import collections
import contextlib
+import itertools
import json
+import math
import operator
import re
-from .utils import ExtractorError, remove_quotes, truncate_string
+from .utils import (
+ NO_DEFAULT,
+ ExtractorError,
+ js_to_json,
+ remove_quotes,
+ truncate_string,
+ unified_timestamp,
+ write_string,
+)
_NAME_RE = r'[a-zA-Z_$][\w$]*'
-_OPERATORS = {
+_OPERATORS = { # None => Defined in JSInterpreter._operator
+ '?': None,
+
+ '||': None,
+ '&&': None,
+ '&': operator.and_,
'|': operator.or_,
'^': operator.xor,
- '&': operator.and_,
+
+ # FIXME: This should actually be below comparision
'>>': operator.rshift,
'<<': operator.lshift,
- '-': operator.sub,
+
+ '<=': operator.le,
+ '>=': operator.ge,
+ '<': operator.lt,
+ '>': operator.gt,
+
'+': operator.add,
- '%': operator.mod,
- '/': operator.truediv,
+ '-': operator.sub,
+
'*': operator.mul,
+ '/': operator.truediv,
+ '%': operator.mod,
}
_MATCHING_PARENS = dict(zip('({[', ')}]'))
_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, ''):
+ return if_false
+ with contextlib.suppress(TypeError):
+ if math.isnan(cndn): # NB: NaN cannot be checked by membership
+ return if_false
+ return if_true
+
+
class JS_Break(ExtractorError):
def __init__(self):
ExtractorError.__init__(self, 'Invalid break')
raise NotImplementedError('Deleting is not supported')
+class Debugger:
+ import sys
+ ENABLED = 'pytest' in sys.modules
+
+ @staticmethod
+ def write(*args, level=100):
+ write_string(f'[debug] JS: {" " * (100 - level)}'
+ f'{" ".join(truncate_string(str(x), 50, 50) for x in args)}\n')
+
+ @classmethod
+ def wrap_interpreter(cls, f):
+ def interpret_statement(self, stmt, local_vars, allow_recursion, *args, **kwargs):
+ if cls.ENABLED and stmt.strip():
+ cls.write(stmt, level=allow_recursion)
+ ret, should_ret = f(self, stmt, local_vars, allow_recursion, *args, **kwargs)
+ if cls.ENABLED and stmt.strip():
+ cls.write(['->', '=>'][should_ret], repr(ret), '<-|', stmt, level=allow_recursion)
+ return ret, should_ret
+ return interpret_statement
+
+
class JSInterpreter:
__named_object_counter = 0
class Exception(ExtractorError):
def __init__(self, msg, expr=None, *args, **kwargs):
if expr is not None:
- msg += f' in: {truncate_string(expr, 50, 50)}'
+ msg = f'{msg.rstrip()} in: {truncate_string(expr, 50, 50)}'
super().__init__(msg, *args, **kwargs)
def _named_object(self, namespace, obj):
start, splits, pos, delim_len = 0, 0, 0, len(delim) - 1
in_quote, escaping = None, False
for idx, char in enumerate(expr):
- if char in _MATCHING_PARENS:
+ if not in_quote and char in _MATCHING_PARENS:
counters[_MATCHING_PARENS[char]] += 1
- elif char in counters:
+ elif not in_quote and char in counters:
counters[char] -= 1
elif not escaping and char in _QUOTES and in_quote in (char, None):
in_quote = None if in_quote else char
raise cls.Exception(f'No terminating paren {delim}', expr)
return separated[0][1:].strip(), separated[1].strip()
+ 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 == '?':
+ right_expr = _ternary(left_val, *self._separate(right_expr, ':', 1))
+
+ right_val = self.interpret_expression(right_expr, local_vars, allow_recursion)
+ if not _OPERATORS.get(op):
+ return right_val
+
+ try:
+ return _OPERATORS[op](left_val, right_val)
+ except Exception as e:
+ raise self.Exception(f'Failed to evaluate {left_val!r} {op} {right_val!r}', expr, cause=e)
+
+ def _index(self, obj, idx):
+ if idx == 'length':
+ return len(obj)
+ try:
+ return obj[int(idx)] if isinstance(obj, list) else obj[idx]
+ except Exception as e:
+ raise self.Exception(f'Cannot get index {idx}', repr(obj), cause=e)
+
+ def _dump(self, obj, namespace):
+ try:
+ return json.dumps(obj)
+ except TypeError:
+ return self._named_object(namespace, obj)
+
+ @Debugger.wrap_interpreter
def interpret_statement(self, stmt, local_vars, allow_recursion=100):
if allow_recursion < 0:
raise self.Exception('Recursion limit reached')
+ allow_recursion -= 1
- should_abort = False
+ should_return = False
sub_statements = list(self._separate(stmt, ';')) or ['']
- stmt = sub_statements.pop().lstrip()
+ expr = stmt = sub_statements.pop().strip()
for sub_stmt in sub_statements:
- ret, should_abort = self.interpret_statement(sub_stmt, local_vars, allow_recursion - 1)
- if should_abort:
- return ret, should_abort
+ ret, should_return = self.interpret_statement(sub_stmt, local_vars, allow_recursion)
+ if should_return:
+ return ret, should_return
m = re.match(r'(?P<var>var\s)|return(?:\s+|$)', stmt)
- if not m: # Try interpreting it as an expression
- expr = stmt
- elif m.group('var'):
- expr = stmt[len(m.group(0)):]
- else:
- expr = stmt[len(m.group(0)):]
- should_abort = True
-
- return self.interpret_expression(expr, local_vars, allow_recursion), should_abort
-
- def interpret_expression(self, expr, local_vars, allow_recursion):
- expr = expr.strip()
+ if m:
+ expr = stmt[len(m.group(0)):].strip()
+ should_return = not m.group('var')
if not expr:
- return None
+ return None, should_return
+
+ if expr[0] in _QUOTES:
+ inner, outer = self._separate(expr, expr[0], 1)
+ inner = json.loads(js_to_json(f'{inner}{expr[0]}', strict=True))
+ if not outer:
+ return inner, should_return
+ expr = self._named_object(local_vars, inner) + outer
+
+ if expr.startswith('new '):
+ obj = expr[4:]
+ if obj.startswith('Date('):
+ left, right = self._separate_at_paren(obj[4:], ')')
+ expr = unified_timestamp(left[1:-1], False)
+ if not expr:
+ raise self.Exception(f'Failed to parse date {left!r}', expr)
+ expr = self._dump(int(expr * 1000), local_vars) + right
+ else:
+ raise self.Exception(f'Unsupported object {obj}', expr)
if expr.startswith('{'):
inner, outer = self._separate_at_paren(expr, '}')
- inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion - 1)
+ inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
if not outer or should_abort:
- return inner
+ return inner, should_abort or should_return
else:
- expr = json.dumps(inner) + outer
+ expr = self._dump(inner, local_vars) + outer
if expr.startswith('('):
inner, outer = self._separate_at_paren(expr, ')')
- inner = self.interpret_expression(inner, local_vars, allow_recursion)
- if not outer:
- return inner
+ inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
+ if not outer or should_abort:
+ return inner, should_abort or should_return
else:
- expr = json.dumps(inner) + outer
+ expr = self._dump(inner, local_vars) + outer
if expr.startswith('['):
inner, outer = self._separate_at_paren(expr, ']')
for item in self._separate(inner)])
expr = name + outer
- m = re.match(r'(?P<try>try)\s*|(?:(?P<catch>catch)|(?P<for>for)|(?P<switch>switch))\s*\(', expr)
+ m = re.match(r'(?P<try>try|finally)\s*|(?:(?P<catch>catch)|(?P<for>for)|(?P<switch>switch))\s*\(', expr)
if m and m.group('try'):
if expr[m.end()] == '{':
try_expr, expr = self._separate_at_paren(expr[m.end():], '}')
else:
try_expr, expr = expr[m.end() - 1:], ''
- ret, should_abort = self.interpret_statement(try_expr, local_vars, allow_recursion - 1)
+ ret, should_abort = self.interpret_statement(try_expr, local_vars, allow_recursion)
if should_abort:
- return ret
- return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
+ return ret, True
+ ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
+ return ret, should_abort or should_return
elif m and m.group('catch'):
# We ignore the catch block
_, expr = self._separate_at_paren(expr, '}')
- return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
+ ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
+ return ret, should_abort or should_return
elif m and m.group('for'):
constructor, remaining = self._separate_at_paren(expr[m.end() - 1:], ')')
else:
body, expr = remaining, ''
start, cndn, increment = self._separate(constructor, ';')
- if self.interpret_statement(start, local_vars, allow_recursion - 1)[1]:
- raise self.Exception('Premature return in the initialization of a for loop', constructor)
+ self.interpret_expression(start, local_vars, allow_recursion)
while True:
- if not self.interpret_expression(cndn, local_vars, allow_recursion):
+ if not _ternary(self.interpret_expression(cndn, local_vars, allow_recursion)):
break
try:
- ret, should_abort = self.interpret_statement(body, local_vars, allow_recursion - 1)
+ ret, should_abort = self.interpret_statement(body, local_vars, allow_recursion)
if should_abort:
- return ret
+ return ret, True
except JS_Break:
break
except JS_Continue:
pass
- if self.interpret_statement(increment, local_vars, allow_recursion - 1)[1]:
- raise self.Exception('Premature return in the initialization of a for loop', constructor)
- return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
+ self.interpret_expression(increment, local_vars, allow_recursion)
+ ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
+ return ret, should_abort or should_return
elif m and m.group('switch'):
switch_val, remaining = self._separate_at_paren(expr[m.end() - 1:], ')')
if not matched:
continue
try:
- ret, should_abort = self.interpret_statement(stmt, local_vars, allow_recursion - 1)
+ ret, should_abort = self.interpret_statement(stmt, local_vars, allow_recursion)
if should_abort:
return ret
except JS_Break:
break
if matched:
break
- return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
+ ret, should_abort = self.interpret_statement(expr, local_vars, allow_recursion)
+ return ret, should_abort or should_return
# Comma separated statements
sub_expressions = list(self._separate(expr))
expr = sub_expressions.pop().strip() if sub_expressions else ''
for sub_expr in sub_expressions:
- self.interpret_expression(sub_expr, local_vars, allow_recursion)
+ ret, should_abort = self.interpret_statement(sub_expr, local_vars, allow_recursion)
+ if should_abort:
+ return ret, True
for m in re.finditer(rf'''(?x)
(?P<pre_sign>\+\+|--)(?P<var1>{_NAME_RE})|
local_vars[var] += 1 if sign[0] == '+' else -1
if m.group('pre_sign'):
ret = local_vars[var]
- expr = expr[:start] + json.dumps(ret) + expr[end:]
+ expr = expr[:start] + self._dump(ret, local_vars) + expr[end:]
if not expr:
- return None
+ return None, should_return
m = re.match(fr'''(?x)
(?P<assign>
(?P<op>{"|".join(map(re.escape, _OPERATORS))})?
=(?P<expr>.*)$
)|(?P<return>
- (?!if|return|true|false|null)(?P<name>{_NAME_RE})$
+ (?!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<function>
- (?P<fname>{_NAME_RE})\((?P<args>[\w$,]*)\)$
+ (?P<fname>{_NAME_RE})\((?P<args>.*)\)$
)''', expr)
if m and m.group('assign'):
- if not m.group('op'):
- opfunc = lambda curr, right: right
- else:
- opfunc = _OPERATORS[m.group('op')]
- right_val = self.interpret_expression(m.group('expr'), local_vars, allow_recursion)
left_val = local_vars.get(m.group('out'))
if not m.group('index'):
- local_vars[m.group('out')] = opfunc(left_val, right_val)
- return local_vars[m.group('out')]
+ 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:
raise self.Exception(f'Cannot index undefined variable {m.group("out")}', expr)
idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
- if not isinstance(idx, int):
+ if not isinstance(idx, (int, float)):
raise self.Exception(f'List index {idx} must be integer', expr)
- left_val[idx] = opfunc(left_val[idx], right_val)
- return left_val[idx]
+ idx = int(idx)
+ left_val[idx] = self._operator(
+ m.group('op'), left_val[idx], m.group('expr'), expr, local_vars, allow_recursion)
+ return left_val[idx], should_return
elif expr.isdigit():
- return int(expr)
+ return int(expr), should_return
elif expr == 'break':
raise JS_Break()
raise JS_Continue()
elif m and m.group('return'):
- return local_vars[m.group('name')]
+ return local_vars[m.group('name')], should_return
with contextlib.suppress(ValueError):
- return json.loads(expr)
+ return json.loads(js_to_json(expr, strict=True)), should_return
if m and m.group('indexing'):
val = local_vars[m.group('in')]
idx = self.interpret_expression(m.group('idx'), local_vars, allow_recursion)
- return val[idx]
+ return self._index(val, idx), should_return
- for op, opfunc in _OPERATORS.items():
+ for op in _OPERATORS:
separated = list(self._separate(expr, op))
if len(separated) < 2:
continue
- right_val = separated.pop()
- left_val = op.join(separated)
- left_val, should_abort = self.interpret_statement(
- left_val, local_vars, allow_recursion - 1)
- if should_abort:
- raise self.Exception(f'Premature left-side return of {op}', expr)
- right_val, should_abort = self.interpret_statement(
- right_val, local_vars, allow_recursion - 1)
- if should_abort:
- raise self.Exception(f'Premature right-side return of {op}', expr)
- return opfunc(left_val or 0, right_val)
+ right_expr = separated.pop()
+ while op == '-' and len(separated) > 1 and not separated[-1].strip():
+ right_expr = f'-{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
if m and m.group('attribute'):
variable = m.group('var')
- member = remove_quotes(m.group('member') or m.group('member2'))
+ member = m.group('member')
+ if not member:
+ member = self.interpret_expression(m.group('member2'), local_vars, allow_recursion)
arg_str = expr[m.end():]
if arg_str.startswith('('):
arg_str, remaining = self._separate_at_paren(arg_str, ')')
raise self.Exception(f'{member} {msg}', expr)
def eval_method():
- if variable == 'String':
- obj = str
- elif variable in local_vars:
- obj = local_vars[variable]
- else:
+ if (variable, member) == ('console', 'debug'):
+ if Debugger.ENABLED:
+ Debugger.write(self.interpret_expression(f'[{arg_str}]', local_vars, allow_recursion))
+ return
+
+ types = {
+ 'String': 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]
# Member access
if arg_str is None:
- if member == 'length':
- return len(obj)
- return obj[member]
+ return self._index(obj, member)
# Function call
argvals = [
if member == 'fromCharCode':
assertion(argvals, 'takes one or more arguments')
return ''.join(map(chr, argvals))
- raise self.Exception(f'Unsupported string method {member}', expr)
+ raise self.Exception(f'Unsupported String method {member}', expr)
+ elif obj == float:
+ if member == 'pow':
+ assertion(len(argvals) == 2, 'takes two arguments')
+ return argvals[0] ** argvals[1]
+ raise self.Exception(f'Unsupported Math method {member}', expr)
if member == 'split':
assertion(argvals, 'takes one or more arguments')
- assertion(argvals == [''], 'with arguments is not implemented')
- return list(obj)
+ assertion(len(argvals) == 1, 'with limit argument is not implemented')
+ return obj.split(argvals[0]) if argvals[0] else list(obj)
elif member == 'join':
assertion(isinstance(obj, list), 'must be applied on a list')
assertion(len(argvals) == 1, 'takes exactly one argument')
assertion(argvals, 'takes one or more arguments')
assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
f, this = (argvals + [''])[:2]
- return [f((item, idx, obj), this=this) for idx, item in enumerate(obj)]
+ return [f((item, idx, obj), {'this': this}, allow_recursion) for idx, item in enumerate(obj)]
elif member == 'indexOf':
assertion(argvals, 'takes one or more arguments')
assertion(len(argvals) <= 2, 'takes at-most 2 arguments')
except ValueError:
return -1
- return obj[int(member) if isinstance(obj, list) else member](argvals)
+ idx = int(member) if isinstance(obj, list) else member
+ return obj[idx](argvals, allow_recursion=allow_recursion)
if remaining:
- return self.interpret_expression(
+ ret, should_abort = self.interpret_statement(
self._named_object(local_vars, eval_method()) + remaining,
local_vars, allow_recursion)
+ return ret, should_return or should_abort
else:
- return eval_method()
+ return eval_method(), should_return
elif m and m.group('function'):
fname = m.group('fname')
- argvals = tuple(
- int(v) if v.isdigit() else local_vars[v]
- for v in self._separate(m.group('args')))
+ argvals = [self.interpret_expression(v, local_vars, allow_recursion)
+ for v in self._separate(m.group('args'))]
if fname in local_vars:
- return local_vars[fname](argvals)
+ return local_vars[fname](argvals, allow_recursion=allow_recursion), should_return
elif fname not in self._functions:
self._functions[fname] = self.extract_function(fname)
- return self._functions[fname](argvals)
+ return self._functions[fname](argvals, allow_recursion=allow_recursion), should_return
+
+ raise self.Exception(
+ f'Unsupported JS expression {truncate_string(expr, 20, 20) if expr != stmt else ""}', stmt)
- raise self.Exception('Unsupported JS expression', expr)
+ def interpret_expression(self, expr, local_vars, allow_recursion):
+ ret, should_return = self.interpret_statement(expr, local_vars, allow_recursion)
+ if should_return:
+ raise self.Exception('Cannot return from an expression', expr)
+ return ret
def extract_object(self, objname):
_FUNC_NAME_RE = r'''(?:[a-zA-Z$0-9]+|"[a-zA-Z$0-9]+"|'[a-zA-Z$0-9]+')'''
}\s*;
''' % (re.escape(objname), _FUNC_NAME_RE),
self.code)
+ if not obj_m:
+ raise self.Exception(f'Could not find object {objname}')
fields = obj_m.group('fields')
# Currently, it only supports function definitions
fields_m = re.finditer(
def extract_function_code(self, funcname):
""" @returns argnames, code """
func_m = re.search(
- r'''(?x)
+ r'''(?xs)
(?:
function\s+%(name)s|
[{;,]\s*%(name)s\s*=\s*function|
var\s+%(name)s\s*=\s*function
)\s*
\((?P<args>[^)]*)\)\s*
- (?P<code>{(?:(?!};)[^"]|"([^"]|\\")*")+})''' % {'name': re.escape(funcname)},
+ (?P<code>{.+})''' % {'name': re.escape(funcname)},
self.code)
- code, _ = self._separate_at_paren(func_m.group('code'), '}') # refine the match
+ code, _ = self._separate_at_paren(func_m.group('code'), '}')
if func_m is None:
raise self.Exception(f'Could not find JS function "{funcname}"')
- return func_m.group('args').split(','), code
+ return [x.strip() for x in func_m.group('args').split(',')], code
def extract_function(self, funcname):
return self.extract_function_from_code(*self.extract_function_code(funcname))
def build_function(self, argnames, code, *global_stack):
global_stack = list(global_stack) or [{}]
+ argnames = tuple(argnames)
- def resf(args, **kwargs):
+ def resf(args, kwargs={}, allow_recursion=100):
global_stack[0].update({
- **dict(zip(argnames, args)),
+ **dict(itertools.zip_longest(argnames, args, fillvalue=None)),
**kwargs
})
var_stack = LocalNameSpace(*global_stack)
- for stmt in self._separate(code.replace('\n', ''), ';'):
- ret, should_abort = self.interpret_statement(stmt, var_stack)
- if should_abort:
- break
- return ret
+ ret, should_abort = self.interpret_statement(code.replace('\n', ''), var_stack, allow_recursion - 1)
+ if should_abort:
+ return ret
return resf
projects / yt-dlp.git / commitdiff
