json50.10.0
Published
A Python implementation of the JSON5 data format.
pip install json5
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Requires Python
>=3.8.0
pyjson5
A Python implementation of the JSON5 data format.
JSON5 extends the JSON data interchange format to make it slightly more usable as a configuration language:
-
JavaScript-style comments (both single and multi-line) are legal.
-
Object keys may be unquoted if they are legal ECMAScript identifiers
-
Objects and arrays may end with trailing commas.
-
Strings can be single-quoted, and multi-line string literals are allowed.
There are a few other more minor extensions to JSON; see the above page for the full details.
This project implements a reader and writer implementation for Python; where possible, it mirrors the standard Python JSON API package for ease of use.
There is one notable difference from the JSON api: the load()
and
loads()
methods support optionally checking for (and rejecting) duplicate
object keys; pass allow_duplicate_keys=False
to do so (duplicates are
allowed by default).
This is an early release. It has been reasonably well-tested, but it is SLOW. It can be 1000-6000x slower than the C-optimized JSON module, and is 200x slower (or more) than the pure Python JSON module.
Please Note: This library only handles JSON5 documents, it does not allow you to read arbitrary JavaScript. For example, bare integers can be legal object keys in JavaScript, but they aren't in JSON5.
Known issues
-
Did I mention that it is SLOW?
-
The implementation follows Python3's
json
implementation where possible. This means that theencoding
method todump()
is ignored, and unicode strings are always returned. -
The
cls
keyword argument thatjson.load()
/json.loads()
accepts to specify a custom subclass ofJSONDecoder
is not and will not be supported, because this implementation uses a completely different approach to parsing strings and doesn't have anything like theJSONDecoder
class. -
The
cls
keyword argument thatjson.dump()
/json.dumps()
accepts is also not supported, for consistency withjson5.load()
. Thedefault
keyword is supported, though, and might be able to serve as a workaround.
Contributing
On Mac
The easiest thing to do is to install uv
and
use uv
and the //run
script to develop things. See ./run --help
for
the various commands that are supported. glop
is the parser generator
tool used to generate a parser from the grammar in json5/json5.g
.
$ brew install uv
$ git clone https://github.com/dpranke/pyjson5
$ git clone https://github.com/dpranke/glop
$ cd pyjson5
$ source $(./run devenv) # To activate a venv w/ all the needed dev tools.
On other platforms
Install uv
via whatever mechanism is appropriate.
Running the tests
$ ./run tests
Updating the packages
# Update the version in json5/version.py to $VERSION, which should be of
# the form X.Y.Z where X, Y, and Z are numbers.
$ git commit -a -m "Bump the version to $VERSION"
$ ./run regen
$ ./run presubmit
$ git tag "v$VERSION"
$ ./run build
$ ./run publish --prod
$ git push origin
$ git push --tags origin
(Assuming you have upload privileges to PyPI and the GitHub repo, of course.)
Version History / Release Notes
-
v0.10.0 (2024-11-25)
- GitHub issue #57.
Added a
JSON5Encoder
class that can be overridden to do custom encoding of values. This class is vaguely similar to theJSONEncoder
class in the standardjson
library, except that it has anencode()
method that can be overridden to customize any value, not just ones the standard encoder doesn't know how to handle. It does also support adefault()
method that can be used to encode things not normally encodable, like the JSONEncoder class. It does not support aniterencode
method. One could probably be added in the future, although exactly how that would work and interact withencode
is a little unclear. - Restructured the code to use the new encoder class; doing so actually allowed me to delete a bunch of tediously duplicative code.
- Added a new
quote_style
argument todump()
/dumps()
to control how strings are encoded by default. For compatibility with older versions of the json5 library and the standard json library, it usesQuoteStyle.ALWAYS_DOUBLE
which encodes all strings with double quotes all the time. You can also configure it to use single quotes all the time (ALWAYS_SINGLE
), and to switch between single and double when doing so eliminates a need to escape quotes (PREFER_SINGLE
andPREFER_DOUBLE
). This also adds a--quote-style
argument topython -m json5
. - This release has a fair number of changes, but is intended to be completely backwards-compatible. Code without changes should run exactly as it did before.
- GitHub issue #57.
Added a
-
v0.9.28 (2024-11-11)
- Fix GitHub CI to install
uv
so./run tests
works properly. - Mark Python3.13 as supported in package metadata.
- Update dev package dependencies (note that the latest versions of coverage and pylint no longer work w/ Python3.8)
- Fix GitHub CI to install
-
v0.9.27 (2024-11-10)
- Fix typo in //README.md
-
v0.9.26 (2024-11-10)
- GitHub issue #82
Add support for the
strict
parameter toload()
/loads()
. - Significantly rework the infra and the
run
script to be contemporary.
- GitHub issue #82
Add support for the
-
v0.9.25 (2024-04-12)
- GitHub issue #81 Explicitly specify the directory to use for the package in pyproject.toml.
-
v0.9.24 (2024-03-16)
- Update GitHub workflow config to remove unnecessary steps and run on pull requests as well as commits.
- Added note about removing
hypothesize
in v0.9.23. - No code changes.
-
v0.9.23 (2024-03-16)
- Lots of cleanup:
- Removed old code needed for Python2 compatibility.
- Removed tests using
hypothesize
. This ran model-based checks and didn't really add anything useful in terms of coverage to the test suite, and it introduced dependencies and slowed down the tests significantly. It was a good experiment but I think we're better off without it. - Got everything linting cleanly with pylint 3.1 and
ruff check
using ruff 0.3.3 (Note that commit message in 00d73a3 says pylint 3.11, which is a typo). - Code reformatted with
ruff format
- Added missing tests to bring coverage up to 100%.
- Lots of minor code changes as the result of linting and coverage testing, but no intentional functional differences.
- Lots of cleanup:
-
v0.9.22 (2024-03-06)
- Attempt to fix the GitHub CI configuration now that setup.py is gone. Also, test on 3.12 instead of 3.11.
- No code changes.
-
v0.9.21 (2024-03-06)
- Moved the benchmarks/*.json data files' license information to //LICENSE to (hopefully) make the Google linter happy.
-
v0.9.20 (2024-03-03)
- Added
json5.__version__
in addition tojson5.VERSION
. - More packaging modernization (no more setup.{cfg,py} files).
- Mark Python3.12 as supported in project.classifiers.
- Updated the
//run
script to use python3.
- Added
-
v0.9.19 (2024-03-03)
- Replaced the benchmarking data files that came from chromium.org with three files obtained from other datasets on GitHub. Since this repo is vendored into the chromium/src repo it was occasionally confusing people who thought the data was actually used for non-benchmarking purposes and thus updating it for whatever reason.
- No code changes.
-
v0.9.18 (2024-02-29)
- Add typing information to the module. This is kind of a big change, but there should be no functional differences.
-
v0.9.17 (2024-02-19)
- Move from
setup.py
topyproject.toml
. - No code changes (other than the version increasing).
- Move from
-
v0.9.16 (2024-02-19)
- Drop Python2 from
setup.py
- Add minimal packaging instructions to
//README.md
.
- Drop Python2 from
-
v0.9.15 (2024-02-19)
- Merge in Pull request #66 to include the tests and sample file in a source distribution.
-
v0.9.14 (2023-05-14)
- GitHub issue #63
Handle
+Infinity
as well as-Infinity
andInfinity
.
- GitHub issue #63
Handle
-
v0.9.13 (2023-03-16)
- GitHub PR #64 Remove a field from one of the JSON benchmark files to reduce confusion in Chromium.
- No code changes.
-
v0.9.12 (2023-01-02)
- Fix GitHub Actions config file to no longer test against Python 3.6 or 3.7. For now we will only test against an "oldest" release (3.8 in this case) and a "current" release (3.11 in this case).
-
v0.9.11 (2023-01-02)
- GitHub issue #60
Fixed minor Python2 compatibility issue by referring to
float("inf")
instead ofmath.inf
.
- GitHub issue #60
Fixed minor Python2 compatibility issue by referring to
-
v0.9.10 (2022-08-18)
- GitHub issue #58 Updated the //README.md to be clear that parsing arbitrary JS code may not work.
- Otherwise, no code changes.
-
v0.9.9 (2022-08-01)
- GitHub issue #57
Fixed serialization for objects that subclass
int
orfloat
: Previously we would use the objects str implementation, but that might result in an illegal JSON5 value if the object had customized str to return something illegal. Instead, we follow the lead of theJSON
module and callint.__repr__
orfloat.__repr__
directly. - While I was at it, I added tests for dumps(-inf) and dumps(nan)
when those were supposed to be disallowed by
allow_nan=False
.
- GitHub issue #57
Fixed serialization for objects that subclass
-
v0.9.8 (2022-05-08)
- GitHub issue #47 Fixed error reporting in some cases due to how parsing was handling nested rules in the grammar - previously the reported location for the error could be far away from the point where it actually happened.
-
v0.9.7 (2022-05-06)
- GitHub issue #52
Fixed behavior of
default
fn indump
anddumps
. Previously we didn't require the function to return a string, and so we could end up returning something that wasn't actually valid. This change now matches the behavior in thejson
module. Note: This is a potentially breaking change.
- GitHub issue #52
Fixed behavior of
-
v0.9.6 (2021-06-21)
- Bump development status classifier to 5 - Production/Stable, which the library feels like it is at this point. If I do end up significantly reworking things to speed it up and/or to add round-trip editing, that'll likely be a 2.0. If this version has no reported issues, I'll likely promote it to 1.0.
- Also bump the tested Python versions to 2.7, 3.8 and 3.9, though earlier Python3 versions will likely continue to work as well.
- GitHub issue #46 Fix incorrect serialization of custom subtypes
- Make it possible to run the tests if
hypothesis
isn't installed.
-
v0.9.5 (2020-05-26)
- Miscellaneous non-source cleanups in the repo, including setting up GitHub Actions for a CI system. No changes to the library from v0.9.4, other than updating the version.
-
v0.9.4 (2020-03-26)
- GitHub pull #38 Fix from [email protected] for dumps() crashing when passed an empty string as a key in an object.
-
v0.9.3 (2020-03-17)
- GitHub pull #35 Fix from pastelmind@ for dump() not passing the right args to dumps().
- Fix from [email protected] to remove the tests directory from the setup call, making the package a bit smaller.
-
v0.9.2 (2020-03-02)
- GitHub pull #34 Fix from roosephu@ for a badly formatted nested list.
-
v0.9.1 (2020-02-09)
- GitHub issue #33: Fix stray trailing comma when dumping an object with an invalid key.
-
v0.9.0 (2020-01-30)
- GitHub issue #29: Fix an issue where objects keys that started with a reserved word were incorrectly quoted.
- GitHub issue #30: Fix an issue where dumps() incorrectly thought a data structure was cyclic in some cases.
- GitHub issue #32:
Allow for non-string keys in dicts passed to
dump()
/dumps()
. Add anallow_duplicate_keys=False
to prevent possible ill-formed JSON that might result.
-
v0.8.5 (2019-07-04)
- GitHub issue #25: Add LICENSE and README.md to the dist.
- GitHub issue #26: Fix printing of empty arrays and objects with indentation, fix misreporting of the position on parse failures in some cases.
-
v0.8.4 (2019-06-11)
- Updated the version history, too.
-
v0.8.3 (2019-06-11)
- Tweaked the README, bumped the version, forgot to update the version history :).
-
v0.8.2 (2019-06-11)
- Actually bump the version properly, to 0.8.2.
-
v0.8.1 (2019-06-11)
- Fix bug in setup.py that messed up the description. Unfortunately, I forgot to bump the version for this, so this also identifies as 0.8.0.
-
v0.8.0 (2019-06-11)
- Add
allow_duplicate_keys=True
as a default argument tojson5.load()
/json5.loads()
. If you set the key toFalse
, duplicate keys in a single dict will be rejected. The default is set toTrue
for compatibility withjson.load()
, earlier versions of json5, and because it's simply not clear if people would want duplicate checking enabled by default.
- Add
-
v0.7 (2019-03-31)
- Changes dump()/dumps() to not quote object keys by default if they are
legal identifiers. Passing
quote_keys=True
will turn that off and always quote object keys. - Changes dump()/dumps() to insert trailing commas after the last item
in an array or an object if the object is printed across multiple lines
(i.e., if
indent
is not None). Passingtrailing_commas=False
will turn that off. - The
json5.tool
command line tool now supports the--indent
,--[no-]quote-keys
, and--[no-]trailing-commas
flags to allow for more control over the output, in addition to the existing--as-json
flag. - The
json5.tool
command line tool no longer supports reading from multiple files, you can now only read from a single file or from standard input. - The implementation no longer relies on the standard
json
module for anything. The output should still match the json module (except as noted above) and discrepancies should be reported as bugs.
- Changes dump()/dumps() to not quote object keys by default if they are
legal identifiers. Passing
-
v0.6.2 (2019-03-08)
- Fix GitHub issue #23 and pass through unrecognized escape sequences.
-
v0.6.1 (2018-05-22)
- Cleaned up a couple minor nits in the package.
-
v0.6.0 (2017-11-28)
- First implementation that attempted to implement 100% of the spec.
-
v0.5.0 (2017-09-04)
- First implementation that supported the full set of kwargs that
the
json
module supports.
- First implementation that supported the full set of kwargs that
the