In this example, we'll see how to build and use a simple client-server communication using the Pyro4 middleware. The code for the client is pyro_server.py:

1. Import the Pyro4 library:

import Pyro4

2. Define the Server class that contains the welcomeMessage() method that will be exposed:

class Server(object):
    @Pyro4.expose
    def welcomeMessage(self, name):
        return ("Hi welcome " + str (name))

3. The startServer function contains all the instructions that are used to start the server:

def startServer():

4. Next, build the server instance of the Server class:

server = Server()

5. Then, define the Pyro4 daemon: 

daemon = Pyro4.Daemon()

6. To execute this script, we must run a Pyro4 statement to locate a nameserver:

ns = Pyro4.locateNS()

7. Register the object server as Pyro object; it will only be known inside the Pyro daemon:

uri = daemon.register(server)

8. Now, we can register the object server with a name in the nameserver:

ns.register("server", uri)

9. The function ends with a call to the daemon's requestLoop method. This starts the event loop of the server and waits for calls:

print("Ready. Object uri =", uri)
daemon.requestLoop()

10. Finally, call startServer via the main program:

if __name__ == "__main__":
    startServer()

Here is the code for the client (pyro_client.py):

1. Import the Pyro4 library:

import Pyro4

2. The Pyro4 API enables the developer to distribute objects in a transparent way. In this example, the client script sends requests to the server program in order to execute the welcomeMessage() method:

uri = input("What is the Pyro uri of the greeting object? ").strip()
name = input("What is your name? ").strip()

3. Then, the remote call is created: 

server = Pyro4.Proxy("PYRONAME:server")

4. Finally, the client calls the server, printing a message:

print(server.welcomeMessage(name))