server.py

# The Server code for Serin
# Start at a terminal and point other nodes (serin.py) to this

import socket
import lib

# Opening Socket
#--------------------------
HOST = ''
PORT = 4444
lib.printSerin()

serv = lib.createListenerHere(HOST, PORT)
serv.listen(10)
print 'Socket Listening'
#--------------------------

# The variables to store file and sender info
filename = ''
sender = ''

# Transaction management
#--------------------------
while True:
	conn, adr = serv.accept()
	print 'Connected to ' + adr[0] + ':' + str(adr[1])
	data = conn.recv(1024)
	if data != '':
		# The client asks for state
		if data == 'status_of_server':
			print 'Client asked for state of server.'
			if filename == '':
				# The client is sender and is requested to give the file name.
				conn.sendall('send_file')
				print 'Asked client for file'
			else:
				# The client is receiver. File name and sender ip is sent to it.
				print 'Sent client the file details'
				conn.sendall(filename + ',' + sender)
				filename = ''
				sender = ''
		else:
			# The sender gives the file name.
			print 'Client sent the file name : ' + data
			if filename == '':
				conn.sendall('ok') # Informing sender that the file is noted for sending.
				filename = data
				sender = adr[0]

#--------------------------

conn.close()
serv.close()