"""Implementation of JSONEncoder
from _json import encode_basestring_ascii as c_encode_basestring_ascii
c_encode_basestring_ascii = None
from _json import encode_basestring as c_encode_basestring
c_encode_basestring = None
from _json import make_encoder as c_make_encoder
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.setdefault(chr(i), '\\u{0:04x}'.format(i))
#ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
def py_encode_basestring(s):
"""Return a JSON representation of a Python string
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
return '\\u{0:04x}'.format(n)
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:
+-------------------+---------------+
+===================+===============+
+-------------------+---------------+
+-------------------+---------------+
+-------------------+---------------+
+-------------------+---------------+
+-------------------+---------------+
+-------------------+---------------+
+-------------------+---------------+
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``).
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 OverflowError).
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.ensure_ascii = ensure_ascii
self.check_circular = check_circular
self.allow_nan = allow_nan
self.sort_keys = sort_keys
if separators is not None:
self.item_separator, self.key_separator = separators
self.item_separator = ','
"""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::
# Let the base class default method raise the TypeError
return JSONEncoder.default(self, o)
raise TypeError("Object of type '%s' is not JSON serializable" %
"""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.
return encode_basestring_ascii(o)
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)):
def iterencode(self, o, _one_shot=False):
"""Encode the given object and yield each string
representation as available.
for chunk in JSONEncoder().iterencode(bigobject):
_encoder = encode_basestring_ascii
_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
"Out of range float values are not JSON compliant: " +
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)
_iterencode = _make_iterencode(
markers, self.default, _encoder, self.indent, floatstr,
self.key_separator, self.item_separator, self.sort_keys,
self.skipkeys, _one_shot)
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
if _indent is not None and not isinstance(_indent, str):
def _iterencode_list(lst, _current_indent_level):
raise ValueError("Circular reference detected")
_current_indent_level += 1
newline_indent = '\n' + _indent * _current_indent_level
separator = _item_separator + newline_indent
separator = _item_separator
if isinstance(value, str):
yield buf + _encoder(value)
elif isinstance(value, int):
# Subclasses of int/float may override __str__, 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)
if isinstance(value, (list, tuple)):
chunks = _iterencode_list(value, _current_indent_level)
elif isinstance(value, dict):
chunks = _iterencode_dict(value, _current_indent_level)
chunks = _iterencode(value, _current_indent_level)
if newline_indent is not None:
_current_indent_level -= 1
yield '\n' + _indent * _current_indent_level
def _iterencode_dict(dct, _current_indent_level):
raise ValueError("Circular reference detected")
_current_indent_level += 1
newline_indent = '\n' + _indent * _current_indent_level
item_separator = _item_separator + newline_indent
item_separator = _item_separator
items = sorted(dct.items(), key=lambda kv: kv[0])
# 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
elif isinstance(key, int):
# see comment for int/float in _make_iterencode
raise TypeError("key " + repr(key) + " is not a string")
if isinstance(value, str):
elif isinstance(value, int):
# see comment for int/float in _make_iterencode
elif isinstance(value, float):
# see comment for int/float in _make_iterencode
if isinstance(value, (list, tuple)):
chunks = _iterencode_list(value, _current_indent_level)
elif isinstance(value, dict):
chunks = _iterencode_dict(value, _current_indent_level)
chunks = _iterencode(value, _current_indent_level)
if newline_indent is not None:
_current_indent_level -= 1
yield '\n' + _indent * _current_indent_level
def _iterencode(o, _current_indent_level):
# see comment for int/float in _make_iterencode
elif isinstance(o, float):
# see comment for int/float in _make_iterencode
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)
raise ValueError("Circular reference detected")
yield from _iterencode(o, _current_indent_level)