Kloeckner"

__license__ = """
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

from django.shortcuts import (  # noqa
        render, get_object_or_404, redirect)
from django.contrib import messages
from django.core.exceptions import (
        PermissionDenied, SuspiciousOperation,
        ObjectDoesNotExist)
from django.db import transaction
from django.utils.safestring import mark_safe
from django import forms
from django import http

from relate.utils import StyledForm, local_now, as_local_time
from crispy_forms.layout import Submit

from course.constants import (
        flow_permission,
        participation_role,
        flow_session_expiration_mode,
        FLOW_SESSION_EXPIRATION_MODE_CHOICES,
        is_expiration_mode_allowed,
        flow_rule_kind)
from course.models import (
        FlowSession, FlowPageData, FlowPageVisit,
        FlowPageVisitGrade,
        get_feedback_for_grade,
        GradeChange, update_bulk_feedback)

from course.utils import (
        FlowContext, FlowPageContext,
        instantiate_flow_page_with_ctx,
        course_view, render_course_page,
        get_session_start_rule,
        get_session_access_rule,
        get_session_grading_rule,
        FlowSessionGradingRule)
from course.views import get_now_or_fake_time


# {{{ grade page visit

def grade_page_visit(visit, visit_grade_model=FlowPageVisitGrade,
        grade_data=None, graded_at_git_commit_sha=None):
    if not visit.is_submitted_answer:
        raise RuntimeError("cannot grade ungraded answer")

    flow_session = visit.flow_session
    course = flow_session.course
    page_data = visit.page_data

    most_recent_grade = visit.get_most_recent_grade()
    if most_recent_grade is not None and grade_data is None:
        grade_data = most_recent_grade.grade_data

    from course.content import (
            get_course_repo,
            get_course_commit_sha,
            get_flow_desc,
            get_flow_page_desc,
            instantiate_flow_page)

    repo = get_course_repo(course)

    course_commit_sha = get_course_commit_sha(
            course, flow_session.participation)

    flow_desc = get_flow_desc(repo, course,
            flow_session.flow_id, course_commit_sha)

    page_desc = get_flow_page_desc(
            flow_session.flow_id,
            flow_desc,
            page_data.group_id, page_data.page_id)

    page = instantiate_flow_page(
            location="flow '%s', group, '%s', page '%s'"
            % (flow_session.flow_id, page_data.group_id, page_data.page_id),
            repo=repo, page_desc=page_desc,
            commit_sha=course_commit_sha)

    assert page.expects_answer()
    if not page.is_answer_gradable():
        return

    from course.page import PageContext
    grading_page_context = PageContext(
            course=course,
            repo=repo,
            commit_sha=course_commit_sha,
            flow_session=flow_session)

    answer_feedback = page.grade(
            grading_page_context, visit.page_data.data,
            visit.answer, grade_data=grade_data)

    grade = visit_grade_model()
    grade.visit = visit
    grade.grade_data = grade_data
    grade.max_points = page.max_points(visit.page_data)
    grade.graded_at_git_commit_sha = graded_at_git_commit_sha

    bulk_feedback_json = None
    if answer_feedback is not None:
        grade.correctness = answer_feedback.correctness
        grade.feedback, bulk_feedback_json = answer_feedback.as_json()

    grade.save()

    update_bulk_feedback(page_data, grade, bulk_feedback_json)

# }}}


# {{{ start flow

def start_flow(repo, course, participation, flow_id, flow_desc,
        access_rules_tag, now_datetime):
    from course.content import get_course_commit_sha
    course_commit_sha = get_course_commit_sha(course, participation)

    session = FlowSession(
        course=course,
        participation=participation,
        active_git_commit_sha=course_commit_sha.decode(),
        flow_id=flow_id,
        in_progress=True,
        expiration_mode=flow_session_expiration_mode.end,
        access_rules_tag=access_rules_tag)

    session.save()

    # Create flow grading opportunity. This makes the flow
    # show up in the grade book.

    from course.utils import get_flow_rules
    from course.models import get_flow_grading_opportunity
    for grading_rule in get_flow_rules(
            flow_desc, flow_rule_kind.grading, participation,
            flow_id, now_datetime, consider_exceptions=False):
        identifier = getattr(grading_rule, "grade_identifier", None)
        if identifier is not None:
            get_flow_grading_opportunity(
                    course, flow_id, flow_desc,
                    FlowSessionGradingRule(
                        grade_identifier=identifier,
                        grade_aggregation_strategy=getattr(
                            grading_rule, "grade_aggregation_strategy"),
                        ))

    # will implicitly modify and save the session if there are changes
    from course.content import adjust_flow_session_page_data
    adjust_flow_session_page_data(repo, session,
            course.identifier, flow_desc, course_commit_sha)

    return session

# }}}


# {{{ finish flow

def get_flow_session_graded_answers_qset(flow_session):
    from django.db.models import Q
    qset = (FlowPageVisit.objects
            .filter(flow_session=flow_session)
            .filter(Q(answer__isnull=False) | Q(is_synthetic=True)))

    if not flow_session.in_progress:
        # Ungraded answers *can* show up in non-in-progress flows as a result
        # of a race between a 'save' and the 'end session'. If this happens,
        # we'll go ahead and ignore those.
        qset = qset.filter(is_submitted_answer=True)

    return qset