Source code for pypac.os_settings

"""
Tools for getting the configured PAC file URL out of the OS settings.
"""

import platform
from sys import version_info

if version_info[0] == 2:
    from urllib import unquote  # type: ignore

    from urlparse import urlparse  # type: ignore
else:
    from urllib.parse import urlparse, unquote  # noqa


#: True if running on Windows.
ON_WINDOWS = platform.system() == "Windows"

#: True if running on macOS/OSX.
ON_DARWIN = platform.system() == "Darwin"

if ON_WINDOWS:
    try:
        import winreg
    except ImportError:  # PY2.
        import _winreg as winreg  # type: ignore

if ON_DARWIN:
    import SystemConfiguration  # type: ignore


_POLICIES_INTERNET_SETTINGS_PATH = "Software\\Policies\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"
_NORMAL_INTERNET_SETTINGS_PATH = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"


def _is_per_user_proxy_setting():
    """
    Get the PAC ``ProxySettingsPerUser`` value from the Windows Registry.

    See https://learn.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/microsoft-windows-ie-clientnetworkprotocolimplementation-hklmproxyenable.

    :return: True if settings are per-user (default), False if per-machine.
    :rtype: bool
    """
    try:
        with winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, _POLICIES_INTERNET_SETTINGS_PATH) as key:
            value, _ = winreg.QueryValueEx(key, "ProxySettingsPerUser")
            return value != 0
    except WindowsError:
        return True




def autoconfig_url_from_registry():
    """
    Get the PAC ``AutoConfigURL`` value from the Windows Registry.
    This setting is visible as the "use automatic configuration script" field in
    Internet Options > Connection > LAN Settings.

    The search order is:

    1. HKCU Policies (per-user Group Policy)
    2. HKLM Policies (machine Group Policy)
    3. HKCU Normal (user preference)
    4. HKLM Normal (machine default)

    If ``ProxySettingsPerUser`` is 0 (per-machine mode), HKCU entries are skipped.

    :return: The value from the registry, or None if the value isn't configured or available.
        Note that it may be a local filesystem path instead of a URL.
    :rtype: str|None
    :raises NotWindowsError: If called on a non-Windows platform.
    """
    if not ON_WINDOWS:
        raise NotWindowsError()

    per_user = _is_per_user_proxy_setting()

    for hive, path in [
        (winreg.HKEY_CURRENT_USER, _POLICIES_INTERNET_SETTINGS_PATH),
        (winreg.HKEY_LOCAL_MACHINE, _POLICIES_INTERNET_SETTINGS_PATH),
        (winreg.HKEY_CURRENT_USER, _NORMAL_INTERNET_SETTINGS_PATH),
        (winreg.HKEY_LOCAL_MACHINE, _NORMAL_INTERNET_SETTINGS_PATH),
    ]:
        if not per_user and hive == winreg.HKEY_CURRENT_USER:
            continue
        try:
            with winreg.OpenKey(hive, path) as key:
                value = winreg.QueryValueEx(key, "AutoConfigURL")[0]
            if not value:
                continue
            return value
        except WindowsError:
            pass

    return None





def autoconfig_url_from_preferences():
    """
    Get the PAC ``AutoConfigURL`` value from the macOS System Preferences.
    This setting is visible as the "URL" field in
    System Preferences > Network > Advanced... > Proxies > Automatic Proxy Configuration.

    :return: The value from the registry, or None if the value isn't configured or available.
        Note that it may be local filesystem path instead of a URL.
    :rtype: str|None
    :raises NotDarwinError: If called on a non-macOS/OSX platform.
    """
    if not ON_DARWIN:
        raise NotDarwinError()

    try:
        config = SystemConfiguration.SCDynamicStoreCopyProxies(None)
    except AttributeError:
        return  # Key or value not found.

    if all(
        (
            "ProxyAutoConfigEnable" in config,
            "ProxyAutoConfigURLString" in config,
            not config.get("ProxyAutoDiscoveryEnable", 0),
        )
    ):
        # Only return a value if it is enabled, not empty, and auto discovery is disabled.
        return str(config["ProxyAutoConfigURLString"])





def file_url_to_local_path(file_url):
    """
    Parse a ``AutoConfigURL`` value with ``file://`` scheme into a usable local filesystem path.

    :param file_url: Must start with ``file://``.
    :return: A local filesystem path. It might not exist.
    """
    parts = urlparse(file_url)
    path = unquote(parts.path)
    if path.startswith("/") and not path.startswith("//"):
        if ON_DARWIN:
            return path
        if len(parts.netloc) == 2 and parts.netloc[1] == ":":  # Drive letter and colon.
            return parts.netloc + path
        return "C:" + path  # Assume C drive if it's just a path starting with /.
    if len(path) > 2 and path[1] == ":":
        return path





class NotWindowsError(Exception):
    def __init__(self):
        super(NotWindowsError, self).__init__("Platform is not Windows.")





class NotDarwinError(Exception):
    def __init__(self):
        super(NotDarwinError, self).__init__("Platform is not macOS/OSX.")