cybertools/util/json.py
helmutm cda7a9624b add json decoder
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@2986 fd906abe-77d9-0310-91a1-e0d9ade77398
2008-11-14 09:04:38 +00:00

666 lines
21 KiB
Python

"""
A simple, fast, extensible JSON encoder
JSON (JavaScript Object Notation) <http://json.org> is a subset of
JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data
interchange format."""
"""
This is a stripped-down version of simplejson
by Bob Ippolito, http://undefined.org/python/
Copyright (c) 2006 Bob Ippolito
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""
import re, sys
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%04x' % (i,))
# Assume this produces an infinity on all machines (probably not guaranteed)
INFINITY = float('1e66666')
FLOAT_REPR = repr
def floatstr(o, allow_nan=True):
if o != o:
text = 'NaN'
elif o == INFINITY:
text = 'Infinity'
elif o == -INFINITY:
text = '-Infinity'
else:
return FLOAT_REPR(o)
if not allow_nan:
raise ValueError("Out of range float values are not JSON compliant: %r"
% (o,))
return text
def encode_basestring(s):
def replace(match):
return ESCAPE_DCT[match.group(0)]
return '"' + ESCAPE.sub(replace, s) + '"'
def py_encode_basestring_ascii(s):
if isinstance(s, str) 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%04x' % (n,)
else:
# surrogate pair
n -= 0x10000
s1 = 0xd800 | ((n >> 10) & 0x3ff)
s2 = 0xdc00 | (n & 0x3ff)
return '\\u%04x\\u%04x' % (s1, s2)
return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'
encode_basestring_ascii = py_encode_basestring_ascii
class JSONEncoder(object):
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):
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 = dct.keys()
keys.sort()
items = [(k, dct[k]) for k in keys]
else:
items = dct.iteritems()
_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, 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 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, basestring):
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, 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):
raise TypeError("%r is not JSON serializable" % (o,))
def encode(self, o):
if isinstance(o, basestring):
if isinstance(o, str):
_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)
chunks = list(self.iterencode(o))
return ''.join(chunks)
def iterencode(self, o):
if self.check_circular:
markers = {}
else:
markers = None
return self._iterencode(o, markers)
_default_encoder = JSONEncoder(
skipkeys=False,
ensure_ascii=True,
check_circular=True,
allow_nan=True,
indent=None,
separators=None,
encoding='utf-8',
default=None,
)
"""
Implementation of JSONDecoder
"""
import sre_parse
import sre_compile
import sre_constants
from sre_constants import BRANCH, SUBPATTERN
FLAGS = (re.VERBOSE | re.MULTILINE | re.DOTALL)
class Scanner(object):
def __init__(self, lexicon, flags=FLAGS):
self.actions = [None]
# Combine phrases into a compound pattern
s = sre_parse.Pattern()
s.flags = flags
p = []
for idx, token in enumerate(lexicon):
phrase = token.pattern
try:
subpattern = sre_parse.SubPattern(s,
[(SUBPATTERN, (idx + 1, sre_parse.parse(phrase, flags)))])
except sre_constants.error:
raise
p.append(subpattern)
self.actions.append(token)
s.groups = len(p) + 1 # NOTE(guido): Added to make SRE validation work
p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
self.scanner = sre_compile.compile(p)
def iterscan(self, string, idx=0, context=None):
"""
Yield match, end_idx for each match
"""
match = self.scanner.scanner(string, idx).match
actions = self.actions
lastend = idx
end = len(string)
while True:
m = match()
if m is None:
break
matchbegin, matchend = m.span()
if lastend == matchend:
break
action = actions[m.lastindex]
if action is not None:
rval, next_pos = action(m, context)
if next_pos is not None and next_pos != matchend:
# "fast forward" the scanner
matchend = next_pos
match = self.scanner.scanner(string, matchend).match
yield rval, matchend
lastend = matchend
def pattern(pattern, flags=FLAGS):
def decorator(fn):
fn.pattern = pattern
fn.regex = re.compile(pattern, flags)
return fn
return decorator
def _floatconstants():
import struct
import sys
_BYTES = '7FF80000000000007FF0000000000000'.decode('hex')
if sys.byteorder != 'big':
_BYTES = _BYTES[:8][::-1] + _BYTES[8:][::-1]
nan, inf = struct.unpack('dd', _BYTES)
return nan, inf, -inf
NaN, PosInf, NegInf = _floatconstants()
def linecol(doc, pos):
lineno = doc.count('\n', 0, pos) + 1
if lineno == 1:
colno = pos
else:
colno = pos - doc.rindex('\n', 0, pos)
return lineno, colno
def errmsg(msg, doc, pos, end=None):
lineno, colno = linecol(doc, pos)
if end is None:
return '%s: line %d column %d (char %d)' % (msg, lineno, colno, pos)
endlineno, endcolno = linecol(doc, end)
return '%s: line %d column %d - line %d column %d (char %d - %d)' % (
msg, lineno, colno, endlineno, endcolno, pos, end)
_CONSTANTS = {
'-Infinity': NegInf,
'Infinity': PosInf,
'NaN': NaN,
'true': True,
'false': False,
'null': None,
}
def JSONConstant(match, context, c=_CONSTANTS):
s = match.group(0)
fn = getattr(context, 'parse_constant', None)
if fn is None:
rval = c[s]
else:
rval = fn(s)
return rval, None
pattern('(-?Infinity|NaN|true|false|null)')(JSONConstant)
def JSONNumber(match, context):
match = JSONNumber.regex.match(match.string, *match.span())
integer, frac, exp = match.groups()
if frac or exp:
fn = getattr(context, 'parse_float', None) or float
res = fn(integer + (frac or '') + (exp or ''))
else:
fn = getattr(context, 'parse_int', None) or int
res = fn(integer)
return res, None
pattern(r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?')(JSONNumber)
STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS)
BACKSLASH = {
'"': u'"', '\\': u'\\', '/': u'/',
'b': u'\b', 'f': u'\f', 'n': u'\n', 'r': u'\r', 't': u'\t',
}
DEFAULT_ENCODING = "utf-8"
def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHUNK.match):
if encoding is None:
encoding = DEFAULT_ENCODING
chunks = []
_append = chunks.append
begin = end - 1
while 1:
chunk = _m(s, end)
if chunk is None:
raise ValueError(
errmsg("Unterminated string starting at", s, begin))
end = chunk.end()
content, terminator = chunk.groups()
if content:
if not isinstance(content, unicode):
content = unicode(content, encoding)
_append(content)
if terminator == '"':
break
elif terminator != '\\':
if strict:
raise ValueError(errmsg("Invalid control character %r at", s, end))
else:
_append(terminator)
continue
try:
esc = s[end]
except IndexError:
raise ValueError(
errmsg("Unterminated string starting at", s, begin))
if esc != 'u':
try:
m = _b[esc]
except KeyError:
raise ValueError(
errmsg("Invalid \\escape: %r" % (esc,), s, end))
end += 1
else:
esc = s[end + 1:end + 5]
next_end = end + 5
msg = "Invalid \\uXXXX escape"
try:
if len(esc) != 4:
raise ValueError
uni = int(esc, 16)
if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
if not s[end + 5:end + 7] == '\\u':
raise ValueError
esc2 = s[end + 7:end + 11]
if len(esc2) != 4:
raise ValueError
uni2 = int(esc2, 16)
uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
next_end += 6
m = unichr(uni)
except ValueError:
raise ValueError(errmsg(msg, s, end))
end = next_end
_append(m)
return u''.join(chunks), end
scanstring = py_scanstring
def JSONString(match, context):
encoding = getattr(context, 'encoding', None)
strict = getattr(context, 'strict', True)
return scanstring(match.string, match.end(), encoding, strict)
pattern(r'"')(JSONString)
WHITESPACE = re.compile(r'\s*', FLAGS)
def JSONObject(match, context, _w=WHITESPACE.match):
pairs = {}
s = match.string
end = _w(s, match.end()).end()
nextchar = s[end:end + 1]
# Trivial empty object
if nextchar == '}':
return pairs, end + 1
if nextchar != '"':
raise ValueError(errmsg("Expecting property name", s, end))
end += 1
encoding = getattr(context, 'encoding', None)
strict = getattr(context, 'strict', True)
iterscan = JSONScanner.iterscan
while True:
key, end = scanstring(s, end, encoding, strict)
end = _w(s, end).end()
if s[end:end + 1] != ':':
raise ValueError(errmsg("Expecting : delimiter", s, end))
end = _w(s, end + 1).end()
try:
value, end = iterscan(s, idx=end, context=context).next()
except StopIteration:
raise ValueError(errmsg("Expecting object", s, end))
pairs[key] = value
end = _w(s, end).end()
nextchar = s[end:end + 1]
end += 1
if nextchar == '}':
break
if nextchar != ',':
raise ValueError(errmsg("Expecting , delimiter", s, end - 1))
end = _w(s, end).end()
nextchar = s[end:end + 1]
end += 1
if nextchar != '"':
raise ValueError(errmsg("Expecting property name", s, end - 1))
object_hook = getattr(context, 'object_hook', None)
if object_hook is not None:
pairs = object_hook(pairs)
return pairs, end
pattern(r'{')(JSONObject)
def JSONArray(match, context, _w=WHITESPACE.match):
values = []
s = match.string
end = _w(s, match.end()).end()
# Look-ahead for trivial empty array
nextchar = s[end:end + 1]
if nextchar == ']':
return values, end + 1
iterscan = JSONScanner.iterscan
while True:
try:
value, end = iterscan(s, idx=end, context=context).next()
except StopIteration:
raise ValueError(errmsg("Expecting object", s, end))
values.append(value)
end = _w(s, end).end()
nextchar = s[end:end + 1]
end += 1
if nextchar == ']':
break
if nextchar != ',':
raise ValueError(errmsg("Expecting , delimiter", s, end))
end = _w(s, end).end()
return values, end
pattern(r'\[')(JSONArray)
ANYTHING = [
JSONObject,
JSONArray,
JSONString,
JSONConstant,
JSONNumber,
]
JSONScanner = Scanner(ANYTHING)
class JSONDecoder(object):
_scanner = Scanner(ANYTHING)
__all__ = ['__init__', 'decode', 'raw_decode']
def __init__(self, encoding=None, object_hook=None, parse_float=None,
parse_int=None, parse_constant=None, strict=True):
self.encoding = encoding
self.object_hook = object_hook
self.parse_float = parse_float
self.parse_int = parse_int
self.parse_constant = parse_constant
self.strict = strict
def decode(self, s, _w=WHITESPACE.match):
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
end = _w(s, end).end()
if end != len(s):
raise ValueError(errmsg("Extra data", s, end, len(s)))
return obj
def raw_decode(self, s, **kw):
kw.setdefault('context', self)
try:
obj, end = self._scanner.iterscan(s, **kw).next()
except StopIteration:
raise ValueError("No JSON object could be decoded")
return obj, end
_default_decoder = JSONDecoder(encoding=None, object_hook=None)
# public functions
def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True,
allow_nan=True, cls=None, indent=None, separators=None,
encoding='utf-8', default=None, **kw):
if (skipkeys is False and ensure_ascii is True and
check_circular is True and allow_nan is True and
cls is None and indent is None and separators is None and
encoding == 'utf-8' and default is None and not kw):
return _default_encoder.encode(obj)
if cls is None:
cls = JSONEncoder
return cls(
skipkeys=skipkeys, ensure_ascii=ensure_ascii,
check_circular=check_circular, allow_nan=allow_nan, indent=indent,
separators=separators, encoding=encoding, default=default,
**kw).encode(obj)
def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None,
parse_int=None, parse_constant=None, **kw):
if (cls is None and encoding is None and object_hook is None and
parse_int is None and parse_float is None and
parse_constant is None and not kw):
return _default_decoder.decode(s)
if cls is None:
cls = JSONDecoder
if object_hook is not None:
kw['object_hook'] = object_hook
if parse_float is not None:
kw['parse_float'] = parse_float
if parse_int is not None:
kw['parse_int'] = parse_int
if parse_constant is not None:
kw['parse_constant'] = parse_constant
return cls(encoding=encoding, **kw).decode(s)