Export Django model as CSV

djenv.py

'''

Usage:

export DJANGO_SETTINGS_MODULE=project_name.settings
djcsv.py someapp.models.SomeModel > output.csv

Run "djenv.py -h" for full help.


'''

import importlib
import argparse
import csv
import sys

import django
django.setup()

DEFAULT_COUNT = 1000

def get_args():
    parser = argparse.ArgumentParser()
    parser.add_argument('dotted_path')
    parser.add_argument('-c', '--count', default=DEFAULT_COUNT, type=int,
                        help='Export the most recent COUNT records (highest PKs)')
    parser.add_argument('--all', action='store_true', default=False,
                        help='Export all records. Overrides --count')
    return parser.parse_args()

def load_model_class(dotted_path):
    split_pos = dotted_path.rfind('.')
    assert split_pos > 0, dotted_path
    module_name, model_class_name = dotted_path[:split_pos], dotted_path[split_pos+1:]
    module = importlib.import_module(module_name)
    model_class = getattr(module, model_class_name)
    return model_class

def field_names(model_class):
    return [
        field.name
        for field in
        model_class._meta.get_fields()
        ]

if __name__ == '__main__':
    args = get_args()
    model_class = load_model_class(args.dotted_path)
    fields = field_names(model_class)
    csv_out = csv.DictWriter(sys.stdout, fields)
    csv_out.writeheader()
    if args.all:
        records = model_class.objects.all()
    else:
        records = model_class.objects.order_by('-pk')[:args.count]
    for record in records:
        csv_out.writerow({
            field: getattr(record, field)
            for field in fields
            })