1+ #
2+ # Copyright (c) 2014-2015 Harvard, edX & OpenCraft
3+ #
4+ # This software's license gives you freedom; you can copy, convey,
5+ # propagate, redistribute and/or modify this program under the terms of
6+ # the GNU Affero General Public License (AGPL) as published by the Free
7+ # Software Foundation (FSF), either version 3 of the License, or (at your
8+ # option) any later version of the AGPL published by the FSF.
9+ #
10+ # This program is distributed in the hope that it will be useful, but
11+ # WITHOUT ANY WARRANTY; without even the implied warranty of
12+ # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
13+ # General Public License for more details.
14+ #
15+ # You should have received a copy of the GNU Affero General Public License
16+ # along with this program in a file in the toplevel directory called
17+ # "AGPLv3". If not, see <http://www.gnu.org/licenses/>.
18+ #
19+ """
20+ Instructor Tool: An XBlock for instructors to export student answers from a course.
21+
22+ All processing is done offline.
23+ """
24+ import json
25+ import pkg_resources
26+
27+ from django .utils .translation import gettext_noop as _
28+ from web_fragments .fragment import Fragment
29+ from xblock .core import XBlock
30+ from xblock .exceptions import JsonHandlerError
31+ from xblock .fields import Dict , Scope , String
32+ from xblock .utils .resources import ResourceLoader
33+
34+ loader = ResourceLoader (__name__ )
35+
36+
37+ @XBlock .wants ('user' )
38+ class DataExportXBlock (XBlock ):
39+ icon_class = "problem"
40+ display_name = String (
41+ display_name = _ ("(Display name)" ),
42+ help = _ ("Title to display" ),
43+ default = _ ("Data export" ),
44+ scope = Scope .settings
45+ )
46+ active_export_task_id = String (
47+ # The UUID of the celery AsyncResult for the most recent export,
48+ # IF we are sill waiting for it to finish
49+ default = "" ,
50+ scope = Scope .user_state ,
51+ )
52+ last_export_result = Dict (
53+ # The info dict returned by the most recent successful export.
54+ # If the export failed, it will have an "error" key set.
55+ default = None ,
56+ scope = Scope .user_state ,
57+ )
58+
59+ has_author_view = True
60+
61+ def author_view (self , context = None ):
62+ """ Studio View """
63+ # Warn the user that this block will only work from the LMS. (Since the CMS uses
64+ # different celery queues; our task listener is waiting for tasks on the LMS queue)
65+ return Fragment ('<p>Data Export Block</p><p>This block only works from the LMS.</p>' )
66+
67+ def studio_view (self , context = None ):
68+ """ View for editing Instructor Tool block in Studio. """
69+ # Display friendly message explaining that the block is not editable.
70+ return Fragment ('<p>This is a preconfigured block. It is not editable.</p>' )
71+
72+ def check_pending_export (self ):
73+ """
74+ If we're waiting for an export, see if it has finished, and if so, get the result.
75+ """
76+ from .tasks import export_data as export_data_task
77+ if self .active_export_task_id :
78+ async_result = export_data_task .AsyncResult (self .active_export_task_id )
79+ if async_result .ready ():
80+ self ._save_result (async_result )
81+
82+ def _save_result (self , task_result ):
83+ """ Given an AsyncResult or EagerResult, save it. """
84+ self .active_export_task_id = ''
85+ if task_result .successful ():
86+ self .last_export_result = task_result .result
87+ else :
88+ self .last_export_result = {'error' : str (task_result .result )}
89+
90+ def resource_string (self , path ):
91+ """Handy helper for getting resources from our kit."""
92+ data = pkg_resources .resource_string (__name__ , path )
93+ return data .decode ("utf8" )
94+
95+ def student_view (self , context = None ):
96+ """ Normal View """
97+ if not self .user_is_staff ():
98+ return Fragment ('<p>This interface can only be used by course staff.</p>' )
99+
100+ html = loader .render_django_template ('templates/export.html' )
101+ frag = Fragment (html )
102+ frag .add_javascript (self .resource_string ("static/js/src/export.js" ))
103+ frag .initialize_js ('DataExportXBlock' )
104+ return frag
105+
106+ @property
107+ def download_url_for_last_report (self ):
108+ """ Get the URL for the last report, if any """
109+ # Unfortunately this is a bit inefficient due to the ReportStore API
110+ if not self .last_export_result or 'error' in self .last_export_result :
111+ return None
112+ from lms .djangoapps .instructor_task .models import ReportStore
113+ report_store = ReportStore .from_config (config_name = 'GRADES_DOWNLOAD' )
114+ course_key = getattr (self .scope_ids .usage_id , 'course_key' , None )
115+ return dict (report_store .links_for (course_key )).get (self .last_export_result ['report_filename' ])
116+
117+ def _get_status (self ):
118+ self .check_pending_export ()
119+ return {
120+ 'export_pending' : bool (self .active_export_task_id ),
121+ 'last_export_result' : self .last_export_result ,
122+ 'download_url' : self .download_url_for_last_report ,
123+ }
124+
125+ def raise_error (self , code , message ):
126+ """
127+ Raises an error and marks the block with a simulated failed task dict.
128+ """
129+ self .last_export_result = {
130+ 'error' : message ,
131+ }
132+ self .display_data = None
133+ raise JsonHandlerError (code , message )
134+
135+ @XBlock .json_handler
136+ def get_status (self , data , suffix = '' ):
137+ return self ._get_status ()
138+
139+ @XBlock .json_handler
140+ def delete_export (self , data , suffix = '' ):
141+ self ._delete_export ()
142+ return self ._get_status ()
143+
144+ def _delete_export (self ):
145+ self .last_export_result = None
146+ self .display_data = None
147+ self .active_export_task_id = ''
148+
149+ @XBlock .json_handler
150+ def start_export (self , data , suffix = '' ):
151+ """ Start a new asynchronous export """
152+ if not self .user_is_staff ():
153+ raise JsonHandlerError (403 , "Permission denied." )
154+
155+ # Launch task
156+ from .tasks import export_data as export_data_task
157+ self ._delete_export ()
158+ # Make sure we nail down our state before sending off an asynchronous task.
159+ self .save ()
160+ async_result = export_data_task .delay (
161+ # course_id not available in workbench.
162+ str (getattr (self .runtime , 'course_id' , 'course_id' )),
163+ )
164+ if async_result .ready ():
165+ # In development mode, the task may have executed synchronously.
166+ # Store the result now, because we won't be able to retrieve it later :-/
167+ if async_result .successful ():
168+ # Make sure the result can be represented as JSON, since the non-eager celery
169+ # requires that
170+ json .dumps (async_result .result )
171+ self ._save_result (async_result )
172+ else :
173+ # The task is running asynchronously. Store the result ID so we can query its progress:
174+ self .active_export_task_id = async_result .id
175+ return self ._get_status ()
176+
177+ @XBlock .json_handler
178+ def cancel_export (self , request , suffix = '' ):
179+ from .tasks import export_data as export_data_task
180+ if self .active_export_task_id :
181+ async_result = export_data_task .AsyncResult (self .active_export_task_id )
182+ async_result .revoke ()
183+ self ._delete_export ()
184+
185+ def _get_user_attr (self , attr ):
186+ """Get an attribute of the current user."""
187+ user_service = self .runtime .service (self , 'user' )
188+ if user_service :
189+ # May be None when creating bok choy test fixtures
190+ return user_service .get_current_user ().opt_attrs .get (attr )
191+ return None
192+
193+ def user_is_staff (self ):
194+ """Return a Boolean value indicating whether the current user is a member of staff."""
195+ return self ._get_user_attr ('edx-platform.user_is_staff' )
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