asyncio doc: add examples showing the 3 ways to wait for data from an open

socket

Doc/library/asyncio-eventloop.rst

@@ -339,6 +339,10 @@ On Windows with :class:`ProactorEventLoop`, these methods are not supported.
 
    Stop watching the file descriptor for write availability.
 
+The :ref:`watch a file descriptor for read events <asyncio-watch-read-event>`
+example uses the low-level :meth:`BaseEventLoop.add_reader` method to register
+the file descriptor of a socket.
+
 
 Low-level socket operations
 ---------------------------
@@ -663,10 +667,59 @@ Print ``"Hello World"`` every two seconds using a callback scheduled by the
    uses a :ref:`coroutine <coroutine>`.
 
 
-Example: Set signal handlers for SIGINT and SIGTERM
+.. _asyncio-watch-read-event:
----------------------------------------------------
 
-Register handlers for signals :py:data:`SIGINT` and :py:data:`SIGTERM`::
+Watch a file descriptor for read events
+---------------------------------------
+
+Wait until a file descriptor received some data using the
+:meth:`BaseEventLoop.add_reader` method and then close the event loop::
+
+    import asyncio
+    import socket
+
+    # Create a pair of connected file descriptors
+    rsock, wsock = socket.socketpair()
+    loop = asyncio.get_event_loop()
+
+    def reader():
+        data = rsock.recv(100)
+        print("Received:", data.decode())
+        # We are done: unregister the register
+        loop.remove_reader(rsock)
+        # Stop the event loop
+        loop.stop()
+
+    # Wait for read event
+    loop.add_reader(rsock, reader)
+
+    # Simulate the reception of data from the network
+    loop.call_soon(wsock.send, 'abc'.encode())
+
+    # Run the event loop
+    loop.run_forever()
+
+    # We are done, close sockets and the event loop
+    rsock.close()
+    wsock.close()
+    loop.close()
+
+.. seealso::
+
+   The :ref:`register an open socket to wait for data using a protocol
+   <asyncio-register-socket>` example uses a low-level protocol created by the
+   :meth:`BaseEventLoop.create_connection` method.
+
+   The :ref:`register an open socket to wait for data using streams
+   <asyncio-register-socket-streams>` example uses high-level streams
+   created by the :func:`open_connection` function in a coroutine.
+
+
+Set signal handlers for SIGINT and SIGTERM
+------------------------------------------
+
+Register handlers for signals :py:data:`SIGINT` and :py:data:`SIGTERM` using
+the :meth:`BaseEventLoop.add_signal_handler` method::
 
     import asyncio
     import functools
@@ -688,4 +741,3 @@ Register handlers for signals :py:data:`SIGINT` and :py:data:`SIGTERM`::
         loop.run_forever()
     finally:
         loop.close()
-

Doc/library/asyncio-protocol.rst

@@ -436,11 +436,11 @@ coroutine with ``yield from``. For example, the :meth:`StreamWriter.drain`
 coroutine can be used to wait until the write buffer is flushed.
 
 
-Protocol example: TCP echo server and client
+Protocol examples
-============================================
+=================
 
-Echo client
+TCP echo client
------------
+---------------
 
 TCP echo client example, send data and wait until the connection is closed::
 
@@ -473,8 +473,8 @@ having to write a short coroutine to handle the exception and stop the
 running loop. At :meth:`~BaseEventLoop.run_until_complete` exit, the loop is
 no longer running, so there is no need to stop the loop in case of an error.
 
-Echo server
+TCP echo server
------------
+---------------
 
 TCP echo server example, send back received data and close the connection::
 
@@ -511,4 +511,60 @@ TCP echo server example, send back received data and close the connection::
 methods are asynchronous. ``yield from`` is not needed because these transport
 methods are not coroutines.
 
+.. _asyncio-register-socket:
 
+Register an open socket to wait for data using a protocol
+---------------------------------------------------------
+
+Wait until a socket receives data using the
+:meth:`BaseEventLoop.create_connection` method with a protocol, and then close
+the event loop ::
+
+    import asyncio
+    import socket
+
+    # Create a pair of connected sockets
+    rsock, wsock = socket.socketpair()
+    loop = asyncio.get_event_loop()
+
+    class MyProtocol(asyncio.Protocol):
+        transport = None
+
+        def connection_made(self, transport):
+            self.transport = transport
+
+        def data_received(self, data):
+            print("Received:", data.decode())
+
+            # We are done: close the transport (it will call connection_lost())
+            self.transport.close()
+
+        def connection_lost(self, exc):
+            # The socket has been closed, stop the event loop
+            loop.stop()
+
+    # Register the socket to wait for data
+    connect_coro = loop.create_connection(MyProtocol, sock=rsock)
+    transport, protocol = loop.run_until_complete(connect_coro)
+
+    # Simulate the reception of data from the network
+    loop.call_soon(wsock.send, 'abc'.encode())
+
+    # Run the event loop
+    loop.run_forever()
+
+    # We are done, close sockets and the event loop
+    rsock.close()
+    wsock.close()
+    loop.close()
+
+.. seealso::
+
+   The :ref:`watch a file descriptor for read events
+   <asyncio-watch-read-event>` example uses the low-level
+   :meth:`BaseEventLoop.add_reader` method to register the file descriptor of a
+   socket.
+
+   The :ref:`register an open socket to wait for data using streams
+   <asyncio-register-socket-streams>` example uses high-level streams
+   created by the :func:`open_connection` function in a coroutine.

Doc/library/asyncio-stream.rst

@@ -283,3 +283,53 @@ Usage::
 
     python example.py http://example.com/path/page.html
 
+or with HTTPS::
+
+    python example.py https://example.com/path/page.html
+
+.. _asyncio-register-socket-streams:
+
+Register an open socket to wait for data using streams
+------------------------------------------------------
+
+Coroutine waiting until a socket receives data using the
+:func:`open_connection` function::
+
+    import asyncio
+    import socket
+
+    def wait_for_data(loop):
+        # Create a pair of connected sockets
+        rsock, wsock = socket.socketpair()
+
+        # Register the open socket to wait for data
+        reader, writer = yield from asyncio.open_connection(sock=rsock, loop=loop)
+
+        # Simulate the reception of data from the network
+        loop.call_soon(wsock.send, 'abc'.encode())
+
+        # Wait for data
+        data = yield from reader.read(100)
+
+        # Got data, we are done: close the socket
+        print("Received:", data.decode())
+        writer.close()
+
+        # Close the second socket
+        wsock.close()
+
+    loop = asyncio.get_event_loop()
+    loop.run_until_complete(wait_for_data(loop))
+    loop.close()
+
+.. seealso::
+
+   The :ref:`register an open socket to wait for data using a protocol
+   <asyncio-register-socket>` example uses a low-level protocol created by the
+   :meth:`BaseEventLoop.create_connection` method.
+
+   The :ref:`watch a file descriptor for read events
+   <asyncio-watch-read-event>` example uses the low-level
+   :meth:`BaseEventLoop.add_reader` method to register the file descriptor of a
+   socket.
+