| | """Implementation of JSONDecoder |
| | """ |
| | import re |
| |
|
| | from json import scanner |
| | try: |
| | from _json import scanstring as c_scanstring |
| | except ImportError: |
| | c_scanstring = None |
| |
|
| | __all__ = ['JSONDecoder', 'JSONDecodeError'] |
| |
|
| | FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL |
| |
|
| | NaN = float('nan') |
| | PosInf = float('inf') |
| | NegInf = float('-inf') |
| |
|
| |
|
| | class JSONDecodeError(ValueError): |
| | """Subclass of ValueError with the following additional properties: |
| | |
| | msg: The unformatted error message |
| | doc: The JSON document being parsed |
| | pos: The start index of doc where parsing failed |
| | lineno: The line corresponding to pos |
| | colno: The column corresponding to pos |
| | |
| | """ |
| | |
| | def __init__(self, msg, doc, pos): |
| | lineno = doc.count('\n', 0, pos) + 1 |
| | colno = pos - doc.rfind('\n', 0, pos) |
| | errmsg = '%s: line %d column %d (char %d)' % (msg, lineno, colno, pos) |
| | ValueError.__init__(self, errmsg) |
| | self.msg = msg |
| | self.doc = doc |
| | self.pos = pos |
| | self.lineno = lineno |
| | self.colno = colno |
| |
|
| | def __reduce__(self): |
| | return self.__class__, (self.msg, self.doc, self.pos) |
| |
|
| |
|
| | _CONSTANTS = { |
| | '-Infinity': NegInf, |
| | 'Infinity': PosInf, |
| | 'NaN': NaN, |
| | } |
| |
|
| |
|
| | STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS) |
| | BACKSLASH = { |
| | '"': '"', '\\': '\\', '/': '/', |
| | 'b': '\b', 'f': '\f', 'n': '\n', 'r': '\r', 't': '\t', |
| | } |
| |
|
| | def _decode_uXXXX(s, pos): |
| | esc = s[pos + 1:pos + 5] |
| | if len(esc) == 4 and esc[1] not in 'xX': |
| | try: |
| | return int(esc, 16) |
| | except ValueError: |
| | pass |
| | msg = "Invalid \\uXXXX escape" |
| | raise JSONDecodeError(msg, s, pos) |
| |
|
| | def py_scanstring(s, end, strict=True, |
| | _b=BACKSLASH, _m=STRINGCHUNK.match): |
| | """Scan the string s for a JSON string. End is the index of the |
| | character in s after the quote that started the JSON string. |
| | Unescapes all valid JSON string escape sequences and raises ValueError |
| | on attempt to decode an invalid string. If strict is False then literal |
| | control characters are allowed in the string. |
| | |
| | Returns a tuple of the decoded string and the index of the character in s |
| | after the end quote.""" |
| | chunks = [] |
| | _append = chunks.append |
| | begin = end - 1 |
| | while 1: |
| | chunk = _m(s, end) |
| | if chunk is None: |
| | raise JSONDecodeError("Unterminated string starting at", s, begin) |
| | end = chunk.end() |
| | content, terminator = chunk.groups() |
| | |
| | if content: |
| | _append(content) |
| | |
| | |
| | if terminator == '"': |
| | break |
| | elif terminator != '\\': |
| | if strict: |
| | |
| | msg = "Invalid control character {0!r} at".format(terminator) |
| | raise JSONDecodeError(msg, s, end) |
| | else: |
| | _append(terminator) |
| | continue |
| | try: |
| | esc = s[end] |
| | except IndexError: |
| | raise JSONDecodeError("Unterminated string starting at", |
| | s, begin) from None |
| | |
| | if esc != 'u': |
| | try: |
| | char = _b[esc] |
| | except KeyError: |
| | msg = "Invalid \\escape: {0!r}".format(esc) |
| | raise JSONDecodeError(msg, s, end) |
| | end += 1 |
| | else: |
| | uni = _decode_uXXXX(s, end) |
| | end += 5 |
| | if 0xd800 <= uni <= 0xdbff and s[end:end + 2] == '\\u': |
| | uni2 = _decode_uXXXX(s, end + 1) |
| | if 0xdc00 <= uni2 <= 0xdfff: |
| | uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00)) |
| | end += 6 |
| | char = chr(uni) |
| | _append(char) |
| | return ''.join(chunks), end |
| |
|
| |
|
| | |
| | scanstring = c_scanstring or py_scanstring |
| |
|
| | WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS) |
| | WHITESPACE_STR = ' \t\n\r' |
| |
|
| |
|
| | def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook, |
| | memo=None, _w=WHITESPACE.match, _ws=WHITESPACE_STR): |
| | s, end = s_and_end |
| | pairs = [] |
| | pairs_append = pairs.append |
| | |
| | if memo is None: |
| | memo = {} |
| | memo_get = memo.setdefault |
| | |
| | |
| | nextchar = s[end:end + 1] |
| | |
| | if nextchar != '"': |
| | if nextchar in _ws: |
| | end = _w(s, end).end() |
| | nextchar = s[end:end + 1] |
| | |
| | if nextchar == '}': |
| | if object_pairs_hook is not None: |
| | result = object_pairs_hook(pairs) |
| | return result, end + 1 |
| | pairs = {} |
| | if object_hook is not None: |
| | pairs = object_hook(pairs) |
| | return pairs, end + 1 |
| | elif nextchar != '"': |
| | raise JSONDecodeError( |
| | "Expecting property name enclosed in double quotes", s, end) |
| | end += 1 |
| | while True: |
| | key, end = scanstring(s, end, strict) |
| | key = memo_get(key, key) |
| | |
| | |
| | if s[end:end + 1] != ':': |
| | end = _w(s, end).end() |
| | if s[end:end + 1] != ':': |
| | raise JSONDecodeError("Expecting ':' delimiter", s, end) |
| | end += 1 |
| |
|
| | try: |
| | if s[end] in _ws: |
| | end += 1 |
| | if s[end] in _ws: |
| | end = _w(s, end + 1).end() |
| | except IndexError: |
| | pass |
| |
|
| | try: |
| | value, end = scan_once(s, end) |
| | except StopIteration as err: |
| | raise JSONDecodeError("Expecting value", s, err.value) from None |
| | pairs_append((key, value)) |
| | try: |
| | nextchar = s[end] |
| | if nextchar in _ws: |
| | end = _w(s, end + 1).end() |
| | nextchar = s[end] |
| | except IndexError: |
| | nextchar = '' |
| | end += 1 |
| |
|
| | if nextchar == '}': |
| | break |
| | elif nextchar != ',': |
| | raise JSONDecodeError("Expecting ',' delimiter", s, end - 1) |
| | end = _w(s, end).end() |
| | nextchar = s[end:end + 1] |
| | end += 1 |
| | if nextchar != '"': |
| | raise JSONDecodeError( |
| | "Expecting property name enclosed in double quotes", s, end - 1) |
| | if object_pairs_hook is not None: |
| | result = object_pairs_hook(pairs) |
| | return result, end |
| | pairs = dict(pairs) |
| | if object_hook is not None: |
| | pairs = object_hook(pairs) |
| | return pairs, end |
| |
|
| | def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR): |
| | s, end = s_and_end |
| | values = [] |
| | nextchar = s[end:end + 1] |
| | if nextchar in _ws: |
| | end = _w(s, end + 1).end() |
| | nextchar = s[end:end + 1] |
| | |
| | if nextchar == ']': |
| | return values, end + 1 |
| | _append = values.append |
| | while True: |
| | try: |
| | value, end = scan_once(s, end) |
| | except StopIteration as err: |
| | raise JSONDecodeError("Expecting value", s, err.value) from None |
| | _append(value) |
| | nextchar = s[end:end + 1] |
| | if nextchar in _ws: |
| | end = _w(s, end + 1).end() |
| | nextchar = s[end:end + 1] |
| | end += 1 |
| | if nextchar == ']': |
| | break |
| | elif nextchar != ',': |
| | raise JSONDecodeError("Expecting ',' delimiter", s, end - 1) |
| | try: |
| | if s[end] in _ws: |
| | end += 1 |
| | if s[end] in _ws: |
| | end = _w(s, end + 1).end() |
| | except IndexError: |
| | pass |
| |
|
| | return values, end |
| |
|
| |
|
| | class JSONDecoder(object): |
| | """Simple JSON <https://json.org> decoder |
| | |
| | Performs the following translations in decoding by default: |
| | |
| | +---------------+-------------------+ |
| | | JSON | Python | |
| | +===============+===================+ |
| | | object | dict | |
| | +---------------+-------------------+ |
| | | array | list | |
| | +---------------+-------------------+ |
| | | string | str | |
| | +---------------+-------------------+ |
| | | number (int) | int | |
| | +---------------+-------------------+ |
| | | number (real) | float | |
| | +---------------+-------------------+ |
| | | true | True | |
| | +---------------+-------------------+ |
| | | false | False | |
| | +---------------+-------------------+ |
| | | null | None | |
| | +---------------+-------------------+ |
| | |
| | It also understands ``NaN``, ``Infinity``, and ``-Infinity`` as |
| | their corresponding ``float`` values, which is outside the JSON spec. |
| | |
| | """ |
| |
|
| | def __init__(self, *, object_hook=None, parse_float=None, |
| | parse_int=None, parse_constant=None, strict=True, |
| | object_pairs_hook=None): |
| | """``object_hook``, if specified, will be called with the result |
| | of every JSON object decoded and its return value will be used in |
| | place of the given ``dict``. This can be used to provide custom |
| | deserializations (e.g. to support JSON-RPC class hinting). |
| | |
| | ``object_pairs_hook``, if specified will be called with the result of |
| | every JSON object decoded with an ordered list of pairs. The return |
| | value of ``object_pairs_hook`` will be used instead of the ``dict``. |
| | This feature can be used to implement custom decoders. |
| | If ``object_hook`` is also defined, the ``object_pairs_hook`` takes |
| | priority. |
| | |
| | ``parse_float``, if specified, will be called with the string |
| | of every JSON float to be decoded. By default this is equivalent to |
| | float(num_str). This can be used to use another datatype or parser |
| | for JSON floats (e.g. decimal.Decimal). |
| | |
| | ``parse_int``, if specified, will be called with the string |
| | of every JSON int to be decoded. By default this is equivalent to |
| | int(num_str). This can be used to use another datatype or parser |
| | for JSON integers (e.g. float). |
| | |
| | ``parse_constant``, if specified, will be called with one of the |
| | following strings: -Infinity, Infinity, NaN. |
| | This can be used to raise an exception if invalid JSON numbers |
| | are encountered. |
| | |
| | If ``strict`` is false (true is the default), then control |
| | characters will be allowed inside strings. Control characters in |
| | this context are those with character codes in the 0-31 range, |
| | including ``'\\t'`` (tab), ``'\\n'``, ``'\\r'`` and ``'\\0'``. |
| | """ |
| | self.object_hook = object_hook |
| | self.parse_float = parse_float or float |
| | self.parse_int = parse_int or int |
| | self.parse_constant = parse_constant or _CONSTANTS.__getitem__ |
| | self.strict = strict |
| | self.object_pairs_hook = object_pairs_hook |
| | self.parse_object = JSONObject |
| | self.parse_array = JSONArray |
| | self.parse_string = scanstring |
| | self.memo = {} |
| | self.scan_once = scanner.make_scanner(self) |
| |
|
| |
|
| | def decode(self, s, _w=WHITESPACE.match): |
| | """Return the Python representation of ``s`` (a ``str`` instance |
| | containing a JSON document). |
| | |
| | """ |
| | obj, end = self.raw_decode(s, idx=_w(s, 0).end()) |
| | end = _w(s, end).end() |
| | if end != len(s): |
| | raise JSONDecodeError("Extra data", s, end) |
| | return obj |
| |
|
| | def raw_decode(self, s, idx=0): |
| | """Decode a JSON document from ``s`` (a ``str`` beginning with |
| | a JSON document) and return a 2-tuple of the Python |
| | representation and the index in ``s`` where the document ended. |
| | |
| | This can be used to decode a JSON document from a string that may |
| | have extraneous data at the end. |
| | |
| | """ |
| | try: |
| | obj, end = self.scan_once(s, idx) |
| | except StopIteration as err: |
| | raise JSONDecodeError("Expecting value", s, err.value) from None |
| | return obj, end |
| |
|