Exports need to include a BOM

Currently exporting a CSV and opening it in Excel ruins any unicode characters.

For example, Japanese characters display as 裕太

Exporter needs to do something like this to write the BOM to the beginning of the file;

    contents = StringIO()
    contents.write(codecs.BOM_UTF8.decode('utf-8'))
    writer = csv.writer(contents)

[legios89]

Actually, we also stumbled into this problem in our place. What we did is the following

We improved the built in exporter a little bit

from explorer.exporters import CSVExporter
from io import BytesIO


class CSVExporterBOM(CSVExporter):
    def _get_output(self, res, **kwargs):
        csv_data = super(CSVExporterBOM, self)._get_output(res, **kwargs)
        csv_data_io = BytesIO()
        csv_data_io.write(b'\xef\xbb\xbf')
        csv_data_io.write(csv_data.getvalue().encode('utf-8'))
        return csv_data_io

than we set this as the CSV exporter in the settings

EXPLORER_DATA_EXPORTERS = [
    ('csv', 'core.exporters.CSVExporterBOM'),
    ('excel', 'explorer.exporters.ExcelExporter'),
    ('json', 'explorer.exporters.JSONExporter')
]

So this is an existing problem I think, it was just easy to fix it like this.

[bdista]

Ok great, I’ll prepare a PR, thanks!