path: root/libs/websocket/_http.py

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

Copyright 2023 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
from base64 import encodebytes as base64encode

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

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

try:
    from python_socks._errors import *
    from python_socks._types import ProxyType
    from python_socks.sync import Proxy

    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("http_proxy_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: str, options, proxy) -> tuple:
    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 == "socks4":
        rdns = False
        proxy_type = ProxyType.SOCKS4
    # socks4a sends DNS through proxy
    elif proxy.proxy_protocol == "socks4a":
        rdns = True
        proxy_type = ProxyType.SOCKS4
    elif proxy.proxy_protocol == "socks5":
        rdns = False
        proxy_type = ProxyType.SOCKS5
    # socks5h sends DNS through proxy
    elif proxy.proxy_protocol == "socks5h":
        rdns = True
        proxy_type = ProxyType.SOCKS5

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

    return sock, (hostname, port, resource)


def connect(url: str, 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 proxy.proxy_protocol != "http":
        return _start_proxied_socket(url, options, proxy)

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

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

    addrinfo_list, need_tunnel, auth = _get_addrinfo_list(
        hostname, port_from_url, is_secure, proxy
    )
    if not addrinfo_list:
        raise WebSocketException(f"Host not found.: {hostname}:{port_from_url}")

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

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

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


def _get_addrinfo_list(hostname, port: int, is_secure: bool, proxy) -> tuple:
    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:
                sock.close()
                error.remote_ip = str(address[0])
                try:
                    eConnRefused = (
                        errno.ECONNREFUSED,
                        errno.WSAECONNREFUSED,
                        errno.ENETUNREACH,
                    )
                except AttributeError:
                    eConnRefused = (errno.ECONNREFUSED, errno.ENETUNREACH)
                if error.errno not in eConnRefused:
                    raise error
                err = error
                continue
            else:
                break
        else:
            continue
        break
    else:
        if err:
            raise err

    return sock


def _wrap_sni_socket(sock: socket.socket, sslopt: dict, hostname, check_hostname):
    context = sslopt.get("context", None)
    if not context:
        context = ssl.SSLContext(sslopt.get("ssl_version", ssl.PROTOCOL_TLS_CLIENT))
        # Non default context need to manually enable SSLKEYLOGFILE support by setting the keylog_filename attribute.
        # For more details see also:
        # * https://docs.python.org/3.8/library/ssl.html?highlight=sslkeylogfile#context-creation
        # * https://docs.python.org/3.8/library/ssl.html?highlight=sslkeylogfile#ssl.SSLContext.keylog_filename
        context.keylog_filename = os.environ.get("SSLKEYLOGFILE", None)

        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),
            )

        # Python 3.10 switch to PROTOCOL_TLS_CLIENT defaults to "cert_reqs = ssl.CERT_REQUIRED" and "check_hostname = True"
        # If both disabled, set check_hostname before verify_mode
        # see https://github.com/liris/websocket-client/commit/b96a2e8fa765753e82eea531adb19716b52ca3ca#commitcomment-10803153
        if sslopt.get("cert_reqs", ssl.CERT_NONE) == ssl.CERT_NONE and not sslopt.get(
            "check_hostname", False
        ):
            context.check_hostname = False
            context.verify_mode = ssl.CERT_NONE
        else:
            context.check_hostname = sslopt.get("check_hostname", True)
            context.verify_mode = sslopt.get("cert_reqs", ssl.CERT_REQUIRED)

        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: socket.socket, user_sslopt: dict, hostname):
    sslopt: dict = 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.get("check_hostname", True)
    sock = _wrap_sni_socket(sock, sslopt, hostname, check_hostname)

    return sock


def _tunnel(sock: socket.socket, host, port: int, auth) -> socket.socket:
    debug("Connecting proxy...")
    connect_header = f"CONNECT {host}:{port} HTTP/1.1\r\n"
    connect_header += f"Host: {host}:{port}\r\n"

    # TODO: support digest auth.
    if auth and auth[0]:
        auth_str = auth[0]
        if auth[1]:
            auth_str += f":{auth[1]}"
        encoded_str = base64encode(auth_str.encode()).strip().decode().replace("\n", "")
        connect_header += f"Proxy-Authorization: Basic {encoded_str}\r\n"
    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(f"failed CONNECT via proxy status: {status}")

    return sock


def read_headers(sock: socket.socket) -> tuple:
    status = None
    status_message = None
    headers: dict = {}
    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:
                raise WebSocketException("Invalid header")
            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()

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

    return status, headers, status_message