#!/usr/bin/env python # -*- coding: utf-8 -*- """Add JavaScript or Python style comments in JSON. commentjson (Comment JSON) is a Python package that helps you create JSON files with Python and JavaScript style inline comments. Its API is very similar to the Python standard library’s json module. """ from __future__ import print_function from __future__ import division from __future__ import absolute_import from __future__ import unicode_literals import codecs import traceback try: import json except ImportError: # If python version is 2.5 or less, use simplejson import simplejson as json import lark from lark import Lark from lark.reconstruct import Reconstructor parser = Lark(''' ?start: value ?value: object | array | string | SIGNED_NUMBER -> number | "true" -> true | "false" -> false | "null" -> null array : "[" [value ("," value)*] "]" object : "{" [pair ("," pair)*] "}" pair : string ":" value string : ESCAPED_STRING COMMENT: /(#|\/\/)[^\\n]*/ %import common.ESCAPED_STRING %import common.SIGNED_NUMBER %import common.WS %ignore WS %ignore COMMENT ''', maybe_placeholders=False) serializer = Reconstructor(parser) def detect_encoding(b): ''' Taken from `json` package in CPython 3.7. Source can be found at https://bit.ly/2OHqCIK. ''' bstartswith = b.startswith if bstartswith((codecs.BOM_UTF32_BE, codecs.BOM_UTF32_LE)): return 'utf-32' if bstartswith((codecs.BOM_UTF16_BE, codecs.BOM_UTF16_LE)): return 'utf-16' if bstartswith(codecs.BOM_UTF8): return 'utf-8-sig' if len(b) >= 4: if not b[0]: # 00 00 -- -- - utf-32-be # 00 XX -- -- - utf-16-be return 'utf-16-be' if b[1] else 'utf-32-be' if not b[1]: # XX 00 00 00 - utf-32-le # XX 00 00 XX - utf-16-le # XX 00 XX -- - utf-16-le return 'utf-16-le' if b[2] or b[3] else 'utf-32-le' elif len(b) == 2: if not b[0]: # 00 XX - utf-16-be return 'utf-16-be' if not b[1]: # XX 00 - utf-16-le return 'utf-16-le' # default return 'utf-8' class BaseException(Exception): ''' Base exception to be implemented and raised while handling exceptions raised by libraries used in `commentjson`. Sets message of self in a way that it clearly calls out that the exception was raised by another library, along with the entire stacktrace of the exception raised by the other library. ''' def __init__(self, exc): if self.library is None: raise NotImplementedError( 'Value of library must be set in the ' 'inherited exception class.') tb = traceback.format_exc() tb = '\n'.join(' ' * 4 + line_ for line_ in tb.split('\n')) error = None try: error = exc.msg except AttributeError: try: error = exc.message except AttributeError: error = str(exc) self.message = '\n'.join([ 'JSON Library Exception\n', ('Exception thrown by library (%s): ' '\033[4;37m%s\033[0m\n' % (self.library, error)), '%s' % tb, ]) Exception.__init__(self, self.message) class ParserException(BaseException): '''Exception raised when the `lark` raises an exception i.e. the exception is not caused by `commentjson` and caused by the use of `lark` in `commentjson`. ''' library = 'lark' class JSONLibraryException(BaseException): '''Exception raised when the `json` raises an exception i.e. the exception is not caused by `commentjson` and caused by the use of `json` in `commentjson`. .. note:: As of now, ``commentjson`` supports only standard library's ``json`` module. It might start supporting other widely-used contributed JSON libraries in the future. ''' library = 'json' def loads(text, *args, **kwargs): ''' Deserialize `text` (a `str` or `unicode` instance containing a JSON document with Python or JavaScript like comments) to a Python object. :param text: serialized JSON string with or without comments. :param kwargs: all the arguments that `json.loads `_ accepts. :returns: dict or list. ''' if isinstance(text, (bytes, bytearray)): text = text.decode(detect_encoding(text), 'surrogatepass') try: parsed = parser.parse(text) final_text = serializer.reconstruct(parsed) except lark.exceptions.UnexpectedCharacters: raise ValueError('Unable to parse text', text) return json.loads(final_text, *args, **kwargs) def dumps(obj, **kwargs): ''' Serialize `obj` to a JSON formatted `str`. Accepts the same arguments as `json` module in stdlib. :param obj: a JSON serializable Python object. :param kwargs: all the arguments that `json.dumps `_ accepts. :raises: commentjson.JSONLibraryException :returns str: serialized string. ''' return json.dumps(obj, **kwargs) def load(fp, **kwargs): ''' Deserialize `fp` (a `.read()`-supporting file-like object containing a JSON document with Python or JavaScript like comments) to a Python object. :param fp: a `.read()`-supporting file-like object containing a JSON document with or without comments. :param kwargs: all the arguments that `json.load `_ accepts. :raises: commentjson.JSONLibraryException :returns: dict or list. ''' try: return loads(fp.read(), **kwargs) except Exception as e: raise JSONLibraryException(e) def dump(obj, fp, **kwargs): ''' Serialize `obj` as a JSON formatted stream to `fp` (a `.write()`-supporting file-like object). Accepts the same arguments as `json` module in stdlib. :param obj: a JSON serializable Python object. :param fp: a `.read()`-supporting file-like object containing a JSON document with or without comments. :param kwargs: all the arguments that `json.dump `_ accepts. :raises: commentjson.JSONLibraryException ''' try: json.dump(obj, fp, **kwargs) except Exception as e: raise JSONLibraryException(e)