# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
# pylint: disable=missing-module-docstring, global-statement
import asyncio
import logging
import random
from ssl import SSLContext
import threading
from typing import Any, Dict
import httpx
from httpx_socks import AsyncProxyTransport
from python_socks import parse_proxy_url, ProxyConnectionError, ProxyTimeoutError, ProxyError
from searx import logger
# Optional uvloop (support Python 3.6)
try:
import uvloop
except ImportError:
pass
else:
uvloop.install()
logger = logger.getChild('searx.network.client')
LOOP = None
SSLCONTEXTS: Dict[Any, SSLContext] = {}
def shuffle_ciphers(ssl_context):
"""Shuffle httpx's default ciphers of a SSL context randomly.
From `What Is TLS Fingerprint and How to Bypass It`_
> When implementing TLS fingerprinting, servers can't operate based on a
> locked-in whitelist database of fingerprints. New fingerprints appear
> when web clients or TLS libraries release new versions. So, they have to
> live off a blocklist database instead.
> ...
> It's safe to leave the first three as is but shuffle the remaining ciphers
> and you can bypass the TLS fingerprint check.
.. _What Is TLS Fingerprint and How to Bypass It:
https://www.zenrows.com/blog/what-is-tls-fingerprint#how-to-bypass-tls-fingerprinting
"""
c_list = httpx._config.DEFAULT_CIPHERS.split(':') # pylint: disable=protected-access
sc_list, c_list = c_list[:3], c_list[3:]
random.shuffle(c_list)
ssl_context.set_ciphers(":".join(sc_list + c_list))
def get_sslcontexts(proxy_url=None, cert=None, verify=True, trust_env=True, http2=False):
key = (proxy_url, cert, verify, trust_env, http2)
if key not in SSLCONTEXTS:
SSLCONTEXTS[key] = httpx.create_ssl_context(cert, verify, trust_env, http2)
shuffle_ciphers(SSLCONTEXTS[key])
return SSLCONTEXTS[key]
class AsyncHTTPTransportNoHttp(httpx.AsyncHTTPTransport):
"""Block HTTP request
The constructor is blank because httpx.AsyncHTTPTransport.__init__ creates an SSLContext unconditionally:
https://github.com/encode/httpx/blob/0f61aa58d66680c239ce43c8cdd453e7dc532bfc/httpx/_transports/default.py#L271
Each SSLContext consumes more than 500kb of memory, since there is about one network per engine.
In consequence, this class overrides all public methods
For reference: https://github.com/encode/httpx/issues/2298
"""
def __init__(self, *args, **kwargs):
# pylint: disable=super-init-not-called
# this on purpose if the base class is not called
pass
async def handle_async_request(self, request):
raise httpx.UnsupportedProtocol('HTTP protocol is disabled')
async def aclose(self) -> None:
pass
async def __aenter__(self):
return self
async def __aexit__(
self,
exc_type=None,
exc_value=None,
traceback=None,
) -> None:
pass
class AsyncProxyTransportFixed(AsyncProxyTransport):
"""Fix httpx_socks.AsyncProxyTransport
Map python_socks exceptions to httpx.ProxyError exceptions
"""
async def handle_async_request(self, request):
try:
return await super().handle_async_request(request)
except ProxyConnectionError as e:
raise httpx.ProxyError("ProxyConnectionError: " + e.strerror, request=request) from e
except ProxyTimeoutError as e:
raise httpx.ProxyError("ProxyTimeoutError: " + e.args[0], request=request) from e
except ProxyError as e:
raise httpx.ProxyError("ProxyError: " + e.args[0], request=request) from e
def get_transport_for_socks_proxy(verify, http2, local_address, proxy_url, limit, retries):
# support socks5h (requests compatibility):
# https://requests.readthedocs.io/en/master/user/advanced/#socks
# socks5:// hostname is resolved on client side
# socks5h:// hostname is resolved on proxy side
rdns = False
socks5h = 'socks5h://'
if proxy_url.startswith(socks5h):
proxy_url = 'socks5://' + proxy_url[len(socks5h) :]
rdns = True
proxy_type, proxy_host, proxy_port, proxy_username, proxy_password = parse_proxy_url(proxy_url)
verify = get_sslcontexts(proxy_url, None, verify, True, http2) if verify is True else verify
return AsyncProxyTransportFixed(
proxy_type=proxy_type,
proxy_host=proxy_host,
proxy_port=proxy_port,
username=proxy_username,
password=proxy_password,
rdns=rdns,
loop=get_loop(),
verify=verify,
http2=http2,
local_address=local_address,
limits=limit,
retries=retries,
)
def get_transport(verify, http2, local_address, proxy_url, limit, retries):
verify = get_sslcontexts(None, None, verify, True, http2) if verify is True else verify
return httpx.AsyncHTTPTransport(
# pylint: disable=protected-access
verify=verify,
http2=http2,
limits=limit,
proxy=httpx._config.Proxy(proxy_url) if proxy_url else None,
local_address=local_address,
retries=retries,
)
def new_client(
# pylint: disable=too-many-arguments
enable_http,
verify,
enable_http2,
max_connections,
max_keepalive_connections,
keepalive_expiry,
proxies,
local_address,
retries,
max_redirects,
hook_log_response,
):
limit = httpx.Limits(
max_connections=max_connections,
max_keepalive_connections=max_keepalive_connections,
keepalive_expiry=keepalive_expiry,
)
# See https://www.python-httpx.org/advanced/#routing
mounts = {}
for pattern, proxy_url in proxies.items():
if not enable_http and pattern.startswith('http://'):
continue
if proxy_url.startswith('socks4://') or proxy_url.startswith('socks5://') or proxy_url.startswith('socks5h://'):
mounts[pattern] = get_transport_for_socks_proxy(
verify, enable_http2, local_address, proxy_url, limit, retries
)
else:
mounts[pattern] = get_transport(verify, enable_http2, local_address, proxy_url, limit, retries)
if not enable_http:
mounts['http://'] = AsyncHTTPTransportNoHttp()
transport = get_transport(verify, enable_http2, local_address, None, limit, retries)
event_hooks = None
if hook_log_response:
event_hooks = {'response': [hook_log_response]}
return httpx.AsyncClient(
transport=transport,
mounts=mounts,
max_redirects=max_redirects,
event_hooks=event_hooks,
)
def get_loop():
return LOOP
def init():
# log
for logger_name in (
'httpx',
'httpcore.proxy',
'httpcore.connection',
'httpcore.http11',
'httpcore.http2',
'hpack.hpack',
'hpack.table',
):
logging.getLogger(logger_name).setLevel(logging.WARNING)
# loop
def loop_thread():
global LOOP
LOOP = asyncio.new_event_loop()
LOOP.run_forever()
thread = threading.Thread(
target=loop_thread,
name='asyncio_loop',
daemon=True,
)
thread.start()
init()
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