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authorJacob Kaplan-Moss <jacob@jacobian.org>2006-06-28 20:59:49 +0000
committerJacob Kaplan-Moss <jacob@jacobian.org>2006-06-28 20:59:49 +0000
commitf44e7acb17738cb222a0d8390eac480488241d15 (patch)
tree1e7a9572cb2159ef9ffab81aaf1a9de7e1a88116 /django/utils/simplejson/encoder.py
parentaab3a418ac9293bb4abd7670f65d930cb0426d58 (diff)
Added Bob Ippolito's simplejson (http://undefined.org/python/#simplejson) as {{{django.auth.simplejson}}}. This is version 1.3 of simplejson. Thanks to Bob for his code and his permission to include it.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@3232 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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+"""
+Implementation of JSONEncoder
+"""
+import re
+
+# this should match any kind of infinity
+INFCHARS = re.compile(r'[infINF]')
+ESCAPE = re.compile(r'[\x00-\x19\\"\b\f\n\r\t]')
+ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
+ESCAPE_DCT = {
+ '\\': '\\\\',
+ '"': '\\"',
+ '\b': '\\b',
+ '\f': '\\f',
+ '\n': '\\n',
+ '\r': '\\r',
+ '\t': '\\t',
+}
+for i in range(20):
+ ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))
+
+def floatstr(o, allow_nan=True):
+ s = str(o)
+ # If the first non-sign is a digit then it's not a special value
+ if (o < 0.0 and s[1].isdigit()) or s[0].isdigit():
+ return s
+ elif not allow_nan:
+ raise ValueError("Out of range float values are not JSON compliant: %r"
+ % (o,))
+ # These are the string representations on the platforms I've tried
+ if s == 'nan':
+ return 'NaN'
+ if s == 'inf':
+ return 'Infinity'
+ if s == '-inf':
+ return '-Infinity'
+ # NaN should either be inequal to itself, or equal to everything
+ if o != o or o == 0.0:
+ return 'NaN'
+ # Last ditch effort, assume inf
+ if o < 0:
+ return '-Infinity'
+ return 'Infinity'
+
+def 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) + '"'
+
+def encode_basestring_ascii(s):
+ def replace(match):
+ s = match.group(0)
+ try:
+ return ESCAPE_DCT[s]
+ except KeyError:
+ return '\\u%04x' % (ord(s),)
+ return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'
+
+
+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, unicode | string |
+ +-------------------+---------------+
+ | int, long, 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``).
+ """
+ __all__ = ['__init__', 'default', 'encode', 'iterencode']
+ def __init__(self, skipkeys=False, ensure_ascii=True,
+ check_circular=True, allow_nan=True, sort_keys=False):
+ """
+ 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, long, 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 unicode characters escaped. If
+ ensure_ascii is false, the output will be unicode object.
+
+ 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.
+ """
+
+ self.skipkeys = skipkeys
+ self.ensure_ascii = ensure_ascii
+ self.check_circular = check_circular
+ self.allow_nan = allow_nan
+ self.sort_keys = sort_keys
+
+ def _iterencode_list(self, lst, markers=None):
+ 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
+ yield '['
+ first = True
+ for value in lst:
+ if first:
+ first = False
+ else:
+ yield ', '
+ for chunk in self._iterencode(value, markers):
+ yield chunk
+ yield ']'
+ if markers is not None:
+ del markers[markerid]
+
+ def _iterencode_dict(self, dct, markers=None):
+ 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 '{'
+ first = True
+ if self.ensure_ascii:
+ encoder = encode_basestring_ascii
+ else:
+ encoder = encode_basestring
+ allow_nan = self.allow_nan
+ if self.sort_keys:
+ keys = dct.keys()
+ keys.sort()
+ items = [(k,dct[k]) for k in keys]
+ else:
+ items = dct.iteritems()
+ for key, value in items:
+ if isinstance(key, basestring):
+ 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):
+ key = floatstr(key, allow_nan)
+ elif isinstance(key, (int, long)):
+ key = str(key)
+ elif key is True:
+ key = 'true'
+ elif key is False:
+ key = 'false'
+ elif key is None:
+ key = 'null'
+ elif self.skipkeys:
+ continue
+ else:
+ raise TypeError("key %r is not a string" % (key,))
+ if first:
+ first = False
+ else:
+ yield ', '
+ yield encoder(key)
+ yield ': '
+ for chunk in self._iterencode(value, markers):
+ yield chunk
+ yield '}'
+ if markers is not None:
+ del markers[markerid]
+
+ def _iterencode(self, o, markers=None):
+ if isinstance(o, basestring):
+ if self.ensure_ascii:
+ encoder = encode_basestring_ascii
+ else:
+ encoder = encode_basestring
+ 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, long)):
+ yield str(o)
+ elif isinstance(o, float):
+ yield floatstr(o, self.allow_nan)
+ elif isinstance(o, (list, tuple)):
+ for chunk in self._iterencode_list(o, markers):
+ yield chunk
+ elif isinstance(o, dict):
+ for chunk in self._iterencode_dict(o, markers):
+ yield chunk
+ else:
+ if markers is not None:
+ markerid = id(o)
+ if markerid in markers:
+ raise ValueError("Circular reference detected")
+ markers[markerid] = o
+ for chunk in self._iterencode_default(o, markers):
+ yield chunk
+ if markers is not None:
+ del markers[markerid]
+
+ def _iterencode_default(self, o, markers=None):
+ newobj = self.default(o)
+ return self._iterencode(newobj, markers)
+
+ 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)
+ return JSONEncoder.default(self, o)
+ """
+ raise TypeError("%r is not JSON serializable" % (o,))
+
+ def encode(self, o):
+ """
+ Return a JSON string representation of a Python data structure.
+
+ >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
+ '{"foo":["bar", "baz"]}'
+ """
+ # This doesn't pass the iterator directly to ''.join() because it
+ # sucks at reporting exceptions. It's going to do this internally
+ # anyway because it uses PySequence_Fast or similar.
+ chunks = list(self.iterencode(o))
+ return ''.join(chunks)
+
+ def iterencode(self, o):
+ """
+ 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
+ return self._iterencode(o, markers)
+
+__all__ = ['JSONEncoder']