Re: Socket and cycle problem
- From: petr.poupa@xxxxxxxxx
- Date: Tue, 13 May 2008 10:41:43 -0700 (PDT)
On 12 Kvě, 21:06, Jean-Paul Calderone <exar...@xxxxxxxxxx> wrote:
On Mon, 12 May 2008 11:16:08 -0700 (PDT), petr.po...@xxxxxxxxx wrote:
[snip]
My script send me via 3883 port (VRPN) data, but only once. I need
listening this port countinously.
So I need make some loop to print data from 3883 port permanent.
Data that I recevied looks liek this:
receive data from server: 'vrpn: ver. 07.13 0\x00\xe8\x0b\x00\x00'
I'm not sure if you need to write a server or a client. In your
original code, you had a client which repeatedly established out-
bound connections. Here, you say you need to listen on a port.
Do you think its necessary to use Twisted? Do you have any ideas how
to do it with socket modul?
The basic version is pretty easy either way. However, with Twisted,
you get cross-platform error handling without any extra effort, and
you don't have to think about the boring low-level details of BSD
sockets.
Here's a Twisted server that listens on port 3883 forever and prints
the data it receives from each connection after the remote side drops
the connection:
from twisted.internet import reactor
from twisted.internet.protocol import ServerFactory, Protocol
class PrintingProtocol(Protocol):
def connectionMade(self):
"""
When the connection is first established, create a list
into which to buffer all received data.
"""
self.received = []
def dataReceived(self, data):
"""
Whenever any data is received on this connection, add it
to the buffer.
"""
self.received.append(data)
def connectionLost(self, reason):
"""
When the connection is lost, print out the contents of
the receive buffer.
"""
print repr("".join(self.received))
# Create a factory which will use our protocol to handle incoming
# connections.
factory = ServerFactory()
factory.protocol = PrintingProtocol
# Listen with it on port 3883
reactor.listenTCP(3883, factory)
# Start the reactor. Nothing in this program will ever stop the
# reactor, so it will run and accept connections forever.
reactor.run()
If you were to use the socket module, then it would look something like this:
from socket import socket
from errno import EINTR
port = socket()
port.bind(('', 3883))
port.listen(5)
while True:
try:
server, clientAddr = port.accept()
except socket.error, e:
print "Error accepting client connection", e
else:
received = []
while True:
try:
bytes = server.recv(1024 * 16)
except socket.error, e:
if e.errno == EINTR:
continue
else:
break
if not bytes:
break
received.append(bytes)
print repr("".join(received))
Hope this helps,
Jean-Paul
Thanks for code. I am trying both of them, but I am crash to another
problem.
For socket modul example python report:
Traceback (most recent call last):
File "C:\Documents and Settings\poupa\Plocha\listen2.py", line 5, in
<module>
port.bind(('', 3883))
File "<string>", line 1, in bind
error: (10048, 'Address already in use')
and for twisted example pythod report:
Traceback (most recent call last):
File "C:\Documents and Settings\poupa\Plocha\listen2twisted.py",
line 8, in -toplevel-
class PrintingProtocol(Protocol):
File "C:\Documents and Settings\poupa\Plocha\listen2twisted.py",
line 28, in PrintingProtocol
print repr("".join(self.received))
NameError: name 'self' is not defined
How can I solve this errors?
(for twisted I instal zope for python, pywin32 and twisted. all for
python 2.4)
.
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