|
| 1 | +r"""JSON (JavaScript Object Notation) <http://json.org> is a subset of |
| 2 | +JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data |
| 3 | +interchange format. |
| 4 | +
|
| 5 | +:mod:`json` exposes an API familiar to users of the standard library |
| 6 | +:mod:`marshal` and :mod:`pickle` modules. It is derived from a |
| 7 | +version of the externally maintained simplejson library. |
| 8 | +
|
| 9 | +Encoding basic Python object hierarchies:: |
| 10 | +
|
| 11 | + >>> import json |
| 12 | + >>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}]) |
| 13 | + '["foo", {"bar": ["baz", null, 1.0, 2]}]' |
| 14 | + >>> print(json.dumps("\"foo\bar")) |
| 15 | + "\"foo\bar" |
| 16 | + >>> print(json.dumps('\u1234')) |
| 17 | + "\u1234" |
| 18 | + >>> print(json.dumps('\\')) |
| 19 | + "\\" |
| 20 | + >>> print(json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)) |
| 21 | + {"a": 0, "b": 0, "c": 0} |
| 22 | + >>> from io import StringIO |
| 23 | + >>> io = StringIO() |
| 24 | + >>> json.dump(['streaming API'], io) |
| 25 | + >>> io.getvalue() |
| 26 | + '["streaming API"]' |
| 27 | +
|
| 28 | +Compact encoding:: |
| 29 | +
|
| 30 | + >>> import json |
| 31 | + >>> mydict = {'4': 5, '6': 7} |
| 32 | + >>> json.dumps([1,2,3,mydict], separators=(',', ':')) |
| 33 | + '[1,2,3,{"4":5,"6":7}]' |
| 34 | +
|
| 35 | +Pretty printing:: |
| 36 | +
|
| 37 | + >>> import json |
| 38 | + >>> print(json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)) |
| 39 | + { |
| 40 | + "4": 5, |
| 41 | + "6": 7 |
| 42 | + } |
| 43 | +
|
| 44 | +Decoding JSON:: |
| 45 | +
|
| 46 | + >>> import json |
| 47 | + >>> obj = ['foo', {'bar': ['baz', None, 1.0, 2]}] |
| 48 | + >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') == obj |
| 49 | + True |
| 50 | + >>> json.loads('"\\"foo\\bar"') == '"foo\x08ar' |
| 51 | + True |
| 52 | + >>> from io import StringIO |
| 53 | + >>> io = StringIO('["streaming API"]') |
| 54 | + >>> json.load(io)[0] == 'streaming API' |
| 55 | + True |
| 56 | +
|
| 57 | +Specializing JSON object decoding:: |
| 58 | +
|
| 59 | + >>> import json |
| 60 | + >>> def as_complex(dct): |
| 61 | + ... if '__complex__' in dct: |
| 62 | + ... return complex(dct['real'], dct['imag']) |
| 63 | + ... return dct |
| 64 | + ... |
| 65 | + >>> json.loads('{"__complex__": true, "real": 1, "imag": 2}', |
| 66 | + ... object_hook=as_complex) |
| 67 | + (1+2j) |
| 68 | + >>> from decimal import Decimal |
| 69 | + >>> json.loads('1.1', parse_float=Decimal) == Decimal('1.1') |
| 70 | + True |
| 71 | +
|
| 72 | +Specializing JSON object encoding:: |
| 73 | +
|
| 74 | + >>> import json |
| 75 | + >>> def encode_complex(obj): |
| 76 | + ... if isinstance(obj, complex): |
| 77 | + ... return [obj.real, obj.imag] |
| 78 | + ... raise TypeError(f'Object of type {obj.__class__.__name__} ' |
| 79 | + ... f'is not JSON serializable') |
| 80 | + ... |
| 81 | + >>> json.dumps(2 + 1j, default=encode_complex) |
| 82 | + '[2.0, 1.0]' |
| 83 | + >>> json.JSONEncoder(default=encode_complex).encode(2 + 1j) |
| 84 | + '[2.0, 1.0]' |
| 85 | + >>> ''.join(json.JSONEncoder(default=encode_complex).iterencode(2 + 1j)) |
| 86 | + '[2.0, 1.0]' |
| 87 | +
|
| 88 | +
|
| 89 | +Using json.tool from the shell to validate and pretty-print:: |
| 90 | +
|
| 91 | + $ echo '{"json":"obj"}' | python -m json.tool |
| 92 | + { |
| 93 | + "json": "obj" |
| 94 | + } |
| 95 | + $ echo '{ 1.2:3.4}' | python -m json.tool |
| 96 | + Expecting property name enclosed in double quotes: line 1 column 3 (char 2) |
| 97 | +""" |
| 98 | +__version__ = '2.0.9' |
| 99 | +__all__ = [ |
| 100 | + 'dump', 'dumps', 'load', 'loads', |
| 101 | + 'JSONDecoder', 'JSONDecodeError', 'JSONEncoder', |
| 102 | +] |
| 103 | + |
| 104 | +__author__ = 'Bob Ippolito <bob@redivi.com>' |
| 105 | + |
| 106 | +from .decoder import JSONDecoder, JSONDecodeError |
| 107 | +from .encoder import JSONEncoder |
| 108 | +import codecs |
| 109 | + |
| 110 | +_default_encoder = JSONEncoder( |
| 111 | + skipkeys=False, |
| 112 | + ensure_ascii=True, |
| 113 | + check_circular=True, |
| 114 | + allow_nan=True, |
| 115 | + indent=None, |
| 116 | + separators=None, |
| 117 | + default=None, |
| 118 | +) |
| 119 | + |
| 120 | +def dump(obj, fp, *, skipkeys=False, ensure_ascii=True, check_circular=True, |
| 121 | + allow_nan=True, cls=None, indent=None, separators=None, |
| 122 | + default=None, sort_keys=False, **kw): |
| 123 | + """Serialize ``obj`` as a JSON formatted stream to ``fp`` (a |
| 124 | + ``.write()``-supporting file-like object). |
| 125 | +
|
| 126 | + If ``skipkeys`` is true then ``dict`` keys that are not basic types |
| 127 | + (``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped |
| 128 | + instead of raising a ``TypeError``. |
| 129 | +
|
| 130 | + If ``ensure_ascii`` is false, then the strings written to ``fp`` can |
| 131 | + contain non-ASCII characters if they appear in strings contained in |
| 132 | + ``obj``. Otherwise, all such characters are escaped in JSON strings. |
| 133 | +
|
| 134 | + If ``check_circular`` is false, then the circular reference check |
| 135 | + for container types will be skipped and a circular reference will |
| 136 | + result in an ``OverflowError`` (or worse). |
| 137 | +
|
| 138 | + If ``allow_nan`` is false, then it will be a ``ValueError`` to |
| 139 | + serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) |
| 140 | + in strict compliance of the JSON specification, instead of using the |
| 141 | + JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). |
| 142 | +
|
| 143 | + If ``indent`` is a non-negative integer, then JSON array elements and |
| 144 | + object members will be pretty-printed with that indent level. An indent |
| 145 | + level of 0 will only insert newlines. ``None`` is the most compact |
| 146 | + representation. |
| 147 | +
|
| 148 | + If specified, ``separators`` should be an ``(item_separator, key_separator)`` |
| 149 | + tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and |
| 150 | + ``(',', ': ')`` otherwise. To get the most compact JSON representation, |
| 151 | + you should specify ``(',', ':')`` to eliminate whitespace. |
| 152 | +
|
| 153 | + ``default(obj)`` is a function that should return a serializable version |
| 154 | + of obj or raise TypeError. The default simply raises TypeError. |
| 155 | +
|
| 156 | + If *sort_keys* is true (default: ``False``), then the output of |
| 157 | + dictionaries will be sorted by key. |
| 158 | +
|
| 159 | + To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the |
| 160 | + ``.default()`` method to serialize additional types), specify it with |
| 161 | + the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. |
| 162 | +
|
| 163 | + """ |
| 164 | + # cached encoder |
| 165 | + if (not skipkeys and ensure_ascii and |
| 166 | + check_circular and allow_nan and |
| 167 | + cls is None and indent is None and separators is None and |
| 168 | + default is None and not sort_keys and not kw): |
| 169 | + iterable = _default_encoder.iterencode(obj) |
| 170 | + else: |
| 171 | + if cls is None: |
| 172 | + cls = JSONEncoder |
| 173 | + iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii, |
| 174 | + check_circular=check_circular, allow_nan=allow_nan, indent=indent, |
| 175 | + separators=separators, |
| 176 | + default=default, sort_keys=sort_keys, **kw).iterencode(obj) |
| 177 | + # could accelerate with writelines in some versions of Python, at |
| 178 | + # a debuggability cost |
| 179 | + for chunk in iterable: |
| 180 | + fp.write(chunk) |
| 181 | + |
| 182 | + |
| 183 | +def dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, |
| 184 | + allow_nan=True, cls=None, indent=None, separators=None, |
| 185 | + default=None, sort_keys=False, **kw): |
| 186 | + """Serialize ``obj`` to a JSON formatted ``str``. |
| 187 | +
|
| 188 | + If ``skipkeys`` is true then ``dict`` keys that are not basic types |
| 189 | + (``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped |
| 190 | + instead of raising a ``TypeError``. |
| 191 | +
|
| 192 | + If ``ensure_ascii`` is false, then the return value can contain non-ASCII |
| 193 | + characters if they appear in strings contained in ``obj``. Otherwise, all |
| 194 | + such characters are escaped in JSON strings. |
| 195 | +
|
| 196 | + If ``check_circular`` is false, then the circular reference check |
| 197 | + for container types will be skipped and a circular reference will |
| 198 | + result in an ``OverflowError`` (or worse). |
| 199 | +
|
| 200 | + If ``allow_nan`` is false, then it will be a ``ValueError`` to |
| 201 | + serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in |
| 202 | + strict compliance of the JSON specification, instead of using the |
| 203 | + JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). |
| 204 | +
|
| 205 | + If ``indent`` is a non-negative integer, then JSON array elements and |
| 206 | + object members will be pretty-printed with that indent level. An indent |
| 207 | + level of 0 will only insert newlines. ``None`` is the most compact |
| 208 | + representation. |
| 209 | +
|
| 210 | + If specified, ``separators`` should be an ``(item_separator, key_separator)`` |
| 211 | + tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and |
| 212 | + ``(',', ': ')`` otherwise. To get the most compact JSON representation, |
| 213 | + you should specify ``(',', ':')`` to eliminate whitespace. |
| 214 | +
|
| 215 | + ``default(obj)`` is a function that should return a serializable version |
| 216 | + of obj or raise TypeError. The default simply raises TypeError. |
| 217 | +
|
| 218 | + If *sort_keys* is true (default: ``False``), then the output of |
| 219 | + dictionaries will be sorted by key. |
| 220 | +
|
| 221 | + To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the |
| 222 | + ``.default()`` method to serialize additional types), specify it with |
| 223 | + the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. |
| 224 | +
|
| 225 | + """ |
| 226 | + # cached encoder |
| 227 | + if (not skipkeys and ensure_ascii and |
| 228 | + check_circular and allow_nan and |
| 229 | + cls is None and indent is None and separators is None and |
| 230 | + default is None and not sort_keys and not kw): |
| 231 | + return _default_encoder.encode(obj) |
| 232 | + if cls is None: |
| 233 | + cls = JSONEncoder |
| 234 | + return cls( |
| 235 | + skipkeys=skipkeys, ensure_ascii=ensure_ascii, |
| 236 | + check_circular=check_circular, allow_nan=allow_nan, indent=indent, |
| 237 | + separators=separators, default=default, sort_keys=sort_keys, |
| 238 | + **kw).encode(obj) |
| 239 | + |
| 240 | + |
| 241 | +_default_decoder = JSONDecoder(object_hook=None, object_pairs_hook=None) |
| 242 | + |
| 243 | + |
| 244 | +def detect_encoding(b): |
| 245 | + bstartswith = b.startswith |
| 246 | + if bstartswith((codecs.BOM_UTF32_BE, codecs.BOM_UTF32_LE)): |
| 247 | + return 'utf-32' |
| 248 | + if bstartswith((codecs.BOM_UTF16_BE, codecs.BOM_UTF16_LE)): |
| 249 | + return 'utf-16' |
| 250 | + if bstartswith(codecs.BOM_UTF8): |
| 251 | + return 'utf-8-sig' |
| 252 | + |
| 253 | + if len(b) >= 4: |
| 254 | + if not b[0]: |
| 255 | + # 00 00 -- -- - utf-32-be |
| 256 | + # 00 XX -- -- - utf-16-be |
| 257 | + return 'utf-16-be' if b[1] else 'utf-32-be' |
| 258 | + if not b[1]: |
| 259 | + # XX 00 00 00 - utf-32-le |
| 260 | + # XX 00 00 XX - utf-16-le |
| 261 | + # XX 00 XX -- - utf-16-le |
| 262 | + return 'utf-16-le' if b[2] or b[3] else 'utf-32-le' |
| 263 | + elif len(b) == 2: |
| 264 | + if not b[0]: |
| 265 | + # 00 XX - utf-16-be |
| 266 | + return 'utf-16-be' |
| 267 | + if not b[1]: |
| 268 | + # XX 00 - utf-16-le |
| 269 | + return 'utf-16-le' |
| 270 | + # default |
| 271 | + return 'utf-8' |
| 272 | + |
| 273 | + |
| 274 | +def load(fp, *, cls=None, object_hook=None, parse_float=None, |
| 275 | + parse_int=None, parse_constant=None, object_pairs_hook=None, **kw): |
| 276 | + """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing |
| 277 | + a JSON document) to a Python object. |
| 278 | +
|
| 279 | + ``object_hook`` is an optional function that will be called with the |
| 280 | + result of any object literal decode (a ``dict``). The return value of |
| 281 | + ``object_hook`` will be used instead of the ``dict``. This feature |
| 282 | + can be used to implement custom decoders (e.g. JSON-RPC class hinting). |
| 283 | +
|
| 284 | + ``object_pairs_hook`` is an optional function that will be called with the |
| 285 | + result of any object literal decoded with an ordered list of pairs. The |
| 286 | + return value of ``object_pairs_hook`` will be used instead of the ``dict``. |
| 287 | + This feature can be used to implement custom decoders. If ``object_hook`` |
| 288 | + is also defined, the ``object_pairs_hook`` takes priority. |
| 289 | +
|
| 290 | + To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` |
| 291 | + kwarg; otherwise ``JSONDecoder`` is used. |
| 292 | + """ |
| 293 | + return loads(fp.read(), |
| 294 | + cls=cls, object_hook=object_hook, |
| 295 | + parse_float=parse_float, parse_int=parse_int, |
| 296 | + parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw) |
| 297 | + |
| 298 | + |
| 299 | +def loads(s, *, cls=None, object_hook=None, parse_float=None, |
| 300 | + parse_int=None, parse_constant=None, object_pairs_hook=None, **kw): |
| 301 | + """Deserialize ``s`` (a ``str``, ``bytes`` or ``bytearray`` instance |
| 302 | + containing a JSON document) to a Python object. |
| 303 | +
|
| 304 | + ``object_hook`` is an optional function that will be called with the |
| 305 | + result of any object literal decode (a ``dict``). The return value of |
| 306 | + ``object_hook`` will be used instead of the ``dict``. This feature |
| 307 | + can be used to implement custom decoders (e.g. JSON-RPC class hinting). |
| 308 | +
|
| 309 | + ``object_pairs_hook`` is an optional function that will be called with the |
| 310 | + result of any object literal decoded with an ordered list of pairs. The |
| 311 | + return value of ``object_pairs_hook`` will be used instead of the ``dict``. |
| 312 | + This feature can be used to implement custom decoders. If ``object_hook`` |
| 313 | + is also defined, the ``object_pairs_hook`` takes priority. |
| 314 | +
|
| 315 | + ``parse_float``, if specified, will be called with the string |
| 316 | + of every JSON float to be decoded. By default this is equivalent to |
| 317 | + float(num_str). This can be used to use another datatype or parser |
| 318 | + for JSON floats (e.g. decimal.Decimal). |
| 319 | +
|
| 320 | + ``parse_int``, if specified, will be called with the string |
| 321 | + of every JSON int to be decoded. By default this is equivalent to |
| 322 | + int(num_str). This can be used to use another datatype or parser |
| 323 | + for JSON integers (e.g. float). |
| 324 | +
|
| 325 | + ``parse_constant``, if specified, will be called with one of the |
| 326 | + following strings: -Infinity, Infinity, NaN. |
| 327 | + This can be used to raise an exception if invalid JSON numbers |
| 328 | + are encountered. |
| 329 | +
|
| 330 | + To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` |
| 331 | + kwarg; otherwise ``JSONDecoder`` is used. |
| 332 | +
|
| 333 | + The ``encoding`` argument is ignored and deprecated since Python 3.1. |
| 334 | + """ |
| 335 | + if isinstance(s, str): |
| 336 | + if s.startswith('\ufeff'): |
| 337 | + raise JSONDecodeError("Unexpected UTF-8 BOM (decode using utf-8-sig)", |
| 338 | + s, 0) |
| 339 | + else: |
| 340 | + if not isinstance(s, (bytes, bytearray)): |
| 341 | + raise TypeError(f'the JSON object must be str, bytes or bytearray, ' |
| 342 | + f'not {s.__class__.__name__}') |
| 343 | + s = s.decode(detect_encoding(s), 'surrogatepass') |
| 344 | + |
| 345 | + if "encoding" in kw: |
| 346 | + import warnings |
| 347 | + warnings.warn( |
| 348 | + "'encoding' is ignored and deprecated. It will be removed in Python 3.9", |
| 349 | + DeprecationWarning, |
| 350 | + stacklevel=2 |
| 351 | + ) |
| 352 | + del kw['encoding'] |
| 353 | + |
| 354 | + if (cls is None and object_hook is None and |
| 355 | + parse_int is None and parse_float is None and |
| 356 | + parse_constant is None and object_pairs_hook is None and not kw): |
| 357 | + return _default_decoder.decode(s) |
| 358 | + if cls is None: |
| 359 | + cls = JSONDecoder |
| 360 | + if object_hook is not None: |
| 361 | + kw['object_hook'] = object_hook |
| 362 | + if object_pairs_hook is not None: |
| 363 | + kw['object_pairs_hook'] = object_pairs_hook |
| 364 | + if parse_float is not None: |
| 365 | + kw['parse_float'] = parse_float |
| 366 | + if parse_int is not None: |
| 367 | + kw['parse_int'] = parse_int |
| 368 | + if parse_constant is not None: |
| 369 | + kw['parse_constant'] = parse_constant |
| 370 | + return cls(**kw).decode(s) |
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