bjdata 0.2.0

Binary JData and UBJSON encoder/decoder

Binary JData for Python - a lightweight binary JSON format

• Copyright: (C) Qianqian Fang (2020) <q.fang at neu.edu>
• Copyright: (C) Iotic Labs Ltd. (2019) <vilnis.termanis at iotic-labs.com>
• License: Apache License, Version 2.0
• Version: 0.2
• URL: https://github.com/fangq/pybj

This is a Python v3.2+ (and 2.7+) Binary JData based on the Draft-1 specification.

Installing / packaging

## To get from PyPI
pip3 install bjdata

## To only build extension modules inline (e.g. in repository)
python3 setup.py build_ext -i

## To build & install globally
python3 setup.py install

## To skip building of extensions when installing (or building)
PYBJDATA_NO_EXTENSION=1 python3 setup.py install

Notes

• The extension module is not required but provide a significant speed boost.
• The above can also be run with v2.7+
• At run time, one can check whether compiled version is in use via the bjdata.EXTENSION_ENABLED boolean

Usage

It's meant to behave very much like Python's built-in JSON module, e.g.:

import bjdata as bj

encoded = bj.dumpb({u'a': 1})

decoded = bj.loadb(encoded)

Note: Only unicode strings in Python 2 will be encoded as strings, plain str will be encoded as a byte array.

Documentation

import bjdata
help(bjdata.dump)
help(bjdata.load)

Command-line utility

This converts between JSON and BJData formats:

python3 -mbjdata
USAGE: bjdata (fromjson|tojson) (INFILE|-) [OUTFILE]

Tests

Static

This library has been checked using flake8 and pylint, using a modified configuration - see pylint.rc and flake8.cfg.

Unit

python3 -mvenv py
. py/bin/activate
pip install -U pip setuptools
pip install -e .[dev]

./coverage_test.sh

Note: See coverage_test.sh for additional requirements.

Limitations

• The No-Op type is only supported by the decoder. (This should arguably be a protocol-level rather than serialisation-level option.) Specifically, it is only allowed to occur at the start or between elements of a container and only inside un-typed containers. (In a typed container it is impossible to tell the difference between an encoded element and a No-Op.)
• Strongly-typed containers are only supported by the decoder (apart from for bytes/bytearray) and not for No-Op.
• Encoder/decoder extensions are not supported at this time.

Acknowledgement

This package was modified based on the py-ubjson package developed by Iotic Labs Ltd. Project URL: https://github.com/Iotic-Labs/py-ubjson

The major changes were focused on supporting the Binary JData Specification Draft 1 - an extended Universal Binary JSON (UBJSON) Specification Draft-12 by adding the below new features:

• BJData adds 4 new numeric data types: uint16 [u], uint32 [m], uint64 [M] and float16 [h]
• BJData supports an optimized ND array container
• BJData does not convert NaN/Inf/-Inf to null