commit: b0a60ce2032172aeaaf27fe3866ab72768f10cb2
parent e52e8b8111cf7ca27daef184bacd926865e951b1
Author: dirkf <fieldhouse@gmx.net>
Date: Wed, 17 Aug 2022 14:22:02 +0100
[jsinterp] Improve JS language support (#31175)
* operator ??
* operator ?.
* operator **
* accurate operator functions
* `undefined` handling
* object literals {a: 1, "b": expr}
* more tests for weird JS comparisons: see https://github.com/ytdl-org/youtube-dl/issues/31173#issuecomment-1217854397.
Diffstat:
3 files changed, 267 insertions(+), 40 deletions(-)
diff --git a/test/test_jsinterp.py b/test/test_jsinterp.py
@@ -8,7 +8,10 @@ import sys
import unittest
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+import math
+
from youtube_dl.jsinterp import JSInterpreter
+undefined = JSInterpreter.undefined
class TestJSInterpreter(unittest.TestCase):
@@ -48,6 +51,9 @@ class TestJSInterpreter(unittest.TestCase):
jsi = JSInterpreter('function f(){return 1 << 5;}')
self.assertEqual(jsi.call_function('f'), 32)
+ jsi = JSInterpreter('function f(){return 2 ** 5}')
+ self.assertEqual(jsi.call_function('f'), 32)
+
jsi = JSInterpreter('function f(){return 19 & 21;}')
self.assertEqual(jsi.call_function('f'), 17)
@@ -57,6 +63,15 @@ class TestJSInterpreter(unittest.TestCase):
jsi = JSInterpreter('function f(){return []? 2+3: 4;}')
self.assertEqual(jsi.call_function('f'), 5)
+ jsi = JSInterpreter('function f(){return 1 == 2}')
+ self.assertEqual(jsi.call_function('f'), False)
+
+ jsi = JSInterpreter('function f(){return 0 && 1 || 2;}')
+ self.assertEqual(jsi.call_function('f'), 2)
+
+ jsi = JSInterpreter('function f(){return 0 ?? 42;}')
+ self.assertEqual(jsi.call_function('f'), 0)
+
def test_array_access(self):
jsi = JSInterpreter('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}')
self.assertEqual(jsi.call_function('f'), [5, 2, 7])
@@ -203,6 +218,11 @@ class TestJSInterpreter(unittest.TestCase):
''')
self.assertEqual(jsi.call_function('x'), 7)
+ jsi = JSInterpreter('''
+ function x() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }
+ ''')
+ self.assertEqual(jsi.call_function('x'), 5)
+
def test_void(self):
jsi = JSInterpreter('''
function x() { return void 42; }
@@ -215,6 +235,100 @@ class TestJSInterpreter(unittest.TestCase):
''')
self.assertEqual(jsi.call_function('x')([]), 1)
+ def test_null(self):
+ jsi = JSInterpreter('''
+ function x() { return null; }
+ ''')
+ self.assertIs(jsi.call_function('x'), None)
+
+ jsi = JSInterpreter('''
+ function x() { return [null > 0, null < 0, null == 0, null === 0]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, False, False, False])
+
+ jsi = JSInterpreter('''
+ function x() { return [null >= 0, null <= 0]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [True, True])
+
+ def test_undefined(self):
+ jsi = JSInterpreter('''
+ function x() { return undefined === undefined; }
+ ''')
+ self.assertTrue(jsi.call_function('x'))
+
+ jsi = JSInterpreter('''
+ function x() { return undefined; }
+ ''')
+ self.assertIs(jsi.call_function('x'), undefined)
+
+ jsi = JSInterpreter('''
+ function x() { let v; return v; }
+ ''')
+ self.assertIs(jsi.call_function('x'), undefined)
+
+ jsi = JSInterpreter('''
+ function x() { return [undefined === undefined, undefined == undefined, undefined < undefined, undefined > undefined]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [True, True, False, False])
+
+ jsi = JSInterpreter('''
+ function x() { return [undefined === 0, undefined == 0, undefined < 0, undefined > 0]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, False, False, False])
+
+ jsi = JSInterpreter('''
+ function x() { return [undefined >= 0, undefined <= 0]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, False])
+
+ jsi = JSInterpreter('''
+ function x() { return [undefined > null, undefined < null, undefined == null, undefined === null]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, False, True, False])
+
+ jsi = JSInterpreter('''
+ function x() { return [undefined === null, undefined == null, undefined < null, undefined > null]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, True, False, False])
+
+ jsi = JSInterpreter('''
+ function x() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
+ ''')
+ for y in jsi.call_function('x'):
+ self.assertTrue(math.isnan(y))
+
+ jsi = JSInterpreter('''
+ function x() { let v; return v**0; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), 1)
+
+ jsi = JSInterpreter('''
+ function x() { let v; return [v>42, v<=42, v&&42, 42&&v]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [False, False, undefined, undefined])
+
+ jsi = JSInterpreter('function x(){return undefined ?? 42; }')
+ self.assertEqual(jsi.call_function('x'), 42)
+
+ def test_object(self):
+ jsi = JSInterpreter('''
+ function x() { return {}; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), {})
+ jsi = JSInterpreter('''
+ function x() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }
+ ''')
+ self.assertEqual(jsi.call_function('x'), [42, 0])
+ jsi = JSInterpreter('''
+ function x() { let a; return a?.qq; }
+ ''')
+ self.assertIs(jsi.call_function('x'), undefined)
+ jsi = JSInterpreter('''
+ function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
+ ''')
+ self.assertIs(jsi.call_function('x'), undefined)
+
if __name__ == '__main__':
unittest.main()
diff --git a/test/test_youtube_signature.py b/test/test_youtube_signature.py
@@ -102,6 +102,10 @@ _NSIG_TESTS = [
'https://www.youtube.com/s/player/4c3f79c5/player_ias.vflset/en_US/base.js',
'TDCstCG66tEAO5pR9o', 'dbxNtZ14c-yWyw',
),
+ (
+ 'https://www.youtube.com/s/player/c81bbb4a/player_ias.vflset/en_US/base.js',
+ 'gre3EcLurNY2vqp94', 'Z9DfGxWP115WTg',
+ ),
]
diff --git a/youtube_dl/jsinterp.py b/youtube_dl/jsinterp.py
@@ -7,7 +7,6 @@ import operator
import re
from .utils import (
- NO_DEFAULT,
ExtractorError,
js_to_json,
remove_quotes,
@@ -21,6 +20,70 @@ from .compat import (
_NAME_RE = r'[a-zA-Z_$][\w$]*'
+_UNDEFINED = object()
+
+
+def _js_bit_op(op):
+
+ def wrapped(a, b):
+ def zeroise(x):
+ return 0 if x in (None, _UNDEFINED) else x
+ return op(zeroise(a), zeroise(b))
+
+ return wrapped
+
+
+def _js_arith_op(op):
+
+ def wrapped(a, b):
+ if _UNDEFINED in (a, b):
+ return float('nan')
+ return op(a or 0, b or 0)
+
+ return wrapped
+
+
+def _js_div(a, b):
+ if _UNDEFINED in (a, b) or not (a and b):
+ return float('nan')
+ return float('inf') if not b else operator.truediv(a or 0, b)
+
+
+def _js_mod(a, b):
+ if _UNDEFINED in (a, b) or not b:
+ return float('nan')
+ return (a or 0) % b
+
+
+def _js_exp(a, b):
+ if not b:
+ # even 0 ** 0 !!
+ return 1
+ if _UNDEFINED in (a, b):
+ return float('nan')
+ return (a or 0) ** b
+
+
+def _js_eq_op(op):
+
+ def wrapped(a, b):
+ if set((a, b)) <= set((None, _UNDEFINED)):
+ return op(a, a)
+ return op(a, b)
+
+ return wrapped
+
+
+def _js_comp_op(op):
+
+ def wrapped(a, b):
+ if _UNDEFINED in (a, b):
+ return False
+ return op(a or 0, b or 0)
+
+ return wrapped
+
+
# (op, definition) in order of binding priority, tightest first
# avoid dict to maintain order
# definition None => Defined in JSInterpreter._operator
@@ -30,40 +93,38 @@ _DOT_OPERATORS = (
)
_OPERATORS = (
- ('|', operator.or_),
- ('^', operator.xor),
- ('&', operator.and_),
- ('>>', operator.rshift),
- ('<<', operator.lshift),
- ('+', operator.add),
- ('-', operator.sub),
- ('*', operator.mul),
- ('/', operator.truediv),
- ('%', operator.mod),
+ ('>>', _js_bit_op(operator.rshift)),
+ ('<<', _js_bit_op(operator.lshift)),
+ ('+', _js_arith_op(operator.add)),
+ ('-', _js_arith_op(operator.sub)),
+ ('*', _js_arith_op(operator.mul)),
+ ('/', _js_div),
+ ('%', _js_mod),
+ ('**', _js_exp),
)
_COMP_OPERATORS = (
('===', operator.is_),
- ('==', operator.eq),
+ ('==', _js_eq_op(operator.eq)),
('!==', operator.is_not),
- ('!=', operator.ne),
- ('<=', operator.le),
- ('>=', operator.ge),
- ('<', operator.lt),
- ('>', operator.gt),
+ ('!=', _js_eq_op(operator.ne)),
+ ('<=', _js_comp_op(operator.le)),
+ ('>=', _js_comp_op(operator.ge)),
+ ('<', _js_comp_op(operator.lt)),
+ ('>', _js_comp_op(operator.gt)),
)
_LOG_OPERATORS = (
- ('&', operator.and_),
- ('|', operator.or_),
- ('^', operator.xor),
+ ('|', _js_bit_op(operator.or_)),
+ ('^', _js_bit_op(operator.xor)),
+ ('&', _js_bit_op(operator.and_)),
)
_SC_OPERATORS = (
('?', None),
+ ('??', None),
('||', None),
('&&', None),
- # TODO: ('??', None),
)
_OPERATOR_RE = '|'.join(map(lambda x: re.escape(x[0]), _OPERATORS + _LOG_OPERATORS))
@@ -74,7 +135,7 @@ _QUOTES = '\'"'
def _ternary(cndn, if_true=True, if_false=False):
"""Simulate JS's ternary operator (cndn?if_true:if_false)"""
- if cndn in (False, None, 0, ''):
+ if cndn in (False, None, 0, '', _UNDEFINED):
return if_false
try:
if math.isnan(cndn): # NB: NaN cannot be checked by membership
@@ -95,6 +156,12 @@ class JS_Continue(ExtractorError):
class LocalNameSpace(ChainMap):
+ def __getitem__(self, key):
+ try:
+ return super(LocalNameSpace, self).__getitem__(key)
+ except KeyError:
+ return _UNDEFINED
+
def __setitem__(self, key, value):
for scope in self.maps:
if key in scope:
@@ -105,6 +172,13 @@ class LocalNameSpace(ChainMap):
def __delitem__(self, key):
raise NotImplementedError('Deleting is not supported')
+ def __contains__(self, key):
+ try:
+ super(LocalNameSpace, self).__getitem__(key)
+ return True
+ except KeyError:
+ return False
+
def __repr__(self):
return 'LocalNameSpace%s' % (self.maps, )
@@ -112,6 +186,8 @@ class LocalNameSpace(ChainMap):
class JSInterpreter(object):
__named_object_counter = 0
+ undefined = _UNDEFINED
+
def __init__(self, code, objects=None):
self.code, self._functions = code, {}
self._objects = {} if objects is None else objects
@@ -185,12 +261,16 @@ class JSInterpreter(object):
@staticmethod
def _all_operators():
return itertools.chain(
+ # Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
_SC_OPERATORS, _LOG_OPERATORS, _COMP_OPERATORS, _OPERATORS)
def _operator(self, op, left_val, right_expr, expr, local_vars, allow_recursion):
if op in ('||', '&&'):
if (op == '&&') ^ _ternary(left_val):
return left_val # short circuiting
+ elif op == '??':
+ if left_val not in (None, self.undefined):
+ return left_val
elif op == '?':
right_expr = _ternary(left_val, *self._separate(right_expr, ':', 1))
@@ -204,12 +284,14 @@ class JSInterpreter(object):
except Exception as e:
raise self.Exception('Failed to evaluate {left_val!r} {op} {right_val!r}'.format(**locals()), expr, cause=e)
- def _index(self, obj, idx):
+ def _index(self, obj, idx, allow_undefined=False):
if idx == 'length':
return len(obj)
try:
return obj[int(idx)] if isinstance(obj, list) else obj[idx]
except Exception as e:
+ if allow_undefined:
+ return self.undefined
raise self.Exception('Cannot get index {idx}'.format(**locals()), expr=repr(obj), cause=e)
def _dump(self, obj, namespace):
@@ -249,8 +331,8 @@ class JSInterpreter(object):
obj = expr[4:]
if obj.startswith('Date('):
left, right = self._separate_at_paren(obj[4:], ')')
- left = self.interpret_expression(left, local_vars, allow_recursion)
- expr = unified_timestamp(left, False)
+ expr = unified_timestamp(
+ self.interpret_expression(left, local_vars, allow_recursion), False)
if not expr:
raise self.Exception('Failed to parse date {left!r}'.format(**locals()), expr=expr)
expr = self._dump(int(expr * 1000), local_vars) + right
@@ -263,6 +345,14 @@ class JSInterpreter(object):
if expr.startswith('{'):
inner, outer = self._separate_at_paren(expr, '}')
+ # try for object expression
+ sub_expressions = [list(self._separate(sub_expr.strip(), ':', 1)) for sub_expr in self._separate(inner)]
+ if all(len(sub_expr) == 2 for sub_expr in sub_expressions):
+ return dict(
+ (key_expr if re.match(_NAME_RE, key_expr) else key_expr,
+ self.interpret_expression(val_expr, local_vars, allow_recursion))
+ for key_expr, val_expr in sub_expressions), should_return
+ # or statement list
inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
if not outer or should_abort:
return inner, should_abort or should_return
@@ -387,13 +477,13 @@ class JSInterpreter(object):
(?P<assign>
(?P<out>{_NAME_RE})(?:\[(?P<index>[^\]]+?)\])?\s*
(?P<op>{_OPERATOR_RE})?
- =(?P<expr>.*)$
+ =(?!=)(?P<expr>.*)$
)|(?P<return>
(?!if|return|true|false|null|undefined)(?P<name>{_NAME_RE})$
)|(?P<indexing>
(?P<in>{_NAME_RE})\[(?P<idx>.+)\]$
)|(?P<attribute>
- (?P<var>{_NAME_RE})(?:\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
+ (?P<var>{_NAME_RE})(?:(?P<nullish>\?)?\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
)|(?P<function>
(?P<fname>{_NAME_RE})\((?P<args>.*)\)$
)'''.format(**globals()), expr)
@@ -405,7 +495,7 @@ class JSInterpreter(object):
local_vars[m.group('out')] = self._operator(
m.group('op'), left_val, m.group('expr'), expr, local_vars, allow_recursion)
return local_vars[m.group('out')], should_return
- elif left_val is None:
+ elif left_val in (None, self.undefined):
raise self.Exception('Cannot index undefined variable ' + m.group('out'), expr=expr)
idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
@@ -424,6 +514,9 @@ class JSInterpreter(object):
elif expr == 'continue':
raise JS_Continue()
+ elif expr == 'undefined':
+ return self.undefined, should_return
+
elif md.get('return'):
return local_vars[m.group('name')], should_return
@@ -441,7 +534,9 @@ class JSInterpreter(object):
for op, _ in self._all_operators():
# hackety: </> have higher priority than <</>>, but don't confuse them
- skip_delim = (op + op) if op in ('<', '>') else None
+ skip_delim = (op + op) if op in '<>*?' else None
+ if op == '?':
+ skip_delim = (skip_delim, '?.')
separated = list(self._separate(expr, op, skip_delims=skip_delim))
if len(separated) < 2:
continue
@@ -451,12 +546,10 @@ class JSInterpreter(object):
right_expr = '-' + right_expr
separated.pop()
left_val = self.interpret_expression(op.join(separated), local_vars, allow_recursion)
- return self._operator(op, 0 if left_val is None else left_val,
- right_expr, expr, local_vars, allow_recursion), should_return
+ return self._operator(op, left_val, right_expr, expr, local_vars, allow_recursion), should_return
if md.get('attribute'):
- variable = m.group('var')
- member = m.group('member')
+ variable, member, nullish = m.group('var', 'member', 'nullish')
if not member:
member = self.interpret_expression(m.group('member2'), local_vars, allow_recursion)
arg_str = expr[m.end():]
@@ -477,15 +570,24 @@ class JSInterpreter(object):
'String': compat_str,
'Math': float,
}
- obj = local_vars.get(variable, types.get(variable, NO_DEFAULT))
- if obj is NO_DEFAULT:
- if variable not in self._objects:
- self._objects[variable] = self.extract_object(variable)
- obj = self._objects[variable]
+ obj = local_vars.get(variable)
+ if obj in (self.undefined, None):
+ obj = types.get(variable, self.undefined)
+ if obj is self.undefined:
+ try:
+ if variable not in self._objects:
+ self._objects[variable] = self.extract_object(variable)
+ obj = self._objects[variable]
+ except self.Exception:
+ if not nullish:
+ raise
+
+ if nullish and obj is self.undefined:
+ return self.undefined
# Member access
if arg_str is None:
- return self._index(obj, member)
+ return self._index(obj, member, nullish)
# Function call
argvals = [
@@ -660,7 +762,14 @@ class JSInterpreter(object):
def build_arglist(cls, arg_text):
if not arg_text:
return []
- return list(filter(None, (x.strip() or None for x in cls._separate(arg_text))))
+
+ def valid_arg(y):
+ y = y.strip()
+ if not y:
+ raise cls.Exception('Missing arg in "%s"' % (arg_text, ))
+ return y
+
+ return [valid_arg(x) for x in cls._separate(arg_text)]
def build_function(self, argnames, code, *global_stack):
global_stack = list(global_stack) or [{}]
