app: Handle ConnectionResetError

Fix: #22

Author: zjkmxy

src/ndn/app.py

@@ -290,6 +290,8 @@ def run_forever(self, after_start: Awaitable = None) -> bool:
         A non-async wrapper of :meth:`main_loop`.
 
         :param after_start: the coroutine to start after connection to NFD is established.
+        :return: ``True`` if the connection is shutdown not by ``Ctrl+C``.
+            For example, manually or by the other side.
 
         :examples:
             .. code-block:: python3

src/ndn/transport/stream_socket.py

@@ -65,7 +65,7 @@ async def run(self):
                 bio.write(await self.reader.readexactly(siz))
                 buf = bio.getvalue()
                 aio.ensure_future(self.callback(typ, buf))
-            except aio.IncompleteReadError:
+            except (aio.IncompleteReadError, ConnectionResetError):
                 self.shutdown()
 
     def send(self, data: bytes):

src/ndn/types.py

@@ -43,6 +43,14 @@ class InterestTimeout(Exception):
 class InterestCanceled(Exception):
     """
     Raised when an Interest is cancelled due to the loss of connection to NFD.
+
+    .. note::
+        A very large packet may cause NFD shutting down the connection.
+        More specifically,
+
+        - The face is shutdown.
+        - All pending Interests are cancelled with this exception.
+        - ``App.run_forever()`` returns ``True``.
     """
     pass