diff options
Diffstat (limited to 'youtube_dl/jsinterp.py')
| -rw-r--r-- | youtube_dl/jsinterp.py | 109 |
1 files changed, 87 insertions, 22 deletions
diff --git a/youtube_dl/jsinterp.py b/youtube_dl/jsinterp.py index 449482d3c..c40cd376d 100644 --- a/youtube_dl/jsinterp.py +++ b/youtube_dl/jsinterp.py @@ -1,5 +1,6 @@ from __future__ import unicode_literals +import json import re from .utils import ( @@ -11,6 +12,7 @@ class JSInterpreter(object): def __init__(self, code): self.code = code self._functions = {} + self._objects = {} def interpret_statement(self, stmt, local_vars, allow_recursion=20): if allow_recursion < 0: @@ -39,8 +41,9 @@ class JSInterpreter(object): assign = lambda v: v expr = stmt[len('return '):] else: - raise ExtractorError( - 'Cannot determine left side of statement in %r' % stmt) + # Try interpreting it as an expression + expr = stmt + assign = lambda v: v v = self.interpret_expression(expr, local_vars, allow_recursion) return assign(v) @@ -52,23 +55,63 @@ class JSInterpreter(object): if expr.isalpha(): return local_vars[expr] - m = re.match(r'^(?P<in>[a-z]+)\.(?P<member>.*)$', expr) + try: + return json.loads(expr) + except ValueError: + pass + + m = re.match( + r'^(?P<var>[a-zA-Z0-9_]+)\.(?P<member>[^(]+)(?:\(+(?P<args>[^()]*)\))?$', + expr) if m: + variable = m.group('var') member = m.group('member') - val = local_vars[m.group('in')] - if member == 'split("")': - return list(val) - if member == 'join("")': - return u''.join(val) - if member == 'length': - return len(val) - if member == 'reverse()': - return val[::-1] - slice_m = re.match(r'slice\((?P<idx>.*)\)', member) - if slice_m: - idx = self.interpret_expression( - slice_m.group('idx'), local_vars, allow_recursion - 1) - return val[idx:] + arg_str = m.group('args') + + if variable in local_vars: + obj = local_vars[variable] + else: + if variable not in self._objects: + self._objects[variable] = self.extract_object(variable) + obj = self._objects[variable] + + if arg_str is None: + # Member access + if member == 'length': + return len(obj) + return obj[member] + + assert expr.endswith(')') + # Function call + if arg_str == '': + argvals = tuple() + else: + argvals = tuple([ + self.interpret_expression(v, local_vars, allow_recursion) + for v in arg_str.split(',')]) + + if member == 'split': + assert argvals == ('',) + return list(obj) + if member == 'join': + assert len(argvals) == 1 + return argvals[0].join(obj) + if member == 'reverse': + assert len(argvals) == 0 + obj.reverse() + return obj + if member == 'slice': + assert len(argvals) == 1 + return obj[argvals[0]:] + if member == 'splice': + assert isinstance(obj, list) + index, howMany = argvals + res = [] + for i in range(index, min(index + howMany, len(obj))): + res.append(obj.pop(index)) + return res + + return obj[member](argvals) m = re.match( r'^(?P<in>[a-z]+)\[(?P<idx>.+)\]$', expr) @@ -90,16 +133,36 @@ class JSInterpreter(object): r'^(?P<func>[a-zA-Z$]+)\((?P<args>[a-z0-9,]+)\)$', expr) if m: fname = m.group('func') + argvals = tuple([ + int(v) if v.isdigit() else local_vars[v] + for v in m.group('args').split(',')]) if fname not in self._functions: self._functions[fname] = self.extract_function(fname) - argvals = [int(v) if v.isdigit() else local_vars[v] - for v in m.group('args').split(',')] return self._functions[fname](argvals) raise ExtractorError('Unsupported JS expression %r' % expr) + def extract_object(self, objname): + obj = {} + obj_m = re.search( + (r'(?:var\s+)?%s\s*=\s*\{' % re.escape(objname)) + + r'\s*(?P<fields>([a-zA-Z$0-9]+\s*:\s*function\(.*?\)\s*\{.*?\})*)' + + r'\}\s*;', + self.code) + fields = obj_m.group('fields') + # Currently, it only supports function definitions + fields_m = re.finditer( + r'(?P<key>[a-zA-Z$0-9]+)\s*:\s*function' + r'\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}', + fields) + for f in fields_m: + argnames = f.group('args').split(',') + obj[f.group('key')] = self.build_function(argnames, f.group('code')) + + return obj + def extract_function(self, funcname): func_m = re.search( - (r'(?:function %s|%s\s*=\s*function)' % ( + (r'(?:function %s|[{;]%s\s*=\s*function)' % ( re.escape(funcname), re.escape(funcname))) + r'\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}', self.code) @@ -107,10 +170,12 @@ class JSInterpreter(object): raise ExtractorError('Could not find JS function %r' % funcname) argnames = func_m.group('args').split(',') + return self.build_function(argnames, func_m.group('code')) + + def build_function(self, argnames, code): def resf(args): local_vars = dict(zip(argnames, args)) - for stmt in func_m.group('code').split(';'): + for stmt in code.split(';'): res = self.interpret_statement(stmt, local_vars) return res return resf - |