Make client info available

.gitignore

@@ -124,3 +124,6 @@ dmypy.json
 
 # vim
 *.swp
+
+# vscode
+.vscode/

dbus_next/message_bus.py

@@ -9,13 +9,57 @@
 from .proxy_object import BaseProxyObject
 from . import introspection as intr
 
+import contextvars
 import inspect
 import socket
 import logging
 import xml.etree.ElementTree as ET
 import traceback
 
-from typing import Type, Callable, Optional, Union
+from typing import Type, Callable, Optional, Union, Any
+
+
+class ReadOnlyContextProxy:
+    """
+    A convenience class for making a context variable accessible as though it
+    were a local.  Any request for an attribute (other than `set_value`) on the
+    proxy will be passed through to the underlying variable.  Attributes are
+    immutable.
+
+    :param name: The name of the context variable.
+    """
+    def __init__(self, name: str):
+        self._obj = contextvars.ContextVar(name)
+
+    def __getattr__(self, name: str) -> Any:
+        proxy = self._obj.get()
+        return getattr(proxy, name)
+
+    def set_value(self, value: Any):
+        """
+        Set the value of the underlying context variable.
+        """
+        self._obj.set(value)
+
+
+"""
+The :class:`Message <dbus.message.Message>` object currently being handled.
+
+Client code can use this to obtain access to details from the message without
+modifying their public API.  Typical use is:
+
+```
+from dbus_next.message_bus import current_message
+
+@method()
+def echo_sender() -> 's':
+    return current_message.sender
+```
+
+Attempts to access any attribute of `current_message` outside of a message context
+will result in a `LookupError` being raised.
+"""
+current_message = ReadOnlyContextProxy("current_message")
 
 
 class BaseMessageBus:
@@ -661,6 +705,7 @@ def send_error(self, exc):
         return SendReply()
 
     def _process_message(self, msg):
+        current_message.set_value(msg)
         handled = False
 
         for handler in self._user_message_handlers:

dbus_next/service.py

@@ -88,7 +88,7 @@ def echo_two(self, val1: 's', val2: 'u') -> 'su':
     def decorator(fn):
         @wraps(fn)
         def wrapped(*args, **kwargs):
-            fn(*args, **kwargs)
+            return fn(*args, **kwargs)
 
         fn_name = name if name else fn.__name__
         wrapped.__dict__['__DBUS_METHOD'] = _Method(fn, fn_name, disabled=disabled)

test/client/test_methods.py

@@ -2,6 +2,7 @@
 from dbus_next.service import ServiceInterface, method
 import dbus_next.introspection as intr
 from dbus_next import aio, glib, DBusError
+from dbus_next.message_bus import current_message
 from test.util import check_gi_repository, skip_reason_no_gi
 
 import pytest
@@ -37,6 +38,10 @@ def EchoThree(self, what1: 's', what2: 's', what3: 's') -> 'sss':
     def ThrowsError(self):
         raise DBusError('test.error', 'something went wrong')
 
+    @method()
+    def UsesCurrentMessage(self) -> 's':
+        return current_message.sender
+
 
 @pytest.mark.asyncio
 async def test_aio_proxy_object():
@@ -79,6 +84,9 @@ async def test_aio_proxy_object():
     result = await interface.call_echo_string('no reply', flags=MessageFlag.NO_REPLY_EXPECTED)
     assert result is None
 
+    result = await interface.call_uses_current_message()
+    assert result
+
     with pytest.raises(DBusError):
         try:
             await interface.call_throws_error()

test/client/test_signals.py

@@ -3,6 +3,7 @@
 from dbus_next import Message
 from dbus_next.introspection import Node
 from dbus_next.constants import RequestNameReply
+from dbus_next.message_bus import current_message
 
 import pytest
 
@@ -53,6 +54,7 @@ def single_handler(value):
             nonlocal single_counter
             nonlocal err
             assert value == 'hello'
+            assert current_message.sender
             single_counter += 1
         except Exception as e:
             err = e
@@ -65,6 +67,7 @@ def multiple_handler(value1, value2):
         try:
             assert value1 == 'hello'
             assert value2 == 'world'
+            assert current_message.sender
             multiple_counter += 1
         except Exception as e:
             err = e

test/test_tcp_address.py

@@ -15,8 +15,12 @@ async def test_tcp_connection_with_forwarding(event_loop):
 
     addr_info = parse_address(os.environ.get('DBUS_SESSION_BUS_ADDRESS'))
     assert addr_info
-    assert 'abstract' in addr_info[0][1]
-    path = f'\0{addr_info[0][1]["abstract"]}'
+    if 'abstract' in addr_info[0][1]:
+        path = f'\0{addr_info[0][1]["abstract"]}'
+    elif 'path' in addr_info[0][1]:
+        path = addr_info[0][1]['path']
+
+    assert path
 
     async def handle_connection(tcp_reader, tcp_writer):
         unix_reader, unix_writer = await asyncio.open_unix_connection(path)