Prerequisite : Socket Programming in Python, Multi-threading in Python
Socket Programming-> It helps us to connect a client to a server. Client is message sender and receiver and server is just a listener that works on data sent by client.
What is a Thread?
A thread is a light-weight process that does not require much memory overhead, they are cheaper than processes.
What is Multi-threading Socket Programming? port on your computer
Multithreading is a process of executing multiple threads simultaneously in a single process.
Multi-threading Modules :
A _thread module & threading module is used for multi-threading in python, these modules help in synchronization and provide a lock to a thread in use.
from _thread import * import threading
A lock object is created by->
print_lock = threading.Lock()
A lock has two states, “locked” or “unlocked”. It has two basic methods acquire() and release(). When the state is unlocked print_lock.acquire() is used to change state to locked and print_lock.release() is used to change state to unlock.
The function thread.start_new_thread() is used to start a new thread and return its identifier. The first argument is the function to call and its second argument is a tuple containing the positional list of arguments.
Let’s study client-server multithreading socket programming by code-
Note:-The code works with python3.
Multi-threaded Server Code
Python3
# import socket programming libraryimport socket# import thread modulefrom _thread import *import threadingprint_lock = threading.Lock()# thread functiondef threaded(c): while True: # data received from client data = c.recv(1024) if not data: print('Bye') # lock released on exit print_lock.release() break # reverse the given string from client data = data[::-1] # send back reversed string to client c.send(data) # connection closed c.close()def Main(): host = "" # reserve a port on your computer # in our case it is 12345 but it # can be anything port = 12345 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.bind((host, port)) print("socket binded to port", port) # put the socket into listening mode s.listen(5) print("socket is listening") # a forever loop until client wants to exit while True: # establish connection with client c, addr = s.accept() # lock acquired by client print_lock.acquire() print('Connected to :', addr[0], ':', addr[1]) # Start a new thread and return its identifier start_new_thread(threaded, (c,)) s.close()if __name__ == '__main__': Main() |
Console Window: socket binded to port 12345 socket is listening Connected to : 127.0.0.1 : 11600 Bye
Client Code
Python
# Import socket moduleimport socketdef Main(): # local host IP '127.0.0.1' host = '127.0.0.1' # Define the port on which you want to connect port = 12345 s = socket.socket(socket.AF_INET,socket.SOCK_STREAM) # connect to server on local computer s.connect((host,port)) # message you send to server message = "shaurya says neveropen" while True: # message sent to server s.send(message.encode('ascii')) # message received from server data = s.recv(1024) # print the received message # here it would be a reverse of sent message print('Received from the server :',str(data.decode('ascii'))) # ask the client whether he wants to continue ans = input('\nDo you want to continue(y/n) :') if ans == 'y': continue else: break # close the connection s.close()if __name__ == '__main__': Main() |
Console Window: Received from the server : skeegrofskeeg syas ayruahs Do you want to continue(y/n) :y Received from the server : skeegrofskeeg syas ayruahs Do you want to continue(y/n) :n Process finished with exit code 0
Reference->
https://docs.python.org/2/library/thread.html
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