Package django :: Package utils :: Package simplejson
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Source Code for Package django.utils.simplejson

  1  r""" 
  2  A simple, fast, extensible JSON encoder and decoder 
  3   
  4  JSON (JavaScript Object Notation) <http://json.org> is a subset of 
  5  JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data 
  6  interchange format. 
  7   
  8  simplejson exposes an API familiar to uses of the standard library 
  9  marshal and pickle modules. 
 10   
 11  Encoding basic Python object hierarchies:: 
 12       
 13      >>> import simplejson 
 14      >>> simplejson.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}]) 
 15      '["foo", {"bar": ["baz", null, 1.0, 2]}]' 
 16      >>> print simplejson.dumps("\"foo\bar") 
 17      "\"foo\bar" 
 18      >>> print simplejson.dumps(u'\u1234') 
 19      "\u1234" 
 20      >>> print simplejson.dumps('\\') 
 21      "\\" 
 22      >>> print simplejson.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True) 
 23      {"a": 0, "b": 0, "c": 0} 
 24      >>> from StringIO import StringIO 
 25      >>> io = StringIO() 
 26      >>> simplejson.dump(['streaming API'], io) 
 27      >>> io.getvalue() 
 28      '["streaming API"]' 
 29   
 30  Compact encoding:: 
 31   
 32      >>> import simplejson 
 33      >>> simplejson.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':')) 
 34      '[1,2,3,{"4":5,"6":7}]' 
 35   
 36  Pretty printing:: 
 37   
 38      >>> import simplejson 
 39      >>> print simplejson.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4) 
 40      { 
 41          "4": 5,  
 42          "6": 7 
 43      } 
 44   
 45  Decoding JSON:: 
 46       
 47      >>> import simplejson 
 48      >>> simplejson.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') 
 49      [u'foo', {u'bar': [u'baz', None, 1.0, 2]}] 
 50      >>> simplejson.loads('"\\"foo\\bar"') 
 51      u'"foo\x08ar' 
 52      >>> from StringIO import StringIO 
 53      >>> io = StringIO('["streaming API"]') 
 54      >>> simplejson.load(io) 
 55      [u'streaming API'] 
 56   
 57  Specializing JSON object decoding:: 
 58   
 59      >>> import simplejson 
 60      >>> def as_complex(dct): 
 61      ...     if '__complex__' in dct: 
 62      ...         return complex(dct['real'], dct['imag']) 
 63      ...     return dct 
 64      ...  
 65      >>> simplejson.loads('{"__complex__": true, "real": 1, "imag": 2}', 
 66      ...     object_hook=as_complex) 
 67      (1+2j) 
 68      >>> import decimal 
 69      >>> simplejson.loads('1.1', parse_float=decimal.Decimal) 
 70      Decimal("1.1") 
 71   
 72  Extending JSONEncoder:: 
 73       
 74      >>> import simplejson 
 75      >>> class ComplexEncoder(simplejson.JSONEncoder): 
 76      ...     def default(self, obj): 
 77      ...         if isinstance(obj, complex): 
 78      ...             return [obj.real, obj.imag] 
 79      ...         return simplejson.JSONEncoder.default(self, obj) 
 80      ...  
 81      >>> dumps(2 + 1j, cls=ComplexEncoder) 
 82      '[2.0, 1.0]' 
 83      >>> ComplexEncoder().encode(2 + 1j) 
 84      '[2.0, 1.0]' 
 85      >>> list(ComplexEncoder().iterencode(2 + 1j)) 
 86      ['[', '2.0', ', ', '1.0', ']'] 
 87       
 88   
 89  Using simplejson from the shell to validate and 
 90  pretty-print:: 
 91       
 92      $ echo '{"json":"obj"}' | python -msimplejson.tool 
 93      { 
 94          "json": "obj" 
 95      } 
 96      $ echo '{ 1.2:3.4}' | python -msimplejson.tool 
 97      Expecting property name: line 1 column 2 (char 2) 
 98   
 99  Note that the JSON produced by this module's default settings 
100  is a subset of YAML, so it may be used as a serializer for that as well. 
101  """ 
102  __version__ = '1.9.2' 
103  __all__ = [ 
104      'dump', 'dumps', 'load', 'loads', 
105      'JSONDecoder', 'JSONEncoder', 
106  ] 
107   
108  if __name__ == '__main__': 
109      import warnings 
110      warnings.warn('python -msimplejson is deprecated, use python -msiplejson.tool', DeprecationWarning) 
111      from django.utils.simplejson.decoder import JSONDecoder 
112      from django.utils.simplejson.encoder import JSONEncoder 
113  else: 
114      from decoder import JSONDecoder 
115      from encoder import JSONEncoder 
116   
117  _default_encoder = JSONEncoder( 
118      skipkeys=False, 
119      ensure_ascii=True, 
120      check_circular=True, 
121      allow_nan=True, 
122      indent=None, 
123      separators=None, 
124      encoding='utf-8', 
125      default=None, 
126  ) 
127   
128 -def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True, 129 allow_nan=True, cls=None, indent=None, separators=None, 130 encoding='utf-8', default=None, **kw):
131 """ 132 Serialize ``obj`` as a JSON formatted stream to ``fp`` (a 133 ``.write()``-supporting file-like object). 134 135 If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types 136 (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``) 137 will be skipped instead of raising a ``TypeError``. 138 139 If ``ensure_ascii`` is ``False``, then the some chunks written to ``fp`` 140 may be ``unicode`` instances, subject to normal Python ``str`` to 141 ``unicode`` coercion rules. Unless ``fp.write()`` explicitly 142 understands ``unicode`` (as in ``codecs.getwriter()``) this is likely 143 to cause an error. 144 145 If ``check_circular`` is ``False``, then the circular reference check 146 for container types will be skipped and a circular reference will 147 result in an ``OverflowError`` (or worse). 148 149 If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to 150 serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) 151 in strict compliance of the JSON specification, instead of using the 152 JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). 153 154 If ``indent`` is a non-negative integer, then JSON array elements and object 155 members will be pretty-printed with that indent level. An indent level 156 of 0 will only insert newlines. ``None`` is the most compact representation. 157 158 If ``separators`` is an ``(item_separator, dict_separator)`` tuple 159 then it will be used instead of the default ``(', ', ': ')`` separators. 160 ``(',', ':')`` is the most compact JSON representation. 161 162 ``encoding`` is the character encoding for str instances, default is UTF-8. 163 164 ``default(obj)`` is a function that should return a serializable version 165 of obj or raise TypeError. The default simply raises TypeError. 166 167 To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the 168 ``.default()`` method to serialize additional types), specify it with 169 the ``cls`` kwarg. 170 """ 171 # cached encoder 172 if (skipkeys is False and ensure_ascii is True and 173 check_circular is True and allow_nan is True and 174 cls is None and indent is None and separators is None and 175 encoding == 'utf-8' and default is None and not kw): 176 iterable = _default_encoder.iterencode(obj) 177 else: 178 if cls is None: 179 cls = JSONEncoder 180 iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii, 181 check_circular=check_circular, allow_nan=allow_nan, indent=indent, 182 separators=separators, encoding=encoding, 183 default=default, **kw).iterencode(obj) 184 # could accelerate with writelines in some versions of Python, at 185 # a debuggability cost 186 for chunk in iterable: 187 fp.write(chunk)
188 189
190 -def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True, 191 allow_nan=True, cls=None, indent=None, separators=None, 192 encoding='utf-8', default=None, **kw):
193 """ 194 Serialize ``obj`` to a JSON formatted ``str``. 195 196 If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types 197 (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``) 198 will be skipped instead of raising a ``TypeError``. 199 200 If ``ensure_ascii`` is ``False``, then the return value will be a 201 ``unicode`` instance subject to normal Python ``str`` to ``unicode`` 202 coercion rules instead of being escaped to an ASCII ``str``. 203 204 If ``check_circular`` is ``False``, then the circular reference check 205 for container types will be skipped and a circular reference will 206 result in an ``OverflowError`` (or worse). 207 208 If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to 209 serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in 210 strict compliance of the JSON specification, instead of using the 211 JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). 212 213 If ``indent`` is a non-negative integer, then JSON array elements and 214 object members will be pretty-printed with that indent level. An indent 215 level of 0 will only insert newlines. ``None`` is the most compact 216 representation. 217 218 If ``separators`` is an ``(item_separator, dict_separator)`` tuple 219 then it will be used instead of the default ``(', ', ': ')`` separators. 220 ``(',', ':')`` is the most compact JSON representation. 221 222 ``encoding`` is the character encoding for str instances, default is UTF-8. 223 224 ``default(obj)`` is a function that should return a serializable version 225 of obj or raise TypeError. The default simply raises TypeError. 226 227 To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the 228 ``.default()`` method to serialize additional types), specify it with 229 the ``cls`` kwarg. 230 """ 231 # cached encoder 232 if (skipkeys is False and ensure_ascii is True and 233 check_circular is True and allow_nan is True and 234 cls is None and indent is None and separators is None and 235 encoding == 'utf-8' and default is None and not kw): 236 return _default_encoder.encode(obj) 237 if cls is None: 238 cls = JSONEncoder 239 return cls( 240 skipkeys=skipkeys, ensure_ascii=ensure_ascii, 241 check_circular=check_circular, allow_nan=allow_nan, indent=indent, 242 separators=separators, encoding=encoding, default=default, 243 **kw).encode(obj)
244 245 246 _default_decoder = JSONDecoder(encoding=None, object_hook=None) 247 248
249 -def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None, 250 parse_int=None, parse_constant=None, **kw):
251 """ 252 Deserialize ``fp`` (a ``.read()``-supporting file-like object containing 253 a JSON document) to a Python object. 254 255 If the contents of ``fp`` is encoded with an ASCII based encoding other 256 than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must 257 be specified. Encodings that are not ASCII based (such as UCS-2) are 258 not allowed, and should be wrapped with 259 ``codecs.getreader(fp)(encoding)``, or simply decoded to a ``unicode`` 260 object and passed to ``loads()`` 261 262 ``object_hook`` is an optional function that will be called with the 263 result of any object literal decode (a ``dict``). The return value of 264 ``object_hook`` will be used instead of the ``dict``. This feature 265 can be used to implement custom decoders (e.g. JSON-RPC class hinting). 266 267 To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` 268 kwarg. 269 """ 270 return loads(fp.read(), 271 encoding=encoding, cls=cls, object_hook=object_hook, 272 parse_float=parse_float, parse_int=parse_int, 273 parse_constant=parse_constant, **kw)
274 275
276 -def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None, 277 parse_int=None, parse_constant=None, **kw):
278 """ 279 Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON 280 document) to a Python object. 281 282 If ``s`` is a ``str`` instance and is encoded with an ASCII based encoding 283 other than utf-8 (e.g. latin-1) then an appropriate ``encoding`` name 284 must be specified. Encodings that are not ASCII based (such as UCS-2) 285 are not allowed and should be decoded to ``unicode`` first. 286 287 ``object_hook`` is an optional function that will be called with the 288 result of any object literal decode (a ``dict``). The return value of 289 ``object_hook`` will be used instead of the ``dict``. This feature 290 can be used to implement custom decoders (e.g. JSON-RPC class hinting). 291 292 ``parse_float``, if specified, will be called with the string 293 of every JSON float to be decoded. By default this is equivalent to 294 float(num_str). This can be used to use another datatype or parser 295 for JSON floats (e.g. decimal.Decimal). 296 297 ``parse_int``, if specified, will be called with the string 298 of every JSON int to be decoded. By default this is equivalent to 299 int(num_str). This can be used to use another datatype or parser 300 for JSON integers (e.g. float). 301 302 ``parse_constant``, if specified, will be called with one of the 303 following strings: -Infinity, Infinity, NaN, null, true, false. 304 This can be used to raise an exception if invalid JSON numbers 305 are encountered. 306 307 To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` 308 kwarg. 309 """ 310 if (cls is None and encoding is None and object_hook is None and 311 parse_int is None and parse_float is None and 312 parse_constant is None and not kw): 313 return _default_decoder.decode(s) 314 if cls is None: 315 cls = JSONDecoder 316 if object_hook is not None: 317 kw['object_hook'] = object_hook 318 if parse_float is not None: 319 kw['parse_float'] = parse_float 320 if parse_int is not None: 321 kw['parse_int'] = parse_int 322 if parse_constant is not None: 323 kw['parse_constant'] = parse_constant 324 return cls(encoding=encoding, **kw).decode(s)
325 326 327 # 328 # Compatibility cruft from other libraries 329 # 330 331
332 -def decode(s):
333 """ 334 demjson, python-cjson API compatibility hook. Use loads(s) instead. 335 """ 336 import warnings 337 warnings.warn("simplejson.loads(s) should be used instead of decode(s)", 338 DeprecationWarning) 339 return loads(s)
340 341
342 -def encode(obj):
343 """ 344 demjson, python-cjson compatibility hook. Use dumps(s) instead. 345 """ 346 import warnings 347 warnings.warn("simplejson.dumps(s) should be used instead of encode(s)", 348 DeprecationWarning) 349 return dumps(obj)
350 351
352 -def read(s):
353 """ 354 jsonlib, JsonUtils, python-json, json-py API compatibility hook. 355 Use loads(s) instead. 356 """ 357 import warnings 358 warnings.warn("simplejson.loads(s) should be used instead of read(s)", 359 DeprecationWarning) 360 return loads(s)
361 362
363 -def write(obj):
364 """ 365 jsonlib, JsonUtils, python-json, json-py API compatibility hook. 366 Use dumps(s) instead. 367 """ 368 import warnings 369 warnings.warn("simplejson.dumps(s) should be used instead of write(s)", 370 DeprecationWarning) 371 return dumps(obj)
372 373 374 if __name__ == '__main__': 375 import simplejson.tool 376 simplejson.tool.main() 377