Python || Snippet – How To Send Text Over A Network Using Socket, Send, & Recv

January 08, 2014 admin No comments

The following is sample code which demonstrates the use of the “socket“, “connect“, “send“, and “recv” function calls for interprocess communication over a network.

The following example demonstrates a simple network application in which a client sends text to a server, and the server replies (sends text) back to the client.

Note: The server program must be ran before the client program!

=== 1. SERVER ===





		
		
			IPC Networking - Server
			
Python
			
			# =============================================================================
#   Author: Kenneth Perkins
#   Date:  Jan 8, 2014
#   Taken From: http://programmingnotes.org/
#   File: Server.py
#   Description: This program implements a simple network application in
#     which a client sends text to a server and the server replies back to the
#     client. This is the server program, which has the following functionality:
#       1. Listen for incoming connections on a specified port.
#       2. When a client tries to connect, the connection is accepted.
#       3. When a connection is created, text is received from the client.
#       4. Text is sent back to the client from the server.
#       5. Close the connection and go back to waiting for more connections.
# =============================================================================
import socket, sys, datetime

# Run
# python3 Server.py 1234

# the client message size
MAX_MSG_LEN = 4096

def main(argc, argv):
    # check the command line arguments
    if(argc < 2):
        print("\n** ERROR NOT ENOUGH ARGS!\n"
            "USAGE: %s <SERVER PORT #>\n" %(argv[0]))
        sys.exit(1)

    # get the port number
    port = int(argv[1])

    # the backlog
    backlog = 100

    # create A TCP socket
    listenSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # bind the socket to the port
    listenSocket.bind(("", port))

    # start listening for incoming connections
    listenSocket.listen(backlog)

    print("\nServer started!")

    # service clients forever
    while(True):
        print("\nWaiting for someone to connect..")

        # accept a connection from the client
        client, address = listenSocket.accept()

        # get the data from the client
        data = client.recv(MAX_MSG_LEN)
        print("\nRECEIVED: '%s' from the client" %(data.decode("UTF-8")))

        # make sure the data was successfully received
        if(data):
            # get the current date and time
            now = datetime.datetime.now()
            dateAndTime = now.strftime("%a, %b %d %Y, %I:%M:%S %p")

            # send the date and time to the client
            print("\nSENDING: '%s' to the client" %(dateAndTime))
            client.send(dateAndTime.encode("UTF-8"))

        # close the connection to the client
        client.close()

if __name__ == "__main__":
    main(len(sys.argv), sys.argv)
# http://programmingnotes.org/
			
				
					
				
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						# =============================================================================
#   Author: Kenneth Perkins
#   Date:  Jan 8, 2014
#   Taken From: http://programmingnotes.org/
#   File: Server.py
#   Description: This program implements a simple network application in
#     which a client sends text to a server and the server replies back to the
#     client. This is the server program, which has the following functionality:
#       1. Listen for incoming connections on a specified port.
#       2. When a client tries to connect, the connection is accepted.
#       3. When a connection is created, text is received from the client.
#       4. Text is sent back to the client from the server.
#       5. Close the connection and go back to waiting for more connections.
# =============================================================================
import socket, sys, datetime
 
# Run
# python3 Server.py 1234
 
# the client message size
MAX_MSG_LEN = 4096
 
def main(argc, argv):
    # check the command line arguments
    if(argc < 2):
        print("\n** ERROR NOT ENOUGH ARGS!\n"
            "USAGE: %s <SERVER PORT #>\n" %(argv[0]))
        sys.exit(1)
 
    # get the port number
    port = int(argv[1])
 
    # the backlog
    backlog = 100
 
    # create A TCP socket
    listenSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
    # bind the socket to the port
    listenSocket.bind(("", port))
 
    # start listening for incoming connections
    listenSocket.listen(backlog)
 
    print("\nServer started!")
 
    # service clients forever
    while(True):
        print("\nWaiting for someone to connect..")
 
        # accept a connection from the client
        client, address = listenSocket.accept()
 
        # get the data from the client
        data = client.recv(MAX_MSG_LEN)
        print("\nRECEIVED: '%s' from the client" %(data.decode("UTF-8")))
 
        # make sure the data was successfully received
        if(data):
            # get the current date and time
            now = datetime.datetime.now()
            dateAndTime = now.strftime("%a, %b %d %Y, %I:%M:%S %p")
 
            # send the date and time to the client
            print("\nSENDING: '%s' to the client" %(dateAndTime))
            client.send(dateAndTime.encode("UTF-8"))
 
        # close the connection to the client
        client.close()
 
if __name__ == "__main__":
    main(len(sys.argv), sys.argv)
# http://programmingnotes.org/

=== 2. CLIENT ===





		
		
			IPC Networking - Client
			
Python
			
			# =============================================================================
#   Author: Kenneth Perkins
#   Date:  Jan 8, 2014
#   Taken From: http://programmingnotes.org/
#   File: Client.py
#   Description: This program implements a simple network application in
#     which a client sends text to a server and the server replies back to the
#     client. This is the client program, which has the following functionality:
#       1. Establish a connection to the server.
#       2. Send text to the server.
#       3. Recieve text from the server.
#       4. Close the connection and exit.
# =============================================================================
import socket, sys

# Run
# python3 Client.py localhost 1234

# the size of the message sent by server
MAX_MSG_LEN = 4096

def main(argc, argv):
    # check the command line arguments
    if(argc < 3):
        print("\n** ERROR NOT ENOUGH ARGS!\n"
            "USAGE: %s <SERVER IP> <SERVER PORT #>\n" %(argv[0]))
        sys.exit(1)

    # get the host name (or IP)
    host = argv[1]

    # get the server's port number
    port = int(argv[2])

    # the client socket
    clientSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # connect to the server
    clientSocket.connect((host,port))

    # send a string to the server
    data = "Server, what time is it?"
    print("\nSENDING: '%s' to the server" %(data))
    clientSocket.send(data.encode("UTF-8"))

    # get the date from the server
    data = clientSocket.recv(MAX_MSG_LEN)
    print("\nRECEIVED: '%s' from the server\n" %(data.decode("UTF-8")))

    # close the connection to the server
    clientSocket.close()

if __name__ == "__main__":
    main(len(sys.argv), sys.argv)
# http://programmingnotes.org/
			
				
					
				
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						# =============================================================================
#   Author: Kenneth Perkins
#   Date:  Jan 8, 2014
#   Taken From: http://programmingnotes.org/
#   File: Client.py
#   Description: This program implements a simple network application in
#     which a client sends text to a server and the server replies back to the
#     client. This is the client program, which has the following functionality:
#       1. Establish a connection to the server.
#       2. Send text to the server.
#       3. Recieve text from the server.
#       4. Close the connection and exit.
# =============================================================================
import socket, sys
 
# Run
# python3 Client.py localhost 1234
 
# the size of the message sent by server
MAX_MSG_LEN = 4096
 
def main(argc, argv):
    # check the command line arguments
    if(argc < 3):
        print("\n** ERROR NOT ENOUGH ARGS!\n"
            "USAGE: %s <SERVER IP> <SERVER PORT #>\n" %(argv[0]))
        sys.exit(1)
 
    # get the host name (or IP)
    host = argv[1]
 
    # get the server's port number
    port = int(argv[2])
 
    # the client socket
    clientSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
    # connect to the server
    clientSocket.connect((host,port))
 
    # send a string to the server
    data = "Server, what time is it?"
    print("\nSENDING: '%s' to the server" %(data))
    clientSocket.send(data.encode("UTF-8"))
 
    # get the date from the server
    data = clientSocket.recv(MAX_MSG_LEN)
    print("\nRECEIVED: '%s' from the server\n" %(data.decode("UTF-8")))
 
    # close the connection to the server
    clientSocket.close()
 
if __name__ == "__main__":
    main(len(sys.argv), sys.argv)
# http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

The following is sample output.

SERVER OUTPUT:

Server started!
Waiting for someone to connect.. RECEIVED: "Server, what time is it?" from the client
SENDING: "Wed, Jan 08 2014, 04:02:13 PM" to the client

CLIENT OUTPUT:

SENDING: "Server, what time is it?" to the server
RECEIVED: "Wed, Jan 08 2014, 04:02:13 PM" from the server

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Posted in: Console, Python, Python, Snippets Tags: cpsc 471, ipc, networking, recv, send, socket

Python || Snippet – How To Send Text Over A Network Using Socket, Send, & Recv

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