def export_records(field_definitions, records):
    stream = cStringIO.StringIO()
    try:
        workbook = Workbook()
        sheet = workbook.add_sheet('Exported Records')
        #admin = workbook.add_sheet('Metadata')
        # write_metadata()
        write_header(sheet, field_definitions)
        for row, record in enumerate(records):
            sheet.write(row+1, 0, record.id)
            if record.filename != None:
                sheet.write(row+1, 1, str(record.filename))
            log.critical(record.id)
            for col, definition in enumerate(field_definitions):
                data = simplejson.loads(record.data) if record.data else dict()
                value = get_value(data.get(definition.identifier, None))
                if value is not None:
                    sheet.write(row+1, col+2, value)
        workbook.save(stream)
        return stream.getvalue()
    finally:
        stream.close()


def write_header(sheet, field_definitions):
    sheet.write(0, 0, 'SSID')
    sheet.write(0, 1, 'Filename')
    for col, definition in enumerate(field_definitions):
        sheet.write(0, col+1, "%s[%d]" % (definition.label, definition.id))