I am having some problems adding in a logging file for my python TCP server code.
I've looked at some examples, but as I don't have much experience in writing my own scripts/codes, I'm not very sure how to go about doing this. I would appreciate if someone could guide me in the right direction with explanation and some examples if possible.
I am using HERCULES SETUP UTILITY , which acts as my TCP client, while my visual studio python code acts as a SERVER. My SERVER can receive the data which is sent by the client by now , I just can't seem to add in a logging file which can save the sent data into text file.Can someone please show me some examples or referance please? Your help would mean alot. This is my code so far :
from socket import *
import thread
BUFF = 1024 # buffer size
HOST = '172.16.166.206'# IP address of host
PORT = 1234 # Port number for client & server to recieve data
def response(key):
return 'Sent by client'
def handler(clientsock,addr):
while 1:
data = clientsock.recv(BUFF) # receive data(buffer).
print 'data:' + repr(data) #Server to recieve data sent by client.
if not data: break #If connection is closed by client, server will break and stop recieving data.
print 'sent:' + repr(response('')) # respond by saying "Sent By Client".
if __name__=='__main__':
ADDR = (HOST, PORT) #Define Addr
serversock = socket(AF_INET, SOCK_STREAM)
serversock.bind(ADDR) #Binds the ServerSocket to a specific address (IP address and port number)
serversock.listen(0)
while 1:
print 'waiting for connection...'
clientsock, addr = serversock.accept()
print '...connected from:', addr #show its connected to which addr
thread.start_new_thread(handler, (clientsock, addr ))
In context, maybe something like this?
#!/usr/local/cpython-2.7/bin/python
import socket
import thread
BUFF = 1024 # buffer size
HOST = '127.0.0.1'
PORT = 1234 # Port number for client & server to recieve data
def response(key):
return 'Sent by client'
def logger(string, file_=open('logfile.txt', 'a'), lock=thread.allocate_lock()):
with lock:
file_.write(string)
file_.flush() # optional, makes data show up in the logfile more quickly, but is slower
def handler(clientsock, addr):
while 1:
data = clientsock.recv(BUFF) # receive data(buffer).
logger('data:' + repr(data) + '\n') #Server to recieve data sent by client.
if not data:
break #If connection is closed by client, server will break and stop recieving data.
logger('sent:' + repr(response('')) + '\n') # respond by saying "Sent By Client".
if __name__=='__main__':
ADDR = (HOST, PORT) #Define Addr
serversock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversock.bind(ADDR) #Binds the ServerSocket to a specific address (IP address and port number)
serversock.listen(0)
while 1:
logger('waiting for connection...\n')
clientsock, addr = serversock.accept()
logger('...connected from: ' + str(addr) + '\n') #show its connected to which addr
thread.start_new_thread(handler, (clientsock, addr))
HTH
It sounds to me like your question would be better rephrased as “How do I read and write files within Python?”.
This is something well documented at: http://docs.python.org/2.7/tutorial/inputoutput.html#reading-and-writing-files
Example:
f = open('/tmp/log.txt', 'a')
f.write('Doing something')
do_something()
f.write('Other stuff')
other_stuff()
f.write('All finished')
f.close()
Related
I want to make a server, which receives messages from smartphones and based on them, sends messages to one specific IP and port. but when I define two IPs (one for the server and another to send messages) gives the error that I cannot use the socket more than ONE time. I am not a programmer, so please help me correct my code.
import socket
import time
host = '192.168.100.41' #Define a server to receive messages
port = 5000
s = socket.socket()
s.bind((host,port))
s.listen(1)
c, addr = s.accept()
print ("Connection from: ")
while True:
Buffer = c.recv(1024)
if not data:
break
address = ( '192.168.100.60', 5555) #Defind Destination address to send a message (must match destination IP and port)
client_socket = socket(AF_INET, SOCK_DGRAM) #Set Up the Socket
client_socket.settimeout(1) #only wait 1 second for a resonse
def ON(evt):
data = "1ON" #Set data
client_socket.sendto(data, address) #send command
try:
rec_data, addr = client_socket.recvfrom(2048) #Read response
print (rec_data) #Print the response
except:
pass
Here is my server code.
# chat_server.py
import sys, socket, select
HOST = ''
SOCKET_LIST = []
RECV_BUFFER = 4096
PORT = 9009
def chat_server():
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind((HOST, PORT))
server_socket.listen(10)
# add server socket object to the list of readable connections
SOCKET_LIST.append(server_socket)
print "Chat server started on port " + str(PORT)
while 1:
# get the list sockets which are ready to be read through select
# 4th arg, time_out = 0 : poll and never block
ready_to_read,ready_to_write,in_error = select.select(SOCKET_LIST,[],[],0)
for sock in ready_to_read:
# a new connection request recieved
if sock == server_socket:
sockfd, addr = server_socket.accept()
SOCKET_LIST.append(sockfd)
print "Client (%s, %s) connected" % addr
broadcast(server_socket, sockfd, "[%s:%s] entered our chatting room\n" % addr)
# a message from a client, not a new connection
else:
# process data recieved from client,
try:
# receiving data from the socket.
data = sock.recv(RECV_BUFFER)
if data:
# there is something in the socket
broadcast(server_socket, sock, "\r" + '[' + str(sock.getpeername()) + '] ' + data)
else:
# remove the socket that's broken
if sock in SOCKET_LIST:
SOCKET_LIST.remove(sock)
# at this stage, no data means probably the connection has been broken
broadcast(server_socket, sock, "Client (%s, %s) is offline\n" % addr)
# exception
except:
broadcast(server_socket, sock, "Client (%s, %s) is offline\n" % addr)
continue
server_socket.close()
# broadcast chat messages to all connected clients
def broadcast (server_socket, sock, message):
for socket in SOCKET_LIST:
# send the message only to peer
if socket != server_socket and socket != sock :
try :
socket.send(message)
except :
# broken socket connection
socket.close()
# broken socket, remove it
if socket in SOCKET_LIST:
SOCKET_LIST.remove(socket)
if __name__ == "__main__":
sys.exit(chat_server())
Here is my client code.
# chat_client.py
import sys, socket, select
def chat_client():
if(len(sys.argv) < 3) :
print 'Usage : python chat_client.py hostname port'
sys.exit()
host = sys.argv[1]
port = int(sys.argv[2])
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(2)
# connect to remote host
try :
s.connect((host, port))
except :
print 'Unable to connect'
sys.exit()
# TEST
person = raw_input ('Please enter your username: ')
print 'Connected to remote host. You can start sending messages.'
sys.stdout.write( person + '[Me]: ' ); sys.stdout.flush()
while 1:
socket_list = [sys.stdin, s]
# Get the list sockets which are readable
read_sockets, write_sockets, error_sockets = select.select(socket_list , [], [])
for sock in read_sockets:
if sock == s:
# incoming message from remote server, s
data = sock.recv(4096)
if not data :
print '\nDisconnected from chat server'
sys.exit()
else :
#print data
sys.stdout.write(data)
sys.stdout.write( person + '[Me]: '); sys.stdout.flush()
else :
# user entered a message
msg = sys.stdin.readline()
s.send(msg)
sys.stdout.write( person + '[Me]: '); sys.stdout.flush()
if __name__ == "__main__":
sys.exit(chat_client())
I'm currently trying to work on adding sort of a "handle" system into the chat client. If you were to run this code, you'll notice that the handle you choose is only displayed on your client, and not anybody else's. I've done hours of research already, and I can't for the life of me figure out how to have a client's chosen handle displayed onto other clients.
I'm still relatively new to Python, and especially new to TCP/IP programming. Any help, advice, and constructive criticism will be welcomed. Thanks in advance!
You can do it on the server or the client side
Server side
To implement it server side, you need to maintain some kind of mapping in the server between client sockets and handles, so that when you broadcast a message from a socket, you can retrieve its handle and prepend it to the message before sending.
In order to know the handle of the clients, they can send it to the server as the first message when they connect. The server will interpret this first message as the handle, and store it mapping it to the socket from what it has been received.
The advantage of this approach is that the server can validate the handle before it accepts it from the clients, and if it is already in use, reject the handle or abort the connection. Also, the clients cannot fake their handle later in the conversation, as it is the server that sends them.
Client side
This is the easiest implementation, as you only need to modify the client and prepend the handle before sending each message.
# user entered a message
msg = sys.stdin.readline()
s.send(person + ": " + msg)
sys.stdout.write( person + '[Me]: '); sys.stdout.flush()
The drawbacks of this approach are that a malicious client can fake the handle to pretend to be another person, and that two clients can have the same handle at the same time, making them indistinguishable from each other.
I'm struggling with the .sendall() method for a client/server -setup. Several clients can connect individually and send messages to the server and get the echoed response. However, I expect the messages sent to show up for all the connected clients in a chat-like Environment.
This is the code running on the server application.
def clientHandler(conn, addr):
name = addr[0]
print(addr, " connected to the server")
while True:
data = conn.recv(1024)
if tostr(data)[0:5] == '/name':
print('setting name')
setname(data)
if not data:
break
conn.sendall(str.encode(checkname(addr[0]) + tostr(data)))
print('Received Message: ', tostr(data))
HOST = '' #LOCALHOST
PORT = 1400
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind((HOST, PORT))
sock.listen(999999)
print('Server is running' + '-'*10)
for i in range(999999):
conn, addr = sock.accept()
Thread(target = clientHandler, args = (conn, addr)).start()
sock.close()
Thank you in advance
As I had originally said in a comment (but now decided is better said in an answer), sendall sends all bytes to a single connection. You need to add something like:
lock = threading.Lock()
all_clients = []
at the top; in the main loop, where you now have just conn, addr = sock.accept(), have
conn, addr = sock.accept()
with lock:
all_clients.append(conn)
In clientHandler, where you now have just conn.sendall(str.encode(checkname(addr[0]) + tostr(data))), have instead
with lock:
for c in all_clients:
c.sendall(str.encode(checkname(addr[0]) + tostr(data)))
IOW, you need to explicitly code the "broadcast" business logic in your server -- it's absolutely not implicit in sendall (whose semantics you may have misunderstood).
I have simple python server and client.
Server:
import SocketServer
import threading
class MyTCPHandler(SocketServer.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
print str(self.client_address[0]) + " wrote: "
print self.data
self.request.send(self.data.upper())
if __name__ == "__main__":
HOST, PORT = "localhost", 3288
server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler)
server.serve_forever()
Client:
import socket
import sys
from time import sleep
HOST, PORT = "localhost", 3288
data = "hello"
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((HOST, PORT))
sock.send(data + "\n")
received = sock.recv(1024)
sleep(10)
sock.send(data + "\n")
received = sock.recv(1024)
sleep(10)
sock.send(data + "\n")
received = sock.recv(1024)
finally:
sock.close()
Here is the output I get:
Server:
>python server.py
127.0.0.1 wrote:
hello
Client:
>python client.py
Traceback (most recent call last):
File "client.py", line 18, in <module>
received = sock.recv(1024)
socket.error: [Errno 10053] An established connection was aborted by the software in your host machine
I tried it on a linux machine as well. The server only receives one message and then I get an error on the recv statement of second message. I have just started learning networking on python but I think the server is closing the socket for some reason. How do I correct this?
A MyTcpHandler object is created for each connection, and handle is called to deal with the client. The connection is closed when handle returns, so you have to handle the complete communication from the client within the handle method:
class MyTCPHandler(SocketServer.BaseRequestHandler):
def handle(self):
while 1:
self.data = self.request.recv(1024)
if not self.data:
break
self.data = self.data.strip()
print str(self.client_address[0]) + " wrote: "
print self.data
self.request.send(self.data.upper())
NOTE: recv returns '' when the client closes the connection, so I moved .strip() after the recv so there is no false alarm due to the client sending only white space.
I'll first admit that it's been years since I last used SocketServer, so there might be more idiomatic approaches to solve your problem.
Note that your client opens a single connection and sends three sets of data and receives three sets of data. (Hopefully the TCP stack will send buffered data once you call receive() on the socket.)
Your server is expecting to handle a client connection completely, from start to finish, when it is called from the SocketServer callback mechanism. Your current class does a little bit of IO and then quits. You just need to extend your server callback to do more:
class MyTCPHandler(SocketServer.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
print str(self.client_address[0]) + " wrote: "
print self.data
self.request.send(self.data.upper())
foo = self.request.recv(1024).strip()
self.request.send(foo.lower())
bar = self.request.recv(1024).strip()
self.request.send("goodbye " + bar)
TO a similar problem here error: [Errno 10053]
I also tried the same thing and got the same error.
If there is a simple code like this to demonstrate this error:
import socket
host = 'localhost'
port = 5001
size = 102400
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
for msg in ['Hello, world','Test','anything goes here']:
s.send(msg)
data = s.recv(size)
print 'Received:', data
s.close()
If you create a socket object and the amt it can send and echo back from server to see how much it receivers, if you vary that, say 1024 to 102400(in this code);
Which means the socket should not get closed but again in my Windows OS, the server side keeps listening and printing any data that client sends but on the Client side you get this error;
However if it is that the client can connect only once and send and receive only once, then that is how it was designed. Trying this works without any errors:
for msg in ['Hello, world','Test','anything goes here']:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host,port))
s.send(msg)
data = s.recv(size)
s.close()
print 'Received:', data
I am not sure if one socket object works only once to send and recieve data.
UPDATE
I think the issue was the capacity per client socket to receive data as per the buffersize fixed;
That's why the second code snippet above works thus creating new client connection sockets on the server. But that way lots of sockets are going to get used up.
Instead the following code fixed that problem by checking the amt of size being used up. If it exceeds the given amount, it creates a new socket at clients' but makes sure the message is sent; Actually the problem was with the server code but fixed it.
size = 10
This is a quick baby attempt at the code. I am sure you would understand and optimize it for the better!
client code:
messag = ['Hello, world', 'Test', 'anything goes here']
def client_to_server(messag,host,port,size):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
countmsg = 0
restmsg = ''
for msg in messag:
strl = tmsg = msg
if len(restmsg):
tmsg = restmsg + ' ' + msg
countmsg = len(tmsg)
if countmsg <= size:
pass
else:
restmsg = tmsg[size:]
tmsg = tmsg[:size]
#s.close()
countmsg = len(tmsg)
#s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
#s.connect((host, port))
print 'Sending to server msg {}'.format(tmsg)
s.send(tmsg)
# s.settimeout(1)
try:
data = s.recv(size)
print 'Received:', data
if strl == data:
print strl,data
countmsg = 0
restmsg = ''
except (socket.error), e:
print e.args,e.message
s.close()
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
s.close()
if restmsg:
client_to_server([restmsg],host,port,size)
return
client_to_server(messag,host,port,size)
Server Code:
size = 1024 #This has to be bigger than client buf size!
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host, port))
s.listen(backlog)
while True:
#this is what accepts and creates a P2P dedicated client socket per socket
client, address = s.accept()
try:
data = client.recv(size)
while data or 0:
print "Client sent {} | Server sending data to client address {}".format(data, address)
client.send(data)
data = client.recv(size)
else: client.close()
except (socket.error), e:
client.close()
print e.args, e.message
Try it out. This uses the same socket.
I am implementing a program with a server and multiple clients. All clients send data to the server and a server check out the step of each client. If all client's steps are the same, a server sends new data to all clients to do next step. And it continues this procedure again and again.
However, when I run my program, it cannot communicate each other. Here are my code. Would you give me some hints?
client & server
#client
from socket import *
from sys import *
import time
import stat, os
import glob
# set the socket parameters
host = "localhost"
port = 21567
buf = 1024
data = ''
addr = (host, port)
UDPSock = socket(AF_INET, SOCK_DGRAM)
UDPSock.settimeout(100)
def_msg = "=== TEST ==="
#FILE = open("test.jpg", "w+")
FILE = open("data.txt","w+")
while (1):
#data, addr = UDPSock.recvfrom(buf)
print "Sending"
UDPSock.sendto(def_msg, addr)
#time.sleep(3)
data, addr = UDPSock.recvfrom(buf)
if data == 'done':
FILE.close()
break
FILE.write(data)
print "Receiving"
#time.sleep(3)
UDPSock.close()
# server program for nvt
from socket import *
import os, sys, time, glob
#import pygame
import stat
host = 'localhost'
port = 21567
buf = 1024
addr = (host, port)
print 'test server'
UDPSock = socket(AF_INET, SOCK_DGRAM)
UDPSock.bind(addr)
msg = "send txt file to all clients"
#FILE = open("cam.jpg", "r+")
FILE = open("dna.dat","r+")
sending_data = FILE.read()
FILE.close()
tmp_data = sending_data
while (1):
#UDPSock.listen(1)
#UDPSock.sendto(msg, addr)
#FILE = open("gen1000.dat","r+")
#sending_data = FILE.read()
#FILE.close()
#print 'client is at', addr
data, addr = UDPSock.recvfrom(buf)
#time.sleep(3)
print data
#msg = 'hello'
#
tmp, sending_data = sending_data[:buf-6], sending_data[buf-6:]
if len(tmp) < 1:
msg = 'done'
UDPSock.sendto(msg, addr)
print "finished"
sending_data = tmp_data
UDPSock.sendto(tmp, addr)
print "sending"
#time.sleep(3)
UDPSock.close()
A server must perform the sequence socket(), bind(), listen(), accept() (possibly repeating the accept() to service more than one client), while a client only needs the sequence socket(), connect().
Your missing listen() i saw first. Listen for connections made to the socket.
More on this here: link text
Look at this: http://heather.cs.ucdavis.edu/~matloff/Python/PyNet.pdf
It's a very good Python networking tutorial including working examples of a client and server. Now, I'm not an expert on this, but it looks to me like your code is overcomplicated. And what's the deal with all the commented-out lines?
Quote from question:
#UDPSock.listen(1)
#UDPSock.sendto(msg, addr)
#FILE = open("gen1000.dat","r+")
#sending_data = FILE.read()
#FILE.close()
End quote
Those look like some pretty important lines to me.
Also, make sure the computers are connected. From a prompt run:
ping [IP]
where [IP] is the IP address of the other machine(Note: if you're not connected to the same LAN, this becomes much harder as you might then need port forwarding and possibly static IPs).