Django Queryset CSV Exporter

export.py

class CSVExport(object):
    """
    A generic CSV exporter for any queryset. Use with a 
    file object or the default storage class.
    
    Use with a file object:
        queryset = SomeModel.objects.all()
        exporter = CSVExport(queryset)
        export.export(file)
        
    Use with the default storage class, give a location and filename
        queryset = SomeModel.objects.all()
        exporter = CSVExport(queryset)
        export.export_to_filepath(location, 'somefile.csv')
        
    Specify the fields in the constructor:
        exporter = CSVExport(queryset, fields)
        
        where fields is a list of field names. If not given,
        defaults to the field names of the first object in the queryset.
    """
    def __init__(self, queryset, fields=None):
        self.queryset = queryset
        self.fields = None
        
    def export_to_filepath(self, location, filename):
        """
        export to a file as given in the path. will
        create a file using Django's storage class,
        and call export() on it
        """
        storage_class = get_storage_class()
        file = storage_class(location=location)
        with open(file.path(filename), 'wb') as f:
            self.export(f)
        
    def export(self, fileobj, header=True):
        """
        export the queryset into file. 
        :param file: the file object to use
        :return: the csv.writer instance
        """
        # create a CSV writer
        writer = csv.writer(fileobj)
        # get fields 
        fields = self.fields
        if not fields:
            first = self.queryset[0]
            fields = [f.name for f in first._meta.fields]
        # write header
        if header:
            writer.writerow(fields)
        # write data
        for obj in self.queryset:
            writer.writerow([getattr(obj, f) for f in fields])
        return writer