Merged revisions 62734,62736,62748,62769 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r62734 | brett.cannon | 2008-05-05 22:21:38 +0200 (Mon, 05 May 2008) | 5 lines
Add the 'json' package. Code taken from simplejson 1.9 and contributed by Bob
Ippolito.
Closes issue #2750.
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r62736 | georg.brandl | 2008-05-05 22:53:39 +0200 (Mon, 05 May 2008) | 2 lines
Fix JSON module docs.
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r62748 | benjamin.peterson | 2008-05-06 04:51:10 +0200 (Tue, 06 May 2008) | 2 lines
PEP 8 nits in json package
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r62769 | christian.heimes | 2008-05-06 18:18:41 +0200 (Tue, 06 May 2008) | 2 lines
Intern static string
Use float constructors instead of magic code for float constants
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diff --git a/Lib/json/encoder.py b/Lib/json/encoder.py
new file mode 100644
index 0000000..4cb3660
--- /dev/null
+++ b/Lib/json/encoder.py
@@ -0,0 +1,384 @@
+"""Implementation of JSONEncoder
+"""
+
+import re
+
+try:
+ from _json import encode_basestring_ascii as c_encode_basestring_ascii
+except ImportError:
+ c_encode_basestring_ascii = None
+
+__all__ = ['JSONEncoder']
+
+ESCAPE = re.compile(r'[\x00-\x1f\\"\b\f\n\r\t]')
+ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')
+HAS_UTF8 = re.compile(r'[\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))
+
+# Assume this produces an infinity on all machines (probably not guaranteed)
+INFINITY = float('1e66666')
+FLOAT_REPR = repr
+
+def floatstr(o, allow_nan=True):
+ # 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 == INFINITY:
+ text = 'Infinity'
+ elif o == -INFINITY:
+ text = '-Infinity'
+ else:
+ return FLOAT_REPR(o)
+
+ if not allow_nan:
+ msg = "Out of range float values are not JSON compliant: " + repr(o)
+ raise ValueError(msg)
+
+ return text
+
+
+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 py_encode_basestring_ascii(s):
+ if isinstance(s, bytes): # and HAS_UTF8.search(s) is not None:
+ s = s.decode('utf-8')
+ 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)
+ 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)) + '"'
+
+
+if c_encode_basestring_ascii is not None:
+ encode_basestring_ascii = c_encode_basestring_ascii
+else:
+ encode_basestring_ascii = 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:
+
+ +-------------------+---------------+
+ | 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']
+ 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, encoding='utf-8', 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, 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.
+
+ 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 a (item_separator, key_separator)
+ tuple. The default is (', ', ': '). 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``.
+
+ If encoding is not None, then all input strings will be
+ transformed into unicode using that encoding prior to JSON-encoding.
+ The default is UTF-8.
+
+ """
+ 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
+ self.current_indent_level = 0
+ if separators is not None:
+ self.item_separator, self.key_separator = separators
+ if default is not None:
+ self.default = default
+ self.encoding = encoding
+
+ def _newline_indent(self):
+ return '\n' + (' ' * (self.indent * self.current_indent_level))
+
+ 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 '['
+ if self.indent is not None:
+ self.current_indent_level += 1
+ newline_indent = self._newline_indent()
+ separator = self.item_separator + newline_indent
+ yield newline_indent
+ else:
+ newline_indent = None
+ separator = self.item_separator
+ first = True
+ for value in lst:
+ if first:
+ first = False
+ else:
+ yield separator
+ for chunk in self._iterencode(value, markers):
+ yield chunk
+ if newline_indent is not None:
+ self.current_indent_level -= 1
+ yield self._newline_indent()
+ 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 '{'
+ key_separator = self.key_separator
+ if self.indent is not None:
+ self.current_indent_level += 1
+ newline_indent = self._newline_indent()
+ item_separator = self.item_separator + newline_indent
+ yield newline_indent
+ else:
+ newline_indent = None
+ item_separator = self.item_separator
+ first = True
+ if self.ensure_ascii:
+ encoder = encode_basestring_ascii
+ else:
+ encoder = encode_basestring
+ allow_nan = self.allow_nan
+ if self.sort_keys:
+ keys = list(dct.keys())
+ keys.sort()
+ items = [(k, dct[k]) for k in keys]
+ else:
+ items = iter(dct.items())
+ _encoding = self.encoding
+ _do_decode = (_encoding is not None
+ and not (_encoding == 'utf-8'))
+ for key, value in items:
+ if isinstance(key, str):
+ if _do_decode:
+ key = key.decode(_encoding)
+ elif 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):
+ key = floatstr(key, allow_nan)
+ elif isinstance(key, (int, int)):
+ 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 {0!r} is not a string".format(key))
+ if first:
+ first = False
+ else:
+ yield item_separator
+ yield encoder(key)
+ yield key_separator
+ for chunk in self._iterencode(value, markers):
+ yield chunk
+ if newline_indent is not None:
+ self.current_indent_level -= 1
+ yield self._newline_indent()
+ yield '}'
+ if markers is not None:
+ del markers[markerid]
+
+ def _iterencode(self, o, markers=None):
+ if isinstance(o, str):
+ if self.ensure_ascii:
+ encoder = encode_basestring_ascii
+ else:
+ encoder = encode_basestring
+ _encoding = self.encoding
+ if (_encoding is not None and isinstance(o, str)
+ and not (_encoding == 'utf-8')):
+ o = o.decode(_encoding)
+ 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, int)):
+ 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(repr(o) + " is not JSON serializable")
+
+ def encode(self, o):
+ """Return a JSON string representation of a Python data structure.
+
+ >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
+ '{"foo": ["bar", "baz"]}'
+
+ """
+ # This is for extremely simple cases and benchmarks.
+ if isinstance(o, (str, bytes)):
+ if isinstance(o, bytes):
+ _encoding = self.encoding
+ if (_encoding is not None
+ and not (_encoding == 'utf-8')):
+ o = o.decode(_encoding)
+ 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 = 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)