I am wondering if there is any way to wirelessly connect to a computer/server using python's socket library. The dir(socket) brought up a lot of stuff and I wanted help sorting it out.
but one question. Is the socket server specific to python, or can
another language host and python connect or vise-versa?
As long as you are using sockets - you can connect to any socket-based server (made with any language). And vice-versa: any socket-based client will be able to connect to your server. Moreover it's cross-platform: socket-based client from any OS can connect to any socket-based server (from any OS).
It is unclear of what you mean by "Connect to a computer" so I gave you a TCP socket server and client.
Create a socket server on the computer you wish to "connect to" with:
import SocketServer
class MyTCPHandler(SocketServer.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
print "{} wrote:".format(self.client_address[0])
print self.data
self.request.sendall(self.data.upper())
if __name__ == "__main__":
HOST, PORT = "localhost", 9999
# Create the server, binding to localhost on port 9999
server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler)
server.serve_forever()
Now create the client:
import socket
import sys
HOST, PORT = "localhost", 9999
data = " ".join(sys.argv[1:])
(SOCK_STREAM means a TCP socket)
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((HOST, PORT))
sock.sendall(data + "\n")
received = sock.recv(1024)
finally:
sock.close()
print "Sent: {}".format(data)
print "Received: {}".format(received)
You run the server and then the client and the server should receive the client's connection and send it whatever you have as the data variable on the server. Source: https://docs.python.org/2/library/socketserver.html
Related
I am trying to get this simple python3 code to run in docker using sockets, but I receive the following error. Can someone point me in the right direction. I am just trying to get it to work so i can integrate it into my broader project
File "registrar.py", line 29, in <module>
with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server:
AttributeError: __exit__
Server
import socketserver
import json
list_of_nodes = []
class MyTCPHandler(socketserver.BaseRequestHandler):
"""
The request handler class for our server.
It is instantiated once per connection to the server, and must
override the handle() method to implement communication to the
client.
"""
def handle(self):
global list_of_nodes
# self.request is the TCP socket connected to the client
self.data = self.request.recv(1024).strip()
print("{} wrote:".format(self.client_address[0]))
print(json.loads(self.data))
# just send back the same data, but upper-cased
list_of_nodes.append(json.loads(self.data))
self.request.sendall(bytes(str(len(list_of_nodes)-1), 'utf-8'))
print(list_of_nodes)
if __name__ == "__main__":
HOST, PORT = "localhost", 58333
# Create the server, binding to localhost on port 9999
with socketserver.TCPServer((HOST, PORT), MyTCPHandler) as server:
# Activate the server; this will keep running until you
# interrupt the program with Ctrl-C
server.serve_forever()
Client
import socket
import sys
import time
import json
HOST, PORT = "localhost", 58333
data = " ".join(sys.argv[1:])
dict_node = {'nVersion': 1,
'nTime': time.time(),
'addrMe': socket.gethostbyname(socket.gethostname())
}
# Create a socket (SOCK_STREAM means a TCP socket)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
# Connect to server and send data
sock.connect((HOST, PORT))
json_msg = json.dumps(dict_node)
sock.sendall(bytes(json_msg, "utf-8"))
# Receive data from the server and shut down
received = str(sock.recv(1024), "utf-8")
print("Sent: {}".format(json_msg))
print("Received: {}".format(json.loads(received)))
I'm trying use the python socket module to connect to an ngrok server. If I put the ngrok into my browser it connects properly so the problem is somewhere with my client code. Here is the server code:
#server.py
import socketserver
class MyTCPHandler(socketserver.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
print("{} wrote:".format(self.client_address[0]))
print(self.data)
if __name__ == "__main__":
HOST, PORT = "192.168.86.43", 8080
server = socketserver.TCPServer((HOST, PORT), MyTCPHandler)
server.serve_forever()
And here is the client:
#client.py
import socket
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.connect(("http://urlhere.ngrok.io", 8080))
sock.sendall(bytes("Hello" + "\n", "utf-8"))
Thanks!
In general you should be able to connect to any globally available address or DNS name, ensuring there is no network restrictions on the way. However you have to listen on the address that is locally available for global routing if you are communicating across the Internet.
As for particular code, there are 2 issues:
Socket should be connected to an address or DNS name. The protocol is defined with the socket type. In your case
import socket
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.connect(("localhost", 8080))
sock.sendall(bytes("Hello" + "\n", "utf-8"))
You're binding in the server to some speciffic not related address. To run your code you should bind to either localhost or to "any available" address "0.0.0.0":
import socketserver
class MyTCPHandler(socketserver.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
print("{} wrote:".format(self.client_address[0]))
print(self.data)
if __name__ == "__main__":
HOST, PORT = "0.0.0.0", 8080
server = socketserver.TCPServer((HOST, PORT), MyTCPHandler)
server.serve_forever()
I am setting up a basic TCP server for receiving local connections. I already have client applications with sockets constructed in the following way sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM). I need the client to be able to connect with these parameters even if they aren't required. Something about my very simple server does not allow this connection if those two params are passed in.
I have made sure that the IP and port are available on my computer. I have successfully connected a UDP client to a similar Handler with these parameters passed in. I have gotten a successful TCP connection by just constructing the client as sock = socket.socket() without parameters.
Server File:
class TCPHandler(SocketServer.BaseRequestHandler):
def handle(self):
self.data = self.request.recv(1024).strip()
self.request.sendall(self.data.upper())
...
#(in main)
server = SocketServer.TCPServer((HOST,PORT), TCPHandler)
print "TCP Server Started"
Client File:
try:
#sock = socket.socket()
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.settimeout(3.0)
print "Attempting to TCP connection"
PORT = 53140
sock.connect((HOST, PORT))
print "Connected to TCP"
sock.sendall(data + "\n")
received = sock.recv(1024)
sock.close()
except Exception as e:
print e
If I run the code as pasted I get a "Connection Refused" error. If I used the commented line instead, the TCP connection works.
I have a server that uses a thread to listen for new connections and then starts one thread for every client to serve him. Now, the server runs perfectly, but when a client connects it gives me the error in the title. I think because both client and server are trying to use the same port.
Here's the server code:
class ThreadedTCPRequestHandler(SocketServer.BaseRequestHandler):
def __init__(self, conne):
initialization
def handle(self):# "run"
does something
class ThreadedTCPServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
pass
HOST = '' # Symbolic name meaning all available interfaces
PORT = 1000 # Arbitrary non-privileged port
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(5)
n=1
while 1:
conn, addr = s.accept() # wait for a new connection. Get a new socket (conn) for each new connection
print 'Connected by', addr
server = ThreadedTCPServer((HOST, PORT), ThreadedTCPRequestHandler) #this line gives me the error
ip, port = server.server_address
server_thread = threading.Thread(target=server.serve_forever)
server_thread.setDaemon(True)
server_thread.setName('Client '+str(n))
server_thread.start() # Start the new thread
n+=1
server.shutdown()
server.server_close()
And here's the client:
import socket
HOST, PORT = "localhost", 1000
data = "0"
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
sock.connect((HOST, PORT))
sock.sendall(data)
received = sock.recv(1024)
finally:
sock.close()
print "Sent: {}".format(data)
print "Received: {}".format(received)
First you create server socket and bind it to port 1000. Then when client connects you receive a socket connected with client (conn, addr = s.accept()) that should be used to communicate with client but you completely ignore it. Instead you create another server that tried to bind again to port 1000. This results in "already used" error as expected.
I'd suggest you check this example of TcpServer threading and forking. Here a custom class derived from SocketServer.TCPServer is created initially (not a simple server socket as you do). It internally loops over accepting incoming client connections and for each connection calls specified SocketServer.BaseRequestHandler from a new thread or process (in case of forking) so you don't need to deal with them explicitly. Custom request handler just needs to, well, handle the request, potentially in a loop if communication with client is multi-step.
Be aware that thread/process per client approach doesn't scale well on large number of simultaneous client connections.
SocketServer Program
This code is in raspberry:
import SocketServer
class MyTCPHandler(SocketServer.BaseRequestHandler):
"""
The request handler class for our server.
It is instantiated once per connection to the server, and must
override the handle() method to implement communication to the
client.
"""
def handle(self):
# self.request is the TCP socket connected to the client
self.data = self.request.recv(1024).strip()
print "{} wrote:".format(self.client_address[0])
print self.data
# just send back the same data, but upper-cased
self.request.sendall(self.data)
if __name__ == "__main__":
HOST, PORT = "localhost", 9999
# Create the server, binding to localhost on port 9999
server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler)
# Activate the server; this will keep running until you
# interrupt the program with Ctrl-C
server.serve_forever()
Socket Client Program
This code is in my laptop:
import socket
import sys
HOST, PORT = "192.168.1.40", 3360
data='Hello'
#data = data.join(sys.argv[1:])
# Create a socket (SOCK_STREAM means a TCP socket)
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
# Connect to server and send data
sock.connect((HOST, PORT))
sock.sendall(data + "\n")
# Receive data from the server and shut down
received = sock.recv(1024)
finally:
sock.close()
print "Sent: {}".format(data)
print "Received: {}".format(received)
Here the data sent should be received to server and sent back to client.
This is the error:
[Errno 10061] No connection could be made because the target machine actively refused it.
Try changing to HOST, PORT = "0.0.0.0", 9999 in the server. Now the server should listen on all interfaces and not just the loopback interface. The same could also be achieved using an empty string i.e HOST, PORT = "", 9999.