CDJS (Custom Datetime JSON Serializer)

cdjs is an extension for orjson to serialize datetime (and other types) in a fast custom way.

By default orjson serializes datetime according to RFC 3339 format which sometimes may not suit. orjson provides a mean to process datetime using custom serializer (via OPT_PASSTHROUGH_DATETIME flag and via default=custom_datetime_serializer). Serializers implemented in Python are usually not fast enough, that's the reason behind implementation of the custom datetime serializer written in Rust to gain optimal speed.

Aside from datetimes, cdjs is an attempt to port bson.json_util.default() and to use with orjson as a default handler.

At the moment serialization of the following types are supported:

• datetime
• bson.ObjectId

Example

import datetime
import hashlib

from bson import ObjectId
from cdjs import serialize
import orjson

mydata = {
    '_id': ObjectId(hashlib.md5(b'test').hexdigest()[:24]),
    'date': datetime.datetime(2021, 1, 1, hour=0, minute=4, second=36, microsecond=123000)
}
orjson.dumps(mydata, option=orjson.OPT_PASSTHROUGH_DATETIME, default=serialize)

# b'{"_id":{"$oid":"098f6bcd4621d373cade4e83"},"date":{"$date":"2021-01-01T00:04:36.123Z"}}'

Benchmarks

To run benchmark:

pip install -r bench-requirements.txt
python tests/benchmark.py --help
python tests/benchmark.py --scenario utc_dates

Installation

pip install cdjs

Building

To make a develop build

NOTE: Develop build doesn't enable optimizations, hence the result may work slow.

python ./setup.py develop

To make a release build

Pre-requisites

# switch to nightly channel
RUSTUP_USE_CURL=1 rustup default nightly-2021-01-31
pip install maturin

To compile, package and publish to PyPI

maturin build --no-sdist --release --strip --manylinux off
maturin publish

Testing

To run tests

python -m unittest -v tests.test_serialization

Python/OS Version Support

• Python 3.6 (tested)
• Python 3.7+ (not tested)
• Linux (with GLib 2.17+)