[youtube] Move JavaScript interpreter into its own module
This commit is contained in:
Philipp Hagemeister
parent
62fec3b2ff
commit
2b25cb5d76
2 changed files with 117 additions and 106 deletions
|
|
@ -14,6 +14,7 @@ import zlib
|
|||
|
||||
from .common import InfoExtractor, SearchInfoExtractor
|
||||
from .subtitles import SubtitlesInfoExtractor
|
||||
from ..jsinterp import JSInterpreter
|
||||
from ..utils import (
|
||||
compat_chr,
|
||||
compat_parse_qs,
|
||||
|
|
@ -438,113 +439,10 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
|
|||
def _parse_sig_js(self, jscode):
|
||||
funcname = self._search_regex(
|
||||
r'signature=([a-zA-Z]+)', jscode,
|
||||
u'Initial JS player signature function name')
|
||||
u'Initial JS player signature function name')
|
||||
|
||||
functions = {}
|
||||
|
||||
def argidx(varname):
|
||||
return string.lowercase.index(varname)
|
||||
|
||||
def interpret_statement(stmt, local_vars, allow_recursion=20):
|
||||
if allow_recursion < 0:
|
||||
raise ExtractorError(u'Recursion limit reached')
|
||||
|
||||
if stmt.startswith(u'var '):
|
||||
stmt = stmt[len(u'var '):]
|
||||
ass_m = re.match(r'^(?P<out>[a-z]+)(?:\[(?P<index>[^\]]+)\])?' +
|
||||
r'=(?P<expr>.*)$', stmt)
|
||||
if ass_m:
|
||||
if ass_m.groupdict().get('index'):
|
||||
def assign(val):
|
||||
lvar = local_vars[ass_m.group('out')]
|
||||
idx = interpret_expression(ass_m.group('index'),
|
||||
local_vars, allow_recursion)
|
||||
assert isinstance(idx, int)
|
||||
lvar[idx] = val
|
||||
return val
|
||||
expr = ass_m.group('expr')
|
||||
else:
|
||||
def assign(val):
|
||||
local_vars[ass_m.group('out')] = val
|
||||
return val
|
||||
expr = ass_m.group('expr')
|
||||
elif stmt.startswith(u'return '):
|
||||
assign = lambda v: v
|
||||
expr = stmt[len(u'return '):]
|
||||
else:
|
||||
raise ExtractorError(
|
||||
u'Cannot determine left side of statement in %r' % stmt)
|
||||
|
||||
v = interpret_expression(expr, local_vars, allow_recursion)
|
||||
return assign(v)
|
||||
|
||||
def interpret_expression(expr, local_vars, allow_recursion):
|
||||
if expr.isdigit():
|
||||
return int(expr)
|
||||
|
||||
if expr.isalpha():
|
||||
return local_vars[expr]
|
||||
|
||||
m = re.match(r'^(?P<in>[a-z]+)\.(?P<member>.*)$', expr)
|
||||
if m:
|
||||
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 = interpret_expression(
|
||||
slice_m.group('idx'), local_vars, allow_recursion-1)
|
||||
return val[idx:]
|
||||
|
||||
m = re.match(
|
||||
r'^(?P<in>[a-z]+)\[(?P<idx>.+)\]$', expr)
|
||||
if m:
|
||||
val = local_vars[m.group('in')]
|
||||
idx = interpret_expression(m.group('idx'), local_vars,
|
||||
allow_recursion-1)
|
||||
return val[idx]
|
||||
|
||||
m = re.match(r'^(?P<a>.+?)(?P<op>[%])(?P<b>.+?)$', expr)
|
||||
if m:
|
||||
a = interpret_expression(m.group('a'),
|
||||
local_vars, allow_recursion)
|
||||
b = interpret_expression(m.group('b'),
|
||||
local_vars, allow_recursion)
|
||||
return a % b
|
||||
|
||||
m = re.match(
|
||||
r'^(?P<func>[a-zA-Z$]+)\((?P<args>[a-z0-9,]+)\)$', expr)
|
||||
if m:
|
||||
fname = m.group('func')
|
||||
if fname not in functions:
|
||||
functions[fname] = extract_function(fname)
|
||||
argvals = [int(v) if v.isdigit() else local_vars[v]
|
||||
for v in m.group('args').split(',')]
|
||||
return functions[fname](argvals)
|
||||
raise ExtractorError(u'Unsupported JS expression %r' % expr)
|
||||
|
||||
def extract_function(funcname):
|
||||
func_m = re.search(
|
||||
r'function ' + re.escape(funcname) +
|
||||
r'\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}',
|
||||
jscode)
|
||||
argnames = func_m.group('args').split(',')
|
||||
|
||||
def resf(args):
|
||||
local_vars = dict(zip(argnames, args))
|
||||
for stmt in func_m.group('code').split(';'):
|
||||
res = interpret_statement(stmt, local_vars)
|
||||
return res
|
||||
return resf
|
||||
|
||||
initial_function = extract_function(funcname)
|
||||
jsi = JSInterpreter(jscode)
|
||||
initial_function = jsi.extract_function(funcname)
|
||||
return lambda s: initial_function([s])
|
||||
|
||||
def _parse_sig_swf(self, file_contents):
|
||||
|
|
|
|||
113
youtube_dl/jsinterp.py
Normal file
113
youtube_dl/jsinterp.py
Normal file
|
|
@ -0,0 +1,113 @@
|
|||
from __future__ import unicode_literals
|
||||
|
||||
import re
|
||||
|
||||
from .utils import (
|
||||
ExtractorError,
|
||||
)
|
||||
|
||||
|
||||
class JSInterpreter(object):
|
||||
def __init__(self, code):
|
||||
self.code = code
|
||||
self._functions = {}
|
||||
|
||||
def interpret_statement(self, stmt, local_vars, allow_recursion=20):
|
||||
if allow_recursion < 0:
|
||||
raise ExtractorError('Recursion limit reached')
|
||||
|
||||
if stmt.startswith('var '):
|
||||
stmt = stmt[len('var '):]
|
||||
ass_m = re.match(r'^(?P<out>[a-z]+)(?:\[(?P<index>[^\]]+)\])?' +
|
||||
r'=(?P<expr>.*)$', stmt)
|
||||
if ass_m:
|
||||
if ass_m.groupdict().get('index'):
|
||||
def assign(val):
|
||||
lvar = local_vars[ass_m.group('out')]
|
||||
idx = self.interpret_expression(
|
||||
ass_m.group('index'), local_vars, allow_recursion)
|
||||
assert isinstance(idx, int)
|
||||
lvar[idx] = val
|
||||
return val
|
||||
expr = ass_m.group('expr')
|
||||
else:
|
||||
def assign(val):
|
||||
local_vars[ass_m.group('out')] = val
|
||||
return val
|
||||
expr = ass_m.group('expr')
|
||||
elif stmt.startswith('return '):
|
||||
assign = lambda v: v
|
||||
expr = stmt[len('return '):]
|
||||
else:
|
||||
raise ExtractorError(
|
||||
'Cannot determine left side of statement in %r' % stmt)
|
||||
|
||||
v = self.interpret_expression(expr, local_vars, allow_recursion)
|
||||
return assign(v)
|
||||
|
||||
def interpret_expression(self, expr, local_vars, allow_recursion):
|
||||
if expr.isdigit():
|
||||
return int(expr)
|
||||
|
||||
if expr.isalpha():
|
||||
return local_vars[expr]
|
||||
|
||||
m = re.match(r'^(?P<in>[a-z]+)\.(?P<member>.*)$', expr)
|
||||
if m:
|
||||
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:]
|
||||
|
||||
m = re.match(
|
||||
r'^(?P<in>[a-z]+)\[(?P<idx>.+)\]$', expr)
|
||||
if m:
|
||||
val = local_vars[m.group('in')]
|
||||
idx = self.interpret_expression(
|
||||
m.group('idx'), local_vars, allow_recursion - 1)
|
||||
return val[idx]
|
||||
|
||||
m = re.match(r'^(?P<a>.+?)(?P<op>[%])(?P<b>.+?)$', expr)
|
||||
if m:
|
||||
a = self.interpret_expression(
|
||||
m.group('a'), local_vars, allow_recursion)
|
||||
b = self.interpret_expression(
|
||||
m.group('b'), local_vars, allow_recursion)
|
||||
return a % b
|
||||
|
||||
m = re.match(
|
||||
r'^(?P<func>[a-zA-Z$]+)\((?P<args>[a-z0-9,]+)\)$', expr)
|
||||
if m:
|
||||
fname = m.group('func')
|
||||
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_function(self, funcname):
|
||||
func_m = re.search(
|
||||
r'function ' + re.escape(funcname) +
|
||||
r'\((?P<args>[a-z,]+)\){(?P<code>[^}]+)}',
|
||||
self.code)
|
||||
argnames = func_m.group('args').split(',')
|
||||
|
||||
def resf(args):
|
||||
local_vars = dict(zip(argnames, args))
|
||||
for stmt in func_m.group('code').split(';'):
|
||||
res = self.interpret_statement(stmt, local_vars)
|
||||
return res
|
||||
return resf
|
||||
|
||||
Loading…
Reference in a new issue