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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 <https://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 | |