DateTime issues in django xlsxwriter

Question

I am trying to create an export to excel functionality in my django view as follows:

def export_myreport(request, sd, ed):
    from xlsxwriter.workbook import Workbook
    import cStringIO as StringIO
    from django.utils.encoding import smart_str

    # create a workbook in memory
    output = StringIO.StringIO()

    wb = Workbook(output)

    bg = wb.add_format({'bg_color': '#9CB640', 'font_color': 'black'})
    bg2 = wb.add_format({'bg_color': '#FFFFFF', 'font_color': 'black'})

    ws = wb.add_worksheet('My Report')

    row_num = 0

    summary = MyModel.objects.filter(time__range = (sd, ed)).select_related()

    row_num += 2
    row = [
        smart_str(u"Time"),
        smart_str(u"Item"),
        smart_str(u"User")
    ]
    for col_num in xrange(len(row)):
        ws.write(row_num, col_num, row[col_num], bg)

    for s in summary:
        row_num += 1
        row2 = [
            s.time,
            s.model_name,
            s.user.first_name
        ]
        for col_num in xrange(len(row2)):
            ws.write(row_num, col_num, row2[col_num], bg2)

    wb.close()

    output.seek(0)
    response = HttpResponse(output.read(), content_type="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
    response['Content-Disposition'] = "attachment; filename=myreport.xlsx"

    return response

But i am getting some issues with the DateTime formatting! Perhaps something i am missing here?

Here is the error i get:

TypeError at /myapp/export_myreport/2015-05-01/2015-05-19
can't subtract offset-naive and offset-aware datetimes

EDIT:

This is how i am calling the url in my html:

<a href="export_myreport/{{begindate}}/{{enddate}}" class="btn btn-default pull-right" role="button">Export to XLSX</a>

Here the {{begindate}} and {{enddate}} are angular variables.

Answer 1

Excel, and thus XlsxWriter, doesn't support timezones in dates/times.

So you will need to remove or adjust the timezone from the datetime before passing it to XlsxWriter.

Something like this from the pytz docs:

dt = datetime(2005, 3, 1, 14, 13, 21, tzinfo=utc)
naive = dt.replace(tzinfo=None)

Probably this would be better handled in Django though rather than adjusting all datetime data prior to passing it to XlsxWriter. Maybe someone else can add a suggestion on that.