Downloading the list of users from sysadmin/dashboard triggers a 500 error

[regisb]

Bug description

It's impossible to download the CSV list of users from the sysadmin dashboard.

How to reproduce

1. Go to http://local.overhang.io:8000/sysadmin/
2. Click "download list of all users (csv file)"
3. A 500 error is generated.

Here are the logs from the LMS:

Internal Server Error: /sysadmin/                                                                                                                             
Traceback (most recent call last):                                                                                                                            
  File "/openedx/venv/lib/python3.5/site-packages/django/core/handlers/exception.py", line 34, in inner                                                       
    response = get_response(request)                                                                                                                          
  File "/openedx/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 115, in _get_response                                                   
    response = self.process_exception_by_middleware(e, request)                                                                                               
  File "/openedx/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 113, in _get_response                                                   
    response = wrapped_callback(request, *callback_args, **callback_kwargs)                                                                                   
  File "/opt/pyenv/versions/3.5.9/lib/python3.5/contextlib.py", line 30, in inner                                                                             
    return func(*args, **kwds)                                                                                                                                
  File "/openedx/venv/lib/python3.5/site-packages/django/views/generic/base.py", line 71, in view                                                             
    return self.dispatch(request, *args, **kwargs)                                                                                                            
  File "/openedx/venv/lib/python3.5/site-packages/django/utils/decorators.py", line 45, in _wrapper                                                           
    return bound_method(*args, **kwargs)                                                                                                                      
  File "/openedx/venv/lib/python3.5/site-packages/django/utils/decorators.py", line 142, in _wrapped_view                                                     
    response = view_func(request, *args, **kwargs)                                                                                                            
  File "/openedx/venv/lib/python3.5/site-packages/django/utils/decorators.py", line 45, in _wrapper                                                           
    return bound_method(*args, **kwargs)                                                                                                                      
  File "/openedx/venv/lib/python3.5/site-packages/django/contrib/auth/decorators.py", line 21, in _wrapped_view                                               
    return view_func(request, *args, **kwargs)                                                                                                                
  File "/openedx/venv/lib/python3.5/site-packages/django/utils/decorators.py", line 45, in _wrapper                                                           
    return bound_method(*args, **kwargs)                                                                                                                      
  File "/openedx/venv/lib/python3.5/site-packages/django/views/decorators/cache.py", line 31, in _cache_controlled                                            
    response = viewfunc(request, *args, **kw)                                                                                                                 
  File "/openedx/venv/lib/python3.5/site-packages/django/utils/decorators.py", line 45, in _wrapper                                                           
    return bound_method(*args, **kwargs)                                                                                                                      
  File "/openedx/venv/lib/python3.5/site-packages/django/views/decorators/http.py", line 99, in inner
    response = func(request, *args, **kwargs)
  File "/openedx/edx-platform/lms/djangoapps/dashboard/sysadmin.py", line 67, in dispatch
    return super(SysadminDashboardView, self).dispatch(*args, **kwargs)
  File "/openedx/venv/lib/python3.5/site-packages/django/views/generic/base.py", line 97, in dispatch
    return handler(request, *args, **kwargs)
  File "/openedx/edx-platform/lms/djangoapps/dashboard/sysadmin.py", line 219, in post
    request.META['SERVER_NAME']), header, data)
  File "/openedx/edx-platform/lms/djangoapps/dashboard/sysadmin.py", line 84, in return_csv
    writer.writerow(header)
  File "/openedx/venv/lib/python3.5/site-packages/unicodecsv/py3.py", line 28, in writerow
    return self.writer.writerow(row)
  File "/openedx/venv/lib/python3.5/site-packages/unicodecsv/py3.py", line 15, in write
    return self.binary.write(string.encode(self.encoding, self.errors))
TypeError: string argument expected, got 'bytes'

This is a minimal piece of code that reproduces the error:

from six import StringIO
import unicodecsv as csv
writer = csv.writer(csv_file, dialect='excel', quotechar='"', quoting=csv.QUOTE_ALL)
writer.writerow(["username", "email"])

This piece of code can be fixed by replacing the "unicodecsv" library, which was made for python 2, by the standard csv library:

from six import StringIO
import csv
writer = csv.writer(csv_file, dialect='excel', quotechar='"', quoting=csv.QUOTE_ALL)
writer.writerow(["username", "email"])

This is an upstream issue with edx-platform. We should address this issue by replacing unicodecsv by csv pretty much everywhere. We should also add some unit tests to make sure there is no regression.

Environment

➭ tutor --version
tutor, version 10.0.11

Additional context

See conversation: https://discuss.overhang.io/t/tutor-10-0-11-sysadmin-feature-generates-500-error/776

[regisb]

Closing this as the sysadmin dashboard is slated for deprecation https://app.slack.com/client/T02SNA1T6/CK94QNCQ0