예제 #1
0
def view_reopen_session(pctx, flow_session_id, opportunity_id):
    if pctx.role not in [
            participation_role.instructor,
            participation_role.teaching_assistant
    ]:
        raise PermissionDenied()

    request = pctx.request

    session = get_object_or_404(FlowSession, id=int(flow_session_id))

    from course.content import get_flow_desc
    try:
        flow_desc = get_flow_desc(pctx.repo, pctx.course, session.flow_id,
                                  pctx.course_commit_sha)
    except ObjectDoesNotExist:
        raise http.Http404()

    if request.method == "POST":
        form = ReopenSessionForm(flow_desc, session.access_rules_tag,
                                 request.POST, request.FILES)

        if form.is_valid():
            new_access_rules_tag = form.cleaned_data["set_access_rules_tag"]
            if new_access_rules_tag == NONE_SESSION_TAG:
                new_access_rules_tag = None

            session.access_rules_tag = new_access_rules_tag

            from relate.utils import (local_now, as_local_time,
                                      format_datetime_local)
            session.append_comment(
                ugettext("Session reopened at %(now)s by %(user)s, "
                         "previous completion time was '%(completion_time)s': "
                         "%(comment)s.") % {
                             "now":
                             format_datetime_local(local_now()),
                             "user":
                             pctx.request.user,
                             "completion_time":
                             format_datetime_local(
                                 as_local_time(session.completion_time)),
                             "comment":
                             form.cleaned_data["comment"]
                         })
            session.save()

            from course.flow import reopen_session
            reopen_session(session, suppress_log=True)

            return redirect("relate-view_single_grade", pctx.course.identifier,
                            session.participation.id, opportunity_id)

    else:
        form = ReopenSessionForm(flow_desc, session.access_rules_tag)

    return render(request, "generic-form.html", {
        "form": form,
        "form_description": _("Reopen session")
    })
예제 #2
0
파일: grades.py 프로젝트: akiyoko/relate
def view_reopen_session(pctx, flow_session_id, opportunity_id):
    if pctx.role not in [
            participation_role.instructor,
            participation_role.teaching_assistant]:
        raise PermissionDenied()

    request = pctx.request

    session = get_object_or_404(FlowSession, id=int(flow_session_id))

    from course.content import get_flow_desc
    try:
        flow_desc = get_flow_desc(pctx.repo, pctx.course, session.flow_id,
                pctx.course_commit_sha)
    except ObjectDoesNotExist:
        raise http.Http404()

    if request.method == "POST":
        form = ReopenSessionForm(flow_desc, session.access_rules_tag,
            request.POST, request.FILES)

        if form.is_valid():
            new_access_rules_tag = form.cleaned_data["set_access_rules_tag"]
            if new_access_rules_tag == NONE_SESSION_TAG:
                new_access_rules_tag = None

            session.access_rules_tag = new_access_rules_tag

            from relate.utils import (
                    local_now, as_local_time,
                    format_datetime_local)
            session.append_comment(
                    ugettext("Session reopened at %(now)s by %(user)s, "
                        "previous completion time was '%(completion_time)s': "
                        "%(comment)s.") % {
                            "now": format_datetime_local(local_now()),
                            "user": pctx.request.user,
                            "completion_time": format_datetime_local(
                                as_local_time(session.completion_time)),
                            "comment": form.cleaned_data["comment"]
                            })
            session.save()

            from course.flow import reopen_session
            reopen_session(session, suppress_log=True)

            return redirect("relate-view_single_grade",
                    pctx.course.identifier,
                    session.participation.id,
                    opportunity_id)

    else:
        form = ReopenSessionForm(flow_desc, session.access_rules_tag)

    return render(request, "generic-form.html", {
        "form": form,
        "form_description": _("Reopen session")
        })
예제 #3
0
파일: flow.py 프로젝트: gboone/relate
def reopen_session(session, force=False, suppress_log=False):
    if session.in_progress:
        raise RuntimeError(_("Can't reopen a session that's already in progress"))
    if session.participation is None:
        raise RuntimeError(_("Can't reopen anonymous sessions"))

    session.in_progress = True
    session.points = None
    session.max_points = None

    if not suppress_log:
        session.append_comment(
            _("Session reopened at %(now)s, previous completion time " "was '%(complete_time)s'.")
            % {
                "now": format_datetime_local(local_now()),
                "complete_time": format_datetime_local(as_local_time(session.completion_time)),
            }
        )

    session.completion_time = None
    session.save()
예제 #4
0
    def grade(self, page_context, page_data, answer_data, grade_data):
        if answer_data is None:
            return AnswerFeedback(correctness=0,
                                  feedback=_("No answer provided."))

        user_code = answer_data["answer"]

        # {{{ request run

        run_req = {"compile_only": False, "user_code": user_code}

        def transfer_attr(name):
            if hasattr(self.page_desc, name):
                run_req[name] = getattr(self.page_desc, name)

        transfer_attr("setup_code")
        transfer_attr("names_for_user")
        transfer_attr("names_from_user")

        run_req["test_code"] = self.get_test_code()

        if hasattr(self.page_desc, "data_files"):
            run_req["data_files"] = {}

            from course.content import get_repo_blob

            for data_file in self.page_desc.data_files:
                from base64 import b64encode
                run_req["data_files"][data_file] = \
                        b64encode(
                                get_repo_blob(
                                    page_context.repo, data_file,
                                    page_context.commit_sha).data).decode()

        try:
            response_dict = request_run_with_retries(
                run_req,
                run_timeout=self.page_desc.timeout,
                image=self.container_image)
        except Exception:
            from traceback import format_exc
            response_dict = {
                "result": "uncaught_error",
                "message": "Error connecting to container",
                "traceback": "".join(format_exc()),
            }

        # }}}

        feedback_bits = []

        correctness = None

        if "points" in response_dict:
            correctness = response_dict["points"]
            try:
                feedback_bits.append("<p><b>%s</b></p>" %
                                     _(get_auto_feedback(correctness)))
            except Exception as e:
                correctness = None
                response_dict["result"] = "setup_error"
                response_dict["message"] = ("%s: %s" %
                                            (type(e).__name__, str(e)))

        # {{{ send email if the grading code broke

        if response_dict["result"] in [
                "uncaught_error", "setup_compile_error", "setup_error",
                "test_compile_error", "test_error"
        ]:
            error_msg_parts = ["RESULT: %s" % response_dict["result"]]
            for key, val in sorted(response_dict.items()):
                if (key not in ["result", "figures"] and val
                        and isinstance(val, str)):
                    error_msg_parts.append(
                        "-------------------------------------")
                    error_msg_parts.append(key)
                    error_msg_parts.append(
                        "-------------------------------------")
                    error_msg_parts.append(val)
            error_msg_parts.append("-------------------------------------")
            error_msg_parts.append("user code")
            error_msg_parts.append("-------------------------------------")
            error_msg_parts.append(user_code)
            error_msg_parts.append("-------------------------------------")

            error_msg = "\n".join(error_msg_parts)

            from relate.utils import local_now, format_datetime_local
            from course.utils import LanguageOverride
            with LanguageOverride(page_context.course):
                from relate.utils import render_email_template
                message = render_email_template(
                    "course/broken-code-question-email.txt", {
                        "site": getattr(settings, "RELATE_BASE_URL"),
                        "page_id": self.page_desc.id,
                        "course": page_context.course,
                        "error_message": error_msg,
                        "review_uri": page_context.page_uri,
                        "time": format_datetime_local(local_now())
                    })

                if (not page_context.in_sandbox
                        and not is_nuisance_failure(response_dict)):
                    try:
                        from django.core.mail import EmailMessage
                        msg = EmailMessage(
                            "".join([
                                "[%s:%s] ",
                                _("code question execution failed")
                            ]) % (page_context.course.identifier,
                                  page_context.flow_session.flow_id
                                  if page_context.flow_session is not None else
                                  _("<unknown flow>")), message,
                            settings.ROBOT_EMAIL_FROM,
                            [page_context.course.notify_email])

                        from relate.utils import get_outbound_mail_connection
                        msg.connection = get_outbound_mail_connection("robot")
                        msg.send()

                    except Exception:
                        from traceback import format_exc
                        feedback_bits.append(
                            str(
                                string_concat(
                                    "<p>",
                                    _("Both the grading code and the attempt to "
                                      "notify course staff about the issue failed. "
                                      "Please contact the course or site staff and "
                                      "inform them of this issue, mentioning this "
                                      "entire error message:"), "</p>", "<p>",
                                    _("Sending an email to the course staff about the "
                                      "following failure failed with "
                                      "the following error message:"), "<pre>",
                                    "".join(format_exc()), "</pre>",
                                    _("The original failure message follows:"),
                                    "</p>")))

        # }}}

        if hasattr(self.page_desc, "correct_code"):

            def normalize_code(s):
                return (s.replace(" ", "").replace("\r", "").replace(
                    "\n", "").replace("\t", ""))

            if (normalize_code(user_code) == normalize_code(
                    self.page_desc.correct_code)):
                feedback_bits.append(
                    "<p><b>%s</b></p>" %
                    _("It looks like you submitted code that is identical to "
                      "the reference solution. This is not allowed."))

        from relate.utils import dict_to_struct
        response = dict_to_struct(response_dict)

        bulk_feedback_bits = []

        if response.result == "success":
            pass
        elif response.result in [
                "uncaught_error", "setup_compile_error", "setup_error",
                "test_compile_error", "test_error"
        ]:
            feedback_bits.append("".join([
                "<p>",
                _("The grading code failed. Sorry about that. "
                  "The staff has been informed, and if this problem is "
                  "due to an issue with the grading code, "
                  "it will be fixed as soon as possible. "
                  "In the meantime, you'll see a traceback "
                  "below that may help you figure out what went wrong."),
                "</p>"
            ]))
        elif response.result == "timeout":
            feedback_bits.append("".join([
                "<p>",
                _("Your code took too long to execute. The problem "
                  "specifies that your code may take at most %s seconds "
                  "to run. "
                  "It took longer than that and was aborted."), "</p>"
            ]) % self.page_desc.timeout)

            correctness = 0
        elif response.result == "user_compile_error":
            feedback_bits.append("".join([
                "<p>",
                _("Your code failed to compile. An error message is "
                  "below."), "</p>"
            ]))

            correctness = 0
        elif response.result == "user_error":
            feedback_bits.append("".join([
                "<p>",
                _("Your code failed with an exception. "
                  "A traceback is below."), "</p>"
            ]))

            correctness = 0
        else:
            raise RuntimeError("invalid run result: %s" % response.result)

        if hasattr(response, "feedback") and response.feedback:

            def sanitize(s):
                import bleach
                return bleach.clean(s, tags=["p", "pre"])

            feedback_bits.append("".join([
                "<p>",
                _("Here is some feedback on your code"), ":"
                "<ul>%s</ul></p>"
            ]) % "".join("<li>%s</li>" % sanitize(fb_item)
                         for fb_item in response.feedback))
        if hasattr(response, "traceback") and response.traceback:
            feedback_bits.append("".join([
                "<p>",
                _("This is the exception traceback"), ":"
                "<pre>%s</pre></p>"
            ]) % escape(response.traceback))
        if hasattr(response,
                   "exec_host") and response.exec_host != "localhost":
            import socket
            try:
                exec_host_name, dummy, dummy = socket.gethostbyaddr(
                    response.exec_host)
            except socket.error:
                exec_host_name = response.exec_host

            feedback_bits.append("".join(
                ["<p>",
                 _("Your code ran on %s.") % exec_host_name, "</p>"]))

        if hasattr(response, "stdout") and response.stdout:
            bulk_feedback_bits.append("".join([
                "<p>",
                _("Your code printed the following output"), ":"
                "<pre>%s</pre></p>"
            ]) % escape(response.stdout))
        if hasattr(response, "stderr") and response.stderr:
            bulk_feedback_bits.append("".join([
                "<p>",
                _("Your code printed the following error messages"), ":"
                "<pre>%s</pre></p>"
            ]) % escape(response.stderr))
        if hasattr(response, "figures") and response.figures:
            fig_lines = [
                "".join([
                    "<p>",
                    _("Your code produced the following plots"), ":</p>"
                ]),
                '<dl class="result-figure-list">',
            ]

            for nr, mime_type, b64data in response.figures:
                if mime_type in ["image/jpeg", "image/png"]:
                    fig_lines.extend([
                        "".join(["<dt>", _("Figure"), "%d<dt>"]) % nr,
                        '<dd><img alt="Figure %d" src="data:%s;base64,%s"></dd>'
                        % (nr, mime_type, b64data)
                    ])

            fig_lines.append("</dl>")
            bulk_feedback_bits.extend(fig_lines)

        # {{{ html output / santization

        if hasattr(response, "html") and response.html:

            def is_allowed_data_uri(allowed_mimetypes, uri):
                import re
                m = re.match(r"^data:([-a-z0-9]+/[-a-z0-9]+);base64,", uri)
                if not m:
                    return False

                mimetype = m.group(1)
                return mimetype in allowed_mimetypes

            def sanitize(s):
                import bleach

                def filter_audio_attributes(tag, name, value):
                    if name in ["controls"]:
                        return True
                    else:
                        return False

                def filter_source_attributes(tag, name, value):
                    if name in ["type"]:
                        return True
                    elif name == "src":
                        if is_allowed_data_uri([
                                "audio/wav",
                        ], value):
                            return bleach.sanitizer.VALUE_SAFE
                        else:
                            return False
                    else:
                        return False

                def filter_img_attributes(tag, name, value):
                    if name in ["alt", "title"]:
                        return True
                    elif name == "src":
                        return is_allowed_data_uri([
                            "image/png",
                            "image/jpeg",
                        ], value)
                    else:
                        return False

                if not isinstance(s, str):
                    return _("(Non-string in 'HTML' output filtered out)")

                return bleach.clean(s,
                                    tags=bleach.ALLOWED_TAGS +
                                    ["audio", "video", "source"],
                                    attributes={
                                        "audio": filter_audio_attributes,
                                        "source": filter_source_attributes,
                                        "img": filter_img_attributes,
                                    })

            bulk_feedback_bits.extend(
                sanitize(snippet) for snippet in response.html)

        # }}}

        return AnswerFeedback(correctness=correctness,
                              feedback="\n".join(feedback_bits),
                              bulk_feedback="\n".join(bulk_feedback_bits))
예제 #5
0
파일: flow.py 프로젝트: gboone/relate
def recalculate_session_grade(repo, course, session):
    """Only redoes the final grade determination without regrading
    individual pages.
    """

    if session.in_progress:
        raise RuntimeError(_("cannot recalculate grade on in-progress session"))

    prev_completion_time = session.completion_time

    session.append_comment(_("Session grade recomputed at %(time)s.") % {"time": format_datetime_local(local_now())})
    session.save()

    reopen_session(session, force=True, suppress_log=True)
    finish_flow_session_standalone(repo, course, session, force_regrade=False, now_datetime=prev_completion_time)
예제 #6
0
파일: flow.py 프로젝트: gboone/relate
def regrade_session(repo, course, session):
    if session.in_progress:
        fctx = FlowContext(repo, course, session.flow_id, flow_session=session)

        answer_visits = assemble_answer_visits(session)

        for i in range(len(answer_visits)):
            answer_visit = answer_visits[i]

            if answer_visit is not None and answer_visit.get_most_recent_grade():
                # Only make a new grade if there already is one.
                grade_page_visit(answer_visit, graded_at_git_commit_sha=fctx.course_commit_sha)
    else:
        prev_completion_time = session.completion_time

        session.append_comment(_("Session regraded at %(time)s.") % {"time": format_datetime_local(local_now())})
        session.save()

        reopen_session(session, force=True, suppress_log=True)
        finish_flow_session_standalone(repo, course, session, force_regrade=True, now_datetime=prev_completion_time)
예제 #7
0
파일: code.py 프로젝트: inducer/relate
    def grade(self, page_context, page_data, answer_data, grade_data):
        if answer_data is None:
            return AnswerFeedback(correctness=0,
                    feedback=_("No answer provided."))

        user_code = answer_data["answer"]

        # {{{ request run

        run_req = {"compile_only": False, "user_code": user_code}

        def transfer_attr(name):
            if hasattr(self.page_desc, name):
                run_req[name] = getattr(self.page_desc, name)

        transfer_attr("setup_code")
        transfer_attr("names_for_user")
        transfer_attr("names_from_user")

        run_req["test_code"] = self.get_test_code()

        if hasattr(self.page_desc, "data_files"):
            run_req["data_files"] = {}

            from course.content import get_repo_blob

            for data_file in self.page_desc.data_files:
                from base64 import b64encode
                run_req["data_files"][data_file] = \
                        b64encode(
                                get_repo_blob(
                                    page_context.repo, data_file,
                                    page_context.commit_sha).data).decode()

        try:
            response_dict = request_python_run_with_retries(run_req,
                    run_timeout=self.page_desc.timeout)
        except Exception:
            from traceback import format_exc
            response_dict = {
                    "result": "uncaught_error",
                    "message": "Error connecting to container",
                    "traceback": "".join(format_exc()),
                    }

        # }}}

        feedback_bits = []

        correctness = None

        if "points" in response_dict:
            correctness = response_dict["points"]
            try:
                feedback_bits.append(
                        "<p><b>%s</b></p>"
                        % _(get_auto_feedback(correctness)))
            except Exception as e:
                correctness = None
                response_dict["result"] = "setup_error"
                response_dict["message"] = (
                    "%s: %s" % (type(e).__name__, str(e))
                )

        # {{{ send email if the grading code broke

        if response_dict["result"] in [
                "uncaught_error",
                "setup_compile_error",
                "setup_error",
                "test_compile_error",
                "test_error"]:
            error_msg_parts = ["RESULT: %s" % response_dict["result"]]
            for key, val in sorted(response_dict.items()):
                if (key not in ["result", "figures"]
                        and val
                        and isinstance(val, six.string_types)):
                    error_msg_parts.append("-------------------------------------")
                    error_msg_parts.append(key)
                    error_msg_parts.append("-------------------------------------")
                    error_msg_parts.append(val)
            error_msg_parts.append("-------------------------------------")
            error_msg_parts.append("user code")
            error_msg_parts.append("-------------------------------------")
            error_msg_parts.append(user_code)
            error_msg_parts.append("-------------------------------------")

            error_msg = "\n".join(error_msg_parts)

            from relate.utils import local_now, format_datetime_local
            from course.utils import LanguageOverride
            with LanguageOverride(page_context.course):
                from relate.utils import render_email_template
                message = render_email_template(
                    "course/broken-code-question-email.txt", {
                        "site": getattr(settings, "RELATE_BASE_URL"),
                        "page_id": self.page_desc.id,
                        "course": page_context.course,
                        "error_message": error_msg,
                        "review_uri": page_context.page_uri,
                        "time": format_datetime_local(local_now())
                    })

                if (
                        not page_context.in_sandbox
                        and not is_nuisance_failure(response_dict)):
                    try:
                        from django.core.mail import EmailMessage
                        msg = EmailMessage("".join(["[%s:%s] ",
                            _("code question execution failed")])
                            % (
                                page_context.course.identifier,
                                page_context.flow_session.flow_id
                                if page_context.flow_session is not None
                                else _("<unknown flow>")),
                            message,
                            settings.ROBOT_EMAIL_FROM,
                            [page_context.course.notify_email])

                        from relate.utils import get_outbound_mail_connection
                        msg.connection = get_outbound_mail_connection("robot")
                        msg.send()

                    except Exception:
                        from traceback import format_exc
                        feedback_bits.append(
                            six.text_type(string_concat(
                                "<p>",
                                _(
                                    "Both the grading code and the attempt to "
                                    "notify course staff about the issue failed. "
                                    "Please contact the course or site staff and "
                                    "inform them of this issue, mentioning this "
                                    "entire error message:"),
                                "</p>",
                                "<p>",
                                _(
                                    "Sending an email to the course staff about the "
                                    "following failure failed with "
                                    "the following error message:"),
                                "<pre>",
                                "".join(format_exc()),
                                "</pre>",
                                _("The original failure message follows:"),
                                "</p>")))

        # }}}

        if hasattr(self.page_desc, "correct_code"):
            def normalize_code(s):
                return (s
                        .replace(" ", "")
                        .replace("\r", "")
                        .replace("\n", "")
                        .replace("\t", ""))

            if (normalize_code(user_code)
                    == normalize_code(self.page_desc.correct_code)):
                feedback_bits.append(
                        "<p><b>%s</b></p>"
                        % _("It looks like you submitted code that is identical to "
                            "the reference solution. This is not allowed."))

        from relate.utils import dict_to_struct
        response = dict_to_struct(response_dict)

        bulk_feedback_bits = []

        if response.result == "success":
            pass
        elif response.result in [
                "uncaught_error",
                "setup_compile_error",
                "setup_error",
                "test_compile_error",
                "test_error"]:
            feedback_bits.append("".join([
                "<p>",
                _(
                    "The grading code failed. Sorry about that. "
                    "The staff has been informed, and if this problem is "
                    "due to an issue with the grading code, "
                    "it will be fixed as soon as possible. "
                    "In the meantime, you'll see a traceback "
                    "below that may help you figure out what went wrong."
                    ),
                "</p>"]))
        elif response.result == "timeout":
            feedback_bits.append("".join([
                "<p>",
                _(
                    "Your code took too long to execute. The problem "
                    "specifies that your code may take at most %s seconds "
                    "to run. "
                    "It took longer than that and was aborted."
                    ),
                "</p>"])
                    % self.page_desc.timeout)

            correctness = 0
        elif response.result == "user_compile_error":
            feedback_bits.append("".join([
                "<p>",
                _("Your code failed to compile. An error message is "
                    "below."),
                "</p>"]))

            correctness = 0
        elif response.result == "user_error":
            feedback_bits.append("".join([
                "<p>",
                _("Your code failed with an exception. "
                    "A traceback is below."),
                "</p>"]))

            correctness = 0
        else:
            raise RuntimeError("invalid runpy result: %s" % response.result)

        if hasattr(response, "feedback") and response.feedback:
            def sanitize(s):
                import bleach
                return bleach.clean(s, tags=["p", "pre"])
            feedback_bits.append("".join([
                "<p>",
                _("Here is some feedback on your code"),
                ":"
                "<ul>%s</ul></p>"]) %
                        "".join(
                            "<li>%s</li>" % sanitize(fb_item)
                            for fb_item in response.feedback))
        if hasattr(response, "traceback") and response.traceback:
            feedback_bits.append("".join([
                "<p>",
                _("This is the exception traceback"),
                ":"
                "<pre>%s</pre></p>"]) % escape(response.traceback))
        if hasattr(response, "exec_host") and response.exec_host != "localhost":
            import socket
            try:
                exec_host_name, dummy, dummy = socket.gethostbyaddr(
                        response.exec_host)
            except socket.error:
                exec_host_name = response.exec_host

            feedback_bits.append("".join([
                "<p>",
                _("Your code ran on %s.") % exec_host_name,
                "</p>"]))

        if hasattr(response, "stdout") and response.stdout:
            bulk_feedback_bits.append("".join([
                "<p>",
                _("Your code printed the following output"),
                ":"
                "<pre>%s</pre></p>"])
                    % escape(response.stdout))
        if hasattr(response, "stderr") and response.stderr:
            bulk_feedback_bits.append("".join([
                "<p>",
                _("Your code printed the following error messages"),
                ":"
                "<pre>%s</pre></p>"]) % escape(response.stderr))
        if hasattr(response, "figures") and response.figures:
            fig_lines = ["".join([
                "<p>",
                _("Your code produced the following plots"),
                ":</p>"]),
                '<dl class="result-figure-list">',
                ]

            for nr, mime_type, b64data in response.figures:
                if mime_type in ["image/jpeg", "image/png"]:
                    fig_lines.extend([
                        "".join([
                            "<dt>",
                            _("Figure"), "%d<dt>"]) % nr,
                        '<dd><img alt="Figure %d" src="data:%s;base64,%s"></dd>'
                        % (nr, mime_type, b64data)])

            fig_lines.append("</dl>")
            bulk_feedback_bits.extend(fig_lines)

        # {{{ html output / santization

        if hasattr(response, "html") and response.html:
            def is_allowed_data_uri(allowed_mimetypes, uri):
                import re
                m = re.match(r"^data:([-a-z0-9]+/[-a-z0-9]+);base64,", uri)
                if not m:
                    return False

                mimetype = m.group(1)
                return mimetype in allowed_mimetypes

            def sanitize(s):
                import bleach

                def filter_audio_attributes(tag, name, value):
                    if name in ["controls"]:
                        return True
                    else:
                        return False

                def filter_source_attributes(tag, name, value):
                    if name in ["type"]:
                        return True
                    elif name == "src":
                        if is_allowed_data_uri([
                                "audio/wav",
                                ], value):
                            return bleach.sanitizer.VALUE_SAFE
                        else:
                            return False
                    else:
                        return False

                def filter_img_attributes(tag, name, value):
                    if name in ["alt", "title"]:
                        return True
                    elif name == "src":
                        return is_allowed_data_uri([
                            "image/png",
                            "image/jpeg",
                            ], value)
                    else:
                        return False

                if not isinstance(s, six.text_type):
                    return _("(Non-string in 'HTML' output filtered out)")

                return bleach.clean(s,
                        tags=bleach.ALLOWED_TAGS + ["audio", "video", "source"],
                        attributes={
                            "audio": filter_audio_attributes,
                            "source": filter_source_attributes,
                            "img": filter_img_attributes,
                            })

            bulk_feedback_bits.extend(
                    sanitize(snippet) for snippet in response.html)

        # }}}

        return AnswerFeedback(
                correctness=correctness,
                feedback="\n".join(feedback_bits),
                bulk_feedback="\n".join(bulk_feedback_bits))