mirror of
https://github.com/mikf/gallery-dl.git
synced 2024-11-23 11:12:40 +01:00
129 lines
3.9 KiB
Python
129 lines
3.9 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# Copyright 2015-2019 Mike Fährmann
|
|
#
|
|
# This program is free software; you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License version 2 as
|
|
# published by the Free Software Foundation.
|
|
|
|
"""Methods to access sites behind Cloudflare protection"""
|
|
|
|
import re
|
|
import time
|
|
import operator
|
|
import urllib.parse
|
|
from . import text
|
|
|
|
|
|
def is_challenge(response):
|
|
return (response.status_code == 503 and
|
|
response.headers.get("Server", "").startswith("cloudflare") and
|
|
b"jschl-answer" in response.content)
|
|
|
|
|
|
def solve_challenge(session, response, kwargs):
|
|
"""Solve Cloudflare challenge and get cfclearance cookie"""
|
|
parsed = urllib.parse.urlsplit(response.url)
|
|
root = parsed.scheme + "://" + parsed.netloc
|
|
|
|
cf_kwargs = kwargs.copy()
|
|
headers = cf_kwargs["headers"] = (
|
|
kwargs["headers"].copy() if "headers" in kwargs else {})
|
|
params = cf_kwargs["params"] = (
|
|
kwargs["params"].copy() if "params" in kwargs else {})
|
|
|
|
page = response.text
|
|
params["pass"] = text.extract(page, 'name="pass" value="', '"')[0]
|
|
params["jschl_vc"] = text.extract(page, 'name="jschl_vc" value="', '"')[0]
|
|
params["jschl_answer"] = solve_js_challenge(page, parsed.netloc)
|
|
headers["Referer"] = response.url
|
|
|
|
time.sleep(4)
|
|
|
|
url = root + "/cdn-cgi/l/chk_jschl"
|
|
cf_kwargs["allow_redirects"] = False
|
|
cf_response = session.request(response.request.method, url, **cf_kwargs)
|
|
|
|
location = cf_response.headers["Location"]
|
|
if location[0] == "/":
|
|
location = root + location
|
|
return location
|
|
|
|
|
|
def solve_js_challenge(page, netloc):
|
|
"""Evaluate JS challenge in 'page' to get 'jschl_answer' value"""
|
|
|
|
# build variable name
|
|
# e.g. '...f, wqnVscP={"DERKbJk":+(...' --> wqnVscP.DERKbJk
|
|
data, pos = text.extract_all(page, (
|
|
('var' , ',f, ', '='),
|
|
('key' , '"' , '"'),
|
|
('expr', ':' , '}'),
|
|
))
|
|
variable = "{}.{}".format(data["var"], data["key"])
|
|
vlength = len(variable)
|
|
|
|
# evaluate the initial expression
|
|
solution = evaluate_expression(data["expr"])
|
|
|
|
# iterator over all remaining expressions
|
|
# and combine their values in 'solution'
|
|
expressions = text.extract(
|
|
page, "'challenge-form');", "f.submit();", pos)[0]
|
|
for expr in expressions.split(";")[1:]:
|
|
|
|
if expr.startswith(variable):
|
|
# select arithmetc function based on operator (+/-/*)
|
|
func = OPERATORS[expr[vlength]]
|
|
# evaluate the rest of the expression
|
|
value = evaluate_expression(expr[vlength+2:])
|
|
# combine expression value with our current solution
|
|
solution = func(solution, value)
|
|
|
|
elif expr.startswith("a.value"):
|
|
# add length of hostname
|
|
solution += len(netloc)
|
|
|
|
if ".toFixed(" in expr:
|
|
# trim solution to 10 decimal places
|
|
# and strip trailing zeros
|
|
solution = "{:.10f}".format(solution).rstrip("0")
|
|
|
|
return solution
|
|
|
|
|
|
def evaluate_expression(expr, split_re=re.compile(r"\(+([^)]*)\)")):
|
|
"""Evaluate a single Javascript expression for the challenge"""
|
|
|
|
if "/" in expr:
|
|
# split the expression in numerator and denominator subexpressions,
|
|
# evaluate them separately,
|
|
# and return their fraction-result
|
|
num, _, denom = expr.partition("/")
|
|
return evaluate_expression(num) / evaluate_expression(denom)
|
|
|
|
# iterate over all subexpressions,
|
|
# evaluate them,
|
|
# and accumulate their values in 'result'
|
|
result = ""
|
|
for subexpr in split_re.findall(expr):
|
|
result += str(sum(
|
|
VALUES[part]
|
|
for part in subexpr.split("[]")
|
|
))
|
|
return int(result)
|
|
|
|
|
|
OPERATORS = {
|
|
"+": operator.add,
|
|
"-": operator.sub,
|
|
"*": operator.mul,
|
|
}
|
|
|
|
VALUES = {
|
|
"": 0,
|
|
"+": 0,
|
|
"!+": 1,
|
|
"+!!": 1,
|
|
}
|