97b1df1629
Avoid to create a SSLContext in AsyncHTTPTransportNoHttp
See:
* 0f61aa58d6/httpx/_transports/default.py (L271)
* https://github.com/encode/httpx/issues/2298
238 lines
7.1 KiB
Python
238 lines
7.1 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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# lint: pylint
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# pylint: disable=missing-module-docstring, global-statement
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import asyncio
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import logging
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import random
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from ssl import SSLContext
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import threading
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from typing import Any, Dict
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import httpx
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from httpx_socks import AsyncProxyTransport
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from python_socks import parse_proxy_url, ProxyConnectionError, ProxyTimeoutError, ProxyError
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from searx import logger
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# Optional uvloop (support Python 3.6)
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try:
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import uvloop
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except ImportError:
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pass
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else:
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uvloop.install()
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logger = logger.getChild('searx.network.client')
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LOOP = None
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SSLCONTEXTS: Dict[Any, SSLContext] = {}
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def shuffle_ciphers(ssl_context):
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"""Shuffle httpx's default ciphers of a SSL context randomly.
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From `What Is TLS Fingerprint and How to Bypass It`_
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> When implementing TLS fingerprinting, servers can't operate based on a
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> locked-in whitelist database of fingerprints. New fingerprints appear
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> when web clients or TLS libraries release new versions. So, they have to
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> live off a blocklist database instead.
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> ...
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> It's safe to leave the first three as is but shuffle the remaining ciphers
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> and you can bypass the TLS fingerprint check.
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.. _What Is TLS Fingerprint and How to Bypass It:
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https://www.zenrows.com/blog/what-is-tls-fingerprint#how-to-bypass-tls-fingerprinting
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"""
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c_list = httpx._config.DEFAULT_CIPHERS.split(':') # pylint: disable=protected-access
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sc_list, c_list = c_list[:3], c_list[3:]
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random.shuffle(c_list)
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ssl_context.set_ciphers(":".join(sc_list + c_list))
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def get_sslcontexts(proxy_url=None, cert=None, verify=True, trust_env=True, http2=False):
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key = (proxy_url, cert, verify, trust_env, http2)
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if key not in SSLCONTEXTS:
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SSLCONTEXTS[key] = httpx.create_ssl_context(cert, verify, trust_env, http2)
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shuffle_ciphers(SSLCONTEXTS[key])
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return SSLCONTEXTS[key]
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class AsyncHTTPTransportNoHttp(httpx.AsyncHTTPTransport):
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"""Block HTTP request
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The constructor is blank because httpx.AsyncHTTPTransport.__init__ creates an SSLContext unconditionally:
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https://github.com/encode/httpx/blob/0f61aa58d66680c239ce43c8cdd453e7dc532bfc/httpx/_transports/default.py#L271
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Each SSLContext consumes more than 500kb of memory, since there is about one network per engine.
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In consequence, this class overrides all public methods
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For reference: https://github.com/encode/httpx/issues/2298
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"""
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def __init__(self, *args, **kwargs):
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# pylint: disable=super-init-not-called
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# this on purpose if the base class is not called
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pass
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async def handle_async_request(self, request):
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raise httpx.UnsupportedProtocol('HTTP protocol is disabled')
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async def aclose(self) -> None:
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pass
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async def __aenter__(self):
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return self
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async def __aexit__(
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self,
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exc_type=None,
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exc_value=None,
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traceback=None,
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) -> None:
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pass
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class AsyncProxyTransportFixed(AsyncProxyTransport):
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"""Fix httpx_socks.AsyncProxyTransport
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Map python_socks exceptions to httpx.ProxyError exceptions
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"""
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async def handle_async_request(self, request):
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try:
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return await super().handle_async_request(request)
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except ProxyConnectionError as e:
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raise httpx.ProxyError("ProxyConnectionError: " + e.strerror, request=request) from e
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except ProxyTimeoutError as e:
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raise httpx.ProxyError("ProxyTimeoutError: " + e.args[0], request=request) from e
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except ProxyError as e:
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raise httpx.ProxyError("ProxyError: " + e.args[0], request=request) from e
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def get_transport_for_socks_proxy(verify, http2, local_address, proxy_url, limit, retries):
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# support socks5h (requests compatibility):
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# https://requests.readthedocs.io/en/master/user/advanced/#socks
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# socks5:// hostname is resolved on client side
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# socks5h:// hostname is resolved on proxy side
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rdns = False
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socks5h = 'socks5h://'
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if proxy_url.startswith(socks5h):
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proxy_url = 'socks5://' + proxy_url[len(socks5h) :]
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rdns = True
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proxy_type, proxy_host, proxy_port, proxy_username, proxy_password = parse_proxy_url(proxy_url)
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verify = get_sslcontexts(proxy_url, None, verify, True, http2) if verify is True else verify
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return AsyncProxyTransportFixed(
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proxy_type=proxy_type,
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proxy_host=proxy_host,
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proxy_port=proxy_port,
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username=proxy_username,
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password=proxy_password,
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rdns=rdns,
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loop=get_loop(),
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verify=verify,
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http2=http2,
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local_address=local_address,
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limits=limit,
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retries=retries,
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)
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def get_transport(verify, http2, local_address, proxy_url, limit, retries):
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verify = get_sslcontexts(None, None, verify, True, http2) if verify is True else verify
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return httpx.AsyncHTTPTransport(
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# pylint: disable=protected-access
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verify=verify,
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http2=http2,
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limits=limit,
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proxy=httpx._config.Proxy(proxy_url) if proxy_url else None,
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local_address=local_address,
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retries=retries,
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)
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def new_client(
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# pylint: disable=too-many-arguments
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enable_http,
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verify,
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enable_http2,
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max_connections,
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max_keepalive_connections,
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keepalive_expiry,
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proxies,
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local_address,
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retries,
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max_redirects,
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hook_log_response,
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):
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limit = httpx.Limits(
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max_connections=max_connections,
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max_keepalive_connections=max_keepalive_connections,
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keepalive_expiry=keepalive_expiry,
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)
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# See https://www.python-httpx.org/advanced/#routing
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mounts = {}
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for pattern, proxy_url in proxies.items():
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if not enable_http and pattern.startswith('http://'):
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continue
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if proxy_url.startswith('socks4://') or proxy_url.startswith('socks5://') or proxy_url.startswith('socks5h://'):
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mounts[pattern] = get_transport_for_socks_proxy(
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verify, enable_http2, local_address, proxy_url, limit, retries
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)
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else:
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mounts[pattern] = get_transport(verify, enable_http2, local_address, proxy_url, limit, retries)
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if not enable_http:
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mounts['http://'] = AsyncHTTPTransportNoHttp()
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transport = get_transport(verify, enable_http2, local_address, None, limit, retries)
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event_hooks = None
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if hook_log_response:
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event_hooks = {'response': [hook_log_response]}
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return httpx.AsyncClient(
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transport=transport,
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mounts=mounts,
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max_redirects=max_redirects,
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event_hooks=event_hooks,
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)
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def get_loop():
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return LOOP
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def init():
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# log
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for logger_name in (
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'httpx',
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'httpcore.proxy',
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'httpcore.connection',
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'httpcore.http11',
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'httpcore.http2',
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'hpack.hpack',
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'hpack.table',
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):
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logging.getLogger(logger_name).setLevel(logging.WARNING)
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# loop
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def loop_thread():
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global LOOP
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LOOP = asyncio.new_event_loop()
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LOOP.run_forever()
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thread = threading.Thread(
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target=loop_thread,
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name='asyncio_loop',
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daemon=True,
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)
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thread.start()
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init()
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