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- """Implementation of JSONEncoder
- """
- import re
- try:
- from _json import encode_basestring_ascii as c_encode_basestring_ascii
- except ImportError:
- c_encode_basestring_ascii = None
- try:
- from _json import encode_basestring as c_encode_basestring
- except ImportError:
- c_encode_basestring = None
- try:
- from _json import make_encoder as c_make_encoder
- except ImportError:
- c_make_encoder = None
- ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
- ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
- HAS_UTF8 = re.compile(b'[\x80-\xff]')
- ESCAPE_DCT = {
- '\\': '\\\\',
- '"': '\\"',
- '\b': '\\b',
- '\f': '\\f',
- '\n': '\\n',
- '\r': '\\r',
- '\t': '\\t',
- }
- for i in range(0x20):
- ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))
- #ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
- INFINITY = float('inf')
- def py_encode_basestring(s):
- """Return a JSON representation of a Python string
- """
- def replace(match):
- return ESCAPE_DCT[match.group(0)]
- return '"' + ESCAPE.sub(replace, s) + '"'
- encode_basestring = (c_encode_basestring or py_encode_basestring)
- def py_encode_basestring_ascii(s):
- """Return an ASCII-only JSON representation of a Python string
- """
- def replace(match):
- s = match.group(0)
- try:
- return ESCAPE_DCT[s]
- except KeyError:
- n = ord(s)
- if n < 0x10000:
- return '\\u{0:04x}'.format(n)
- #return '\\u%04x' % (n,)
- else:
- # surrogate pair
- n -= 0x10000
- s1 = 0xd800 | ((n >> 10) & 0x3ff)
- s2 = 0xdc00 | (n & 0x3ff)
- return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)
- return '"' + ESCAPE_ASCII.sub(replace, s) + '"'
- encode_basestring_ascii = (
- c_encode_basestring_ascii or py_encode_basestring_ascii)
- class JSONEncoder(object):
- """Extensible JSON <http://json.org> encoder for Python data structures.
- Supports the following objects and types by default:
- +-------------------+---------------+
- | Python | JSON |
- +===================+===============+
- | dict | object |
- +-------------------+---------------+
- | list, tuple | array |
- +-------------------+---------------+
- | str | string |
- +-------------------+---------------+
- | int, float | number |
- +-------------------+---------------+
- | True | true |
- +-------------------+---------------+
- | False | false |
- +-------------------+---------------+
- | None | null |
- +-------------------+---------------+
- To extend this to recognize other objects, subclass and implement a
- ``.default()`` method with another method that returns a serializable
- object for ``o`` if possible, otherwise it should call the superclass
- implementation (to raise ``TypeError``).
- """
- item_separator = ', '
- key_separator = ': '
- def __init__(self, *, skipkeys=False, ensure_ascii=True,
- check_circular=True, allow_nan=True, sort_keys=False,
- indent=None, separators=None, default=None):
- """Constructor for JSONEncoder, with sensible defaults.
- If skipkeys is false, then it is a TypeError to attempt
- encoding of keys that are not str, int, float or None. If
- skipkeys is True, such items are simply skipped.
- If ensure_ascii is true, the output is guaranteed to be str
- objects with all incoming non-ASCII characters escaped. If
- ensure_ascii is false, the output can contain non-ASCII characters.
- If check_circular is true, then lists, dicts, and custom encoded
- objects will be checked for circular references during encoding to
- prevent an infinite recursion (which would cause an RecursionError).
- Otherwise, no such check takes place.
- If allow_nan is true, then NaN, Infinity, and -Infinity will be
- encoded as such. This behavior is not JSON specification compliant,
- but is consistent with most JavaScript based encoders and decoders.
- Otherwise, it will be a ValueError to encode such floats.
- If sort_keys is true, then the output of dictionaries will be
- sorted by key; this is useful for regression tests to ensure
- that JSON serializations can be compared on a day-to-day basis.
- If indent is a non-negative integer, then JSON array
- elements and object members will be pretty-printed with that
- indent level. An indent level of 0 will only insert newlines.
- None is the most compact representation.
- If specified, separators should be an (item_separator, key_separator)
- tuple. The default is (', ', ': ') if *indent* is ``None`` and
- (',', ': ') otherwise. To get the most compact JSON representation,
- you should specify (',', ':') to eliminate whitespace.
- If specified, default is a function that gets called for objects
- that can't otherwise be serialized. It should return a JSON encodable
- version of the object or raise a ``TypeError``.
- """
- self.skipkeys = skipkeys
- self.ensure_ascii = ensure_ascii
- self.check_circular = check_circular
- self.allow_nan = allow_nan
- self.sort_keys = sort_keys
- self.indent = indent
- if separators is not None:
- self.item_separator, self.key_separator = separators
- elif indent is not None:
- self.item_separator = ','
- if default is not None:
- self.default = default
- def default(self, o):
- """Implement this method in a subclass such that it returns
- a serializable object for ``o``, or calls the base implementation
- (to raise a ``TypeError``).
- For example, to support arbitrary iterators, you could
- implement default like this::
- def default(self, o):
- try:
- iterable = iter(o)
- except TypeError:
- pass
- else:
- return list(iterable)
- # Let the base class default method raise the TypeError
- return JSONEncoder.default(self, o)
- """
- raise TypeError(f'Object of type {o.__class__.__name__} '
- f'is not JSON serializable')
- def encode(self, o):
- """Return a JSON string representation of a Python data structure.
- >>> from json.encoder import JSONEncoder
- >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
- '{"foo": ["bar", "baz"]}'
- """
- # This is for extremely simple cases and benchmarks.
- if isinstance(o, str):
- if self.ensure_ascii:
- return encode_basestring_ascii(o)
- else:
- return encode_basestring(o)
- # This doesn't pass the iterator directly to ''.join() because the
- # exceptions aren't as detailed. The list call should be roughly
- # equivalent to the PySequence_Fast that ''.join() would do.
- chunks = self.iterencode(o, _one_shot=True)
- if not isinstance(chunks, (list, tuple)):
- chunks = list(chunks)
- return ''.join(chunks)
- def iterencode(self, o, _one_shot=False):
- """Encode the given object and yield each string
- representation as available.
- For example::
- for chunk in JSONEncoder().iterencode(bigobject):
- mysocket.write(chunk)
- """
- if self.check_circular:
- markers = {}
- else:
- markers = None
- if self.ensure_ascii:
- _encoder = encode_basestring_ascii
- else:
- _encoder = encode_basestring
- def floatstr(o, allow_nan=self.allow_nan,
- _repr=float.__repr__, _inf=INFINITY, _neginf=-INFINITY):
- # Check for specials. Note that this type of test is processor
- # and/or platform-specific, so do tests which don't depend on the
- # internals.
- if o != o:
- text = 'NaN'
- elif o == _inf:
- text = 'Infinity'
- elif o == _neginf:
- text = '-Infinity'
- else:
- return _repr(o)
- if not allow_nan:
- raise ValueError(
- "Out of range float values are not JSON compliant: " +
- repr(o))
- return text
- if (_one_shot and c_make_encoder is not None
- and self.indent is None):
- _iterencode = c_make_encoder(
- markers, self.default, _encoder, self.indent,
- self.key_separator, self.item_separator, self.sort_keys,
- self.skipkeys, self.allow_nan)
- else:
- _iterencode = _make_iterencode(
- markers, self.default, _encoder, self.indent, floatstr,
- self.key_separator, self.item_separator, self.sort_keys,
- self.skipkeys, _one_shot)
- return _iterencode(o, 0)
- def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
- _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
- ## HACK: hand-optimized bytecode; turn globals into locals
- ValueError=ValueError,
- dict=dict,
- float=float,
- id=id,
- int=int,
- isinstance=isinstance,
- list=list,
- str=str,
- tuple=tuple,
- _intstr=int.__repr__,
- ):
- if _indent is not None and not isinstance(_indent, str):
- _indent = ' ' * _indent
- def _iterencode_list(lst, _current_indent_level):
- if not lst:
- yield '[]'
- return
- if markers is not None:
- markerid = id(lst)
- if markerid in markers:
- raise ValueError("Circular reference detected")
- markers[markerid] = lst
- buf = '['
- if _indent is not None:
- _current_indent_level += 1
- newline_indent = '\n' + _indent * _current_indent_level
- separator = _item_separator + newline_indent
- buf += newline_indent
- else:
- newline_indent = None
- separator = _item_separator
- first = True
- for value in lst:
- if first:
- first = False
- else:
- buf = separator
- if isinstance(value, str):
- yield buf + _encoder(value)
- elif value is None:
- yield buf + 'null'
- elif value is True:
- yield buf + 'true'
- elif value is False:
- yield buf + 'false'
- elif isinstance(value, int):
- # Subclasses of int/float may override __repr__, but we still
- # want to encode them as integers/floats in JSON. One example
- # within the standard library is IntEnum.
- yield buf + _intstr(value)
- elif isinstance(value, float):
- # see comment above for int
- yield buf + _floatstr(value)
- else:
- yield buf
- if isinstance(value, (list, tuple)):
- chunks = _iterencode_list(value, _current_indent_level)
- elif isinstance(value, dict):
- chunks = _iterencode_dict(value, _current_indent_level)
- else:
- chunks = _iterencode(value, _current_indent_level)
- yield from chunks
- if newline_indent is not None:
- _current_indent_level -= 1
- yield '\n' + _indent * _current_indent_level
- yield ']'
- if markers is not None:
- del markers[markerid]
- def _iterencode_dict(dct, _current_indent_level):
- if not dct:
- yield '{}'
- return
- if markers is not None:
- markerid = id(dct)
- if markerid in markers:
- raise ValueError("Circular reference detected")
- markers[markerid] = dct
- yield '{'
- if _indent is not None:
- _current_indent_level += 1
- newline_indent = '\n' + _indent * _current_indent_level
- item_separator = _item_separator + newline_indent
- yield newline_indent
- else:
- newline_indent = None
- item_separator = _item_separator
- first = True
- if _sort_keys:
- items = sorted(dct.items())
- else:
- items = dct.items()
- for key, value in items:
- if isinstance(key, str):
- pass
- # JavaScript is weakly typed for these, so it makes sense to
- # also allow them. Many encoders seem to do something like this.
- elif isinstance(key, float):
- # see comment for int/float in _make_iterencode
- key = _floatstr(key)
- elif key is True:
- key = 'true'
- elif key is False:
- key = 'false'
- elif key is None:
- key = 'null'
- elif isinstance(key, int):
- # see comment for int/float in _make_iterencode
- key = _intstr(key)
- elif _skipkeys:
- continue
- else:
- raise TypeError(f'keys must be str, int, float, bool or None, '
- f'not {key.__class__.__name__}')
- if first:
- first = False
- else:
- yield item_separator
- yield _encoder(key)
- yield _key_separator
- if isinstance(value, str):
- yield _encoder(value)
- elif value is None:
- yield 'null'
- elif value is True:
- yield 'true'
- elif value is False:
- yield 'false'
- elif isinstance(value, int):
- # see comment for int/float in _make_iterencode
- yield _intstr(value)
- elif isinstance(value, float):
- # see comment for int/float in _make_iterencode
- yield _floatstr(value)
- else:
- if isinstance(value, (list, tuple)):
- chunks = _iterencode_list(value, _current_indent_level)
- elif isinstance(value, dict):
- chunks = _iterencode_dict(value, _current_indent_level)
- else:
- chunks = _iterencode(value, _current_indent_level)
- yield from chunks
- if newline_indent is not None:
- _current_indent_level -= 1
- yield '\n' + _indent * _current_indent_level
- yield '}'
- if markers is not None:
- del markers[markerid]
- def _iterencode(o, _current_indent_level):
- if isinstance(o, str):
- yield _encoder(o)
- elif o is None:
- yield 'null'
- elif o is True:
- yield 'true'
- elif o is False:
- yield 'false'
- elif isinstance(o, int):
- # see comment for int/float in _make_iterencode
- yield _intstr(o)
- elif isinstance(o, float):
- # see comment for int/float in _make_iterencode
- yield _floatstr(o)
- elif isinstance(o, (list, tuple)):
- yield from _iterencode_list(o, _current_indent_level)
- elif isinstance(o, dict):
- yield from _iterencode_dict(o, _current_indent_level)
- else:
- if markers is not None:
- markerid = id(o)
- if markerid in markers:
- raise ValueError("Circular reference detected")
- markers[markerid] = o
- o = _default(o)
- yield from _iterencode(o, _current_indent_level)
- if markers is not None:
- del markers[markerid]
- return _iterencode
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