From b2e4bf992ea1600973c06aaf7f9ce545f604d184 Mon Sep 17 00:00:00 2001
From: Vladimir Magamedov <vladimir@magamedov.com>
Date: Sat, 30 May 2020 03:14:26 +0300
Subject: [PATCH] Added server:Stream.user_agent property and corresponding
 property in the RecvRequest event

---
 grpclib/events.py           | 4 ++++
 grpclib/server.py           | 7 ++++++-
 tests/test_server_events.py | 1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/grpclib/events.py b/grpclib/events.py
index 367d378..1f70a4a 100644
--- a/grpclib/events.py
+++ b/grpclib/events.py
@@ -164,6 +164,7 @@ class RecvRequest(_Event, metaclass=_EventMeta):
     :param read-only method_name: RPC's method name
     :param read-only deadline: request's :py:class:`~grpclib.metadata.Deadline`
     :param read-only content_type: request's content type
+    :param read-only user_agent: request's user agent
     """
     __payload__ = ('metadata', 'method_func')
 
@@ -172,6 +173,7 @@ class RecvRequest(_Event, metaclass=_EventMeta):
     method_name: str
     deadline: Optional[Deadline]
     content_type: str
+    user_agent: Optional[str]
 
 
 class SendInitialMetadata(_Event, metaclass=_EventMeta):
@@ -205,6 +207,7 @@ class _DispatchServerEvents(_DispatchCommonEvents):
         method_name: str,
         deadline: Optional[Deadline],
         content_type: str,
+        user_agent: Optional[str],
     ) -> Tuple[_Metadata, 'IServerMethodFunc']:
         return await self.__dispatch__(RecvRequest(  # type: ignore
             metadata=metadata,
@@ -212,6 +215,7 @@ class _DispatchServerEvents(_DispatchCommonEvents):
             method_name=method_name,
             deadline=deadline,
             content_type=content_type,
+            user_agent=user_agent,
         ))
 
     @_dispatches(SendInitialMetadata)
diff --git a/grpclib/server.py b/grpclib/server.py
index 1f4c193..6df047e 100644
--- a/grpclib/server.py
+++ b/grpclib/server.py
@@ -83,6 +83,7 @@ class Stream(StreamIterator[_RecvType], Generic[_RecvType, _SendType]):
         status_details_codec: Optional[StatusDetailsCodecBase],
         dispatch: _DispatchServerEvents,
         deadline: Optional[Deadline] = None,
+        user_agent: Optional[str] = None,
     ):
         self._stream = stream
         self._method_name = method_name
@@ -97,6 +98,8 @@ class Stream(StreamIterator[_RecvType], Generic[_RecvType, _SendType]):
         #: Invocation metadata, received with headers from the client.
         #: Represented as a multi-dict object.
         self.metadata: Optional[_Metadata] = None
+        #: Client's user-agent
+        self.user_agent = user_agent
 
     @property
     def _content_type(self) -> str:
@@ -406,12 +409,13 @@ async def request_handler(
             return
 
         metadata = decode_metadata(headers)
+        user_agent = headers_map.get('user-agent')
 
         async with Stream(
             _stream, method_name, method.cardinality,
             method.request_type, method.reply_type,
             codec=codec, status_details_codec=status_details_codec,
-            dispatch=dispatch, deadline=deadline,
+            dispatch=dispatch, deadline=deadline, user_agent=user_agent,
         ) as stream:
             deadline_wrapper: 'ContextManager[Any]'
             if deadline is None:
@@ -428,6 +432,7 @@ async def request_handler(
                         method_name=method_name,
                         deadline=deadline,
                         content_type=content_type,
+                        user_agent=user_agent,
                     )
                     await method_func(stream)
             except GRPCError:
diff --git a/tests/test_server_events.py b/tests/test_server_events.py
index cd74d90..030e464 100644
--- a/tests/test_server_events.py
+++ b/tests/test_server_events.py
@@ -59,6 +59,7 @@ async def test_recv_request():
     assert event.method_name == '/dummy.DummyService/UnaryUnary'
     assert event.deadline.time_remaining() > 0
     assert event.content_type == 'application/grpc+proto'
+    assert event.user_agent.startswith('grpc-python-grpclib')
 
 
 @pytest.mark.asyncio