services/alinls/websocket/_http.py

"""
_http.py
websocket - WebSocket client library for Python

Copyright 2021 engn33r

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
import errno
import os
import socket
import sys

from ._exceptions import *
from ._logging import *
from ._socket import*
from ._ssl_compat import *
from ._url import *

from base64 import encodebytes as base64encode

__all__ = ["proxy_info", "connect", "read_headers"]

try:
    from python_socks.sync import Proxy
    from python_socks._errors import *
    from python_socks._types import ProxyType
    HAVE_PYTHON_SOCKS = True
except:
    HAVE_PYTHON_SOCKS = False

    class ProxyError(Exception):
        pass

    class ProxyTimeoutError(Exception):
        pass

    class ProxyConnectionError(Exception):
        pass


class proxy_info:

    def __init__(self, **options):
        self.proxy_host = options.get("http_proxy_host", None)
        if self.proxy_host:
            self.proxy_port = options.get("http_proxy_port", 0)
            self.auth = options.get("http_proxy_auth", None)
            self.no_proxy = options.get("http_no_proxy", None)
            self.proxy_protocol = options.get("proxy_type", "http")
            # Note: If timeout not specified, default python-socks timeout is 60 seconds
            self.proxy_timeout = options.get("timeout", None)
            if self.proxy_protocol not in ['http', 'socks4', 'socks4a', 'socks5', 'socks5h']:
                raise ProxyError("Only http, socks4, socks5 proxy protocols are supported")
        else:
            self.proxy_port = 0
            self.auth = None
            self.no_proxy = None
            self.proxy_protocol = "http"


def _start_proxied_socket(url, options, proxy):
    if not HAVE_PYTHON_SOCKS:
        raise WebSocketException("Python Socks is needed for SOCKS proxying but is not available")

    hostname, port, resource, is_secure = parse_url(url)

    if proxy.proxy_protocol == "socks5":
        rdns = False
        proxy_type = ProxyType.SOCKS5
    if proxy.proxy_protocol == "socks4":
        rdns = False
        proxy_type = ProxyType.SOCKS4
    # socks5h and socks4a send DNS through proxy
    if proxy.proxy_protocol == "socks5h":
        rdns = True
        proxy_type = ProxyType.SOCKS5
    if proxy.proxy_protocol == "socks4a":
        rdns = True
        proxy_type = ProxyType.SOCKS4

    ws_proxy = Proxy.create(
        proxy_type=proxy_type,
        host=proxy.proxy_host,
        port=int(proxy.proxy_port),
        username=proxy.auth[0] if proxy.auth else None,
        password=proxy.auth[1] if proxy.auth else None,
        rdns=rdns)

    sock = ws_proxy.connect(hostname, port, timeout=proxy.proxy_timeout)

    if is_secure and HAVE_SSL:
        sock = _ssl_socket(sock, options.sslopt, hostname)
    elif is_secure:
        raise WebSocketException("SSL not available.")

    return sock, (hostname, port, resource)


def connect(url, options, proxy, socket):
    # Use _start_proxied_socket() only for socks4 or socks5 proxy
    # Use _tunnel() for http proxy
    # TODO: Use python-socks for http protocol also, to standardize flow
    if proxy.proxy_host and not socket and not (proxy.proxy_protocol == "http"):
        return _start_proxied_socket(url, options, proxy)

    hostname, port, resource, is_secure = parse_url(url)

    if socket:
        return socket, (hostname, port, resource)

    addrinfo_list, need_tunnel, auth = _get_addrinfo_list(
        hostname, port, is_secure, proxy)
    if not addrinfo_list:
        raise WebSocketException(
            "Host not found.: " + hostname + ":" + str(port))

    sock = None
    try:
        sock = _open_socket(addrinfo_list, options.sockopt, options.timeout)
        if need_tunnel:
            sock = _tunnel(sock, hostname, port, auth)

        if is_secure:
            if HAVE_SSL:
                sock = _ssl_socket(sock, options.sslopt, hostname)
            else:
                raise WebSocketException("SSL not available.")

        return sock, (hostname, port, resource)
    except:
        if sock:
            sock.close()
        raise


def _get_addrinfo_list(hostname, port, is_secure, proxy):
    phost, pport, pauth = get_proxy_info(
        hostname, is_secure, proxy.proxy_host, proxy.proxy_port, proxy.auth, proxy.no_proxy)
    try:
        # when running on windows 10, getaddrinfo without socktype returns a socktype 0.
        # This generates an error exception: `_on_error: exception Socket type must be stream or datagram, not 0`
        # or `OSError: [Errno 22] Invalid argument` when creating socket. Force the socket type to SOCK_STREAM.
        if not phost:
            addrinfo_list = socket.getaddrinfo(
                hostname, port, 0, socket.SOCK_STREAM, socket.SOL_TCP)
            return addrinfo_list, False, None
        else:
            pport = pport and pport or 80
            # when running on windows 10, the getaddrinfo used above
            # returns a socktype 0. This generates an error exception:
            # _on_error: exception Socket type must be stream or datagram, not 0
            # Force the socket type to SOCK_STREAM
            addrinfo_list = socket.getaddrinfo(phost, pport, 0, socket.SOCK_STREAM, socket.SOL_TCP)
            return addrinfo_list, True, pauth
    except socket.gaierror as e:
        raise WebSocketAddressException(e)


def _open_socket(addrinfo_list, sockopt, timeout):
    err = None
    for addrinfo in addrinfo_list:
        family, socktype, proto = addrinfo[:3]
        sock = socket.socket(family, socktype, proto)
        sock.settimeout(timeout)
        for opts in DEFAULT_SOCKET_OPTION:
            sock.setsockopt(*opts)
        for opts in sockopt:
            sock.setsockopt(*opts)

        address = addrinfo[4]
        err = None
        while not err:
            try:
                sock.connect(address)
            except socket.error as error:
                error.remote_ip = str(address[0])
                try:
                    eConnRefused = (errno.ECONNREFUSED, errno.WSAECONNREFUSED)
                except:
                    eConnRefused = (errno.ECONNREFUSED, )
                if error.errno == errno.EINTR:
                    continue
                elif error.errno in eConnRefused:
                    err = error
                    continue
                else:
                    if sock:
                        sock.close()
                    raise error
            else:
                break
        else:
            continue
        break
    else:
        if err:
            raise err

    return sock


def _wrap_sni_socket(sock, sslopt, hostname, check_hostname):
    context = ssl.SSLContext(sslopt.get('ssl_version', ssl.PROTOCOL_TLS))

    if sslopt.get('cert_reqs', ssl.CERT_NONE) != ssl.CERT_NONE:
        cafile = sslopt.get('ca_certs', None)
        capath = sslopt.get('ca_cert_path', None)
        if cafile or capath:
            context.load_verify_locations(cafile=cafile, capath=capath)
        elif hasattr(context, 'load_default_certs'):
            context.load_default_certs(ssl.Purpose.SERVER_AUTH)
    if sslopt.get('certfile', None):
        context.load_cert_chain(
            sslopt['certfile'],
            sslopt.get('keyfile', None),
            sslopt.get('password', None),
        )
    # see
    # https://github.com/liris/websocket-client/commit/b96a2e8fa765753e82eea531adb19716b52ca3ca#commitcomment-10803153
    context.verify_mode = sslopt['cert_reqs']
    if HAVE_CONTEXT_CHECK_HOSTNAME:
        context.check_hostname = check_hostname
    if 'ciphers' in sslopt:
        context.set_ciphers(sslopt['ciphers'])
    if 'cert_chain' in sslopt:
        certfile, keyfile, password = sslopt['cert_chain']
        context.load_cert_chain(certfile, keyfile, password)
    if 'ecdh_curve' in sslopt:
        context.set_ecdh_curve(sslopt['ecdh_curve'])

    return context.wrap_socket(
        sock,
        do_handshake_on_connect=sslopt.get('do_handshake_on_connect', True),
        suppress_ragged_eofs=sslopt.get('suppress_ragged_eofs', True),
        server_hostname=hostname,
    )


def _ssl_socket(sock, user_sslopt, hostname):
    sslopt = dict(cert_reqs=ssl.CERT_REQUIRED)
    sslopt.update(user_sslopt)

    certPath = os.environ.get('WEBSOCKET_CLIENT_CA_BUNDLE')
    if certPath and os.path.isfile(certPath) \
            and user_sslopt.get('ca_certs', None) is None:
        sslopt['ca_certs'] = certPath
    elif certPath and os.path.isdir(certPath) \
            and user_sslopt.get('ca_cert_path', None) is None:
        sslopt['ca_cert_path'] = certPath

    if sslopt.get('server_hostname', None):
        hostname = sslopt['server_hostname']

    check_hostname = sslopt["cert_reqs"] != ssl.CERT_NONE and sslopt.pop(
        'check_hostname', True)
    sock = _wrap_sni_socket(sock, sslopt, hostname, check_hostname)

    if not HAVE_CONTEXT_CHECK_HOSTNAME and check_hostname:
        match_hostname(sock.getpeercert(), hostname)

    return sock


def _tunnel(sock, host, port, auth):
    debug("Connecting proxy...")
    connect_header = "CONNECT %s:%d HTTP/1.1\r\n" % (host, port)
    connect_header += "Host: %s:%d\r\n" % (host, port)

    # TODO: support digest auth.
    if auth and auth[0]:
        auth_str = auth[0]
        if auth[1]:
            auth_str += ":" + auth[1]
        encoded_str = base64encode(auth_str.encode()).strip().decode().replace('\n', '')
        connect_header += "Proxy-Authorization: Basic %s\r\n" % encoded_str
    connect_header += "\r\n"
    dump("request header", connect_header)

    send(sock, connect_header)

    try:
        status, resp_headers, status_message = read_headers(sock)
    except Exception as e:
        raise WebSocketProxyException(str(e))

    if status != 200:
        raise WebSocketProxyException(
            "failed CONNECT via proxy status: %r" % status)

    return sock


def read_headers(sock):
    status = None
    status_message = None
    headers = {}
    trace("--- response header ---")

    while True:
        line = recv_line(sock)
        line = line.decode('utf-8').strip()
        if not line:
            break
        trace(line)
        if not status:

            status_info = line.split(" ", 2)
            status = int(status_info[1])
            if len(status_info) > 2:
                status_message = status_info[2]
        else:
            kv = line.split(":", 1)
            if len(kv) == 2:
                key, value = kv
                if key.lower() == "set-cookie" and headers.get("set-cookie"):
                    headers["set-cookie"] = headers.get("set-cookie") + "; " + value.strip()
                else:
                    headers[key.lower()] = value.strip()
            else:
                raise WebSocketException("Invalid header")

    trace("-----------------------")

    return status, headers, status_message