From 219ffcce0fa211650b20668febe4b55a259d2f6d Mon Sep 17 00:00:00 2001
From: Rik Veenboer <rik.veenboer@gmail.com>
Date: Tue, 2 Jun 2015 21:20:49 +0200
Subject: [PATCH] add example using select/asyncore from
 http://etutorials.org/Programming/Python+tutorial/Part+IV+Network+and+Web+Programming/Chapter+19.+Sockets+and+Server-Side+Network+Protocol+Modules/19.3+Event-Driven+Socket+Programs/

---
 TcpClient.py          | 13 ++++++++++
 asyncore/TcpServer.py | 24 ++++++++++++++++++
 select/TcpServer.py   | 58 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 95 insertions(+)
 create mode 100644 TcpClient.py
 create mode 100644 asyncore/TcpServer.py
 create mode 100644 select/TcpServer.py

diff --git a/TcpClient.py b/TcpClient.py
new file mode 100644
index 0000000..367a1fb
--- /dev/null
+++ b/TcpClient.py
@@ -0,0 +1,13 @@
+import socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+sock.connect(('localhost', 8881))
+print "Connected to server"
+data = """A few lines of data
+to test the operation
+of both server and client."""
+for line in data.splitlines(  ):
+    sock.sendall(line+'\n')
+    print "Sent:", line
+    response = sock.recv(8192)
+    print "Received:", response
+sock.close(  )
\ No newline at end of file
diff --git a/asyncore/TcpServer.py b/asyncore/TcpServer.py
new file mode 100644
index 0000000..1c1de9f
--- /dev/null
+++ b/asyncore/TcpServer.py
@@ -0,0 +1,24 @@
+import asyncore
+import socket
+
+class MainServerSocket(asyncore.dispatcher):
+    def __init__(self, port):
+        asyncore.dispatcher.__init__(self)
+        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.bind(('',port))
+        self.listen(5)
+    def handle_accept(self):
+        newSocket, address = self.accept(  )
+        print "Connected from", address
+        SecondaryServerSocket(newSocket)
+
+class SecondaryServerSocket(asyncore.dispatcher_with_send):
+    def handle_read(self):
+        receivedData = self.recv(8192)
+        if receivedData: self.send(receivedData)
+        else: self.close(  )
+    def handle_close(self):
+        print "Disconnected from", self.getpeername(  )
+
+MainServerSocket(8881)
+asyncore.loop(  )
\ No newline at end of file
diff --git a/select/TcpServer.py b/select/TcpServer.py
new file mode 100644
index 0000000..2a325eb
--- /dev/null
+++ b/select/TcpServer.py
@@ -0,0 +1,58 @@
+import socket
+import select
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+sock.bind(('', 8881))
+sock.listen(5)
+
+# lists of sockets to watch for input and output events
+ins = [sock]
+ous = []
+# mapping socket -&gt; data to send on that socket when feasible
+data = {}
+# mapping socket -&gt; (host, port) on which the client is running
+adrs = {}
+
+try:
+    while True:
+        i, o, e = select.select(ins, ous, [])  # no excepts nor timeout
+        for x in i:
+            if x is sock:
+                # input event on sock means client trying to connect
+                newSocket, address = sock.accept(  )
+                print "Connected from", address
+                ins.append(newSocket)
+                adrs[newSocket] = address
+            else:
+                # other input events mean data arrived, or disconnections
+                newdata = x.recv(8192)
+                if newdata:
+                    # data arrived, prepare and queue the response to it
+                    print "%d bytes from %s" % (len(newdata), adrs[x])
+                    data[x] = data.get(x, '') + newdata
+                    if x not in ous: ous.append(x)
+                else:
+                    # a disconnect, give a message and clean up
+                    print "disconnected from", adrs[x]
+                    del adrs[x]
+                    try: ous.remove(x)
+                    except ValueError: pass
+                    x.close(  )
+        for x in o:
+            # output events always mean we can send some data
+            tosend = data.get(x)
+            if tosend:
+                nsent = x.send(tosend)
+                print "%d bytes to %s" % (nsent, adrs[x])
+                # remember data still to be sent, if any
+                tosend = tosend[nsent:]
+            if tosend: 
+                print "%d bytes remain for %s" % (len(tosend), adrs[x])
+                data[x] = tosend
+            else:
+                try: del data[x]
+                except KeyError: pass
+                ous.remove(x)
+                print "No data currently remain for", adrs[x]
+finally:
+    sock.close(  )
+