Sockets
s = socket.socket (socket_family, socket_type, protocol=0) |
socket_family: This is either AF_UNIX or AF_INET, as explained earlier.
socket_type: This is either SOCK_STREAM or SOCK_DGRAM.
protocol: This is usually left out, defaulting to 0. |
AF_INET: TCPv4 or Hostname
SOCK_DGRAM: UDP
SOCK_STREAM: TCP |
Domain |
The family of protocols that is used as the transport mechanism. These values are constants such as AF_INET, PF_INET, PF_UNIX, PF_X25, and so on. |
Type |
The type of communications between the two endpoints, typically SOCK_STREAM for connection-oriented protocols and SOCK_DGRAM for connectionless protocols. |
protocol |
Typically zero, this may be used to identify a variant of a protocol within a domain and type. |
hostname |
The identifier of a network interface:
A string, which can be a host name, a dotted-quad address, or an IPV6 address in colon (and possibly dot) notation
A string "<broadcast>", which specifies an INADDR_BROADCAST address.
A zero-length string, which specifies INADDR_ANY, or
An Integer, interpreted as a binary address in host byte order. |
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Server Socket Methods
s.bind() |
This method binds address (hostname, port number pair) to socket. |
s.listen() |
This method sets up and start TCP listener. |
s.accept() |
This passively accept TCP client connection, waiting until connection arrives (blocking). |
Client Socket Method
s.connect() |
This method actively initiates TCP server connection. |
General Socket Method
s.recv() |
This method receives TCP message |
s.send() |
This method transmits TCP message |
s.recvfrom() |
This method receives UDP message |
s.sendto() |
This method transmits UDP message |
s.close() |
This method closes socket |
socket.gethostname() |
Returns the hostname. |
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Simple Server Example
#!/usr/bin/python # This is server.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
while True:
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
c.send('Thank you for connecting')
c.close() # Close the connection
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Simple Client Example
#!/usr/bin/python # This is client.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 12345 # Reserve a port for your service.
s.connect((host, port))
print s.recv(1024)
s.close # Close the socket when done
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