Client-Server template

The following is an explananation on how to use the client-server template provided. The template uses sockets (default python lib) to send JSON data between 2 computers. This is taken out of the DDS to ARTIQ link made during the summer 2024.

Successfully used alongside ARTIQ 5 integration.

Server.py

Server.py contains the code to be run on the host machine. It stays on running and waits for data from the client.

Doc

start_server

Starts the server, infinite loop and always listening.

• host='127.0.0.1' : IP to on which the server is running, default to localhost for internal tests
• port=65432 : Port on which the server is running, defaults to 65432, arbitrary, however avoid common ports and make sure it is not already in use.
• debug=False : If sets to True, prints debug messages, check code for more information.

Usage example

if __name__ == "__main__":
    start_server(host="127.0.0.1", port=65432)

interact

Called upon receiving data.

• data : JSON object already parsed.

To get parameters passed in the JSON object use the following : data["parameter_name"]. Additional informations on JSONs can be found in the Official Documentation.

Usage example

def interact(data):
    # Example of what to do with json data :
    if data["command_id"] == "test_command":
        print("Received data is the following : ",data)
        print("Data of param1 : ", data["param1"])
        print("Data of param2 : ", data["param2"])
        print("Data of param3 : ", data["param3"])
        print("Data of param4 : ", data["param4"])

Client.py

Client.py contains the code to be run on the client machine. Connection and deconnection is performed at each data exchange to avoid hanging.

Doc

send_data

Function used to send data to a server.

• json_data : JSON data to send to the server.
• host='127.0.0.1' : IP of the host machine of the server. Defaults to localhost for internal tests
• port=65432 : Port on which the server is running, defaults to 65432, check the server configuration.
• debug=False : If sets to True, prints debug messages, check code for more information.

Additional informations on JSONs can be found in the Official Documentation.

Usage example

if __name__ == "__main__":
   data = {
       "command_id": "test_command",
       "param1": 100,
       "param2": "this is text",
       "param3": True,
       "param4": [1,2,3,4, "text in list"]
   }

   send_data(data, host='127.0.0.1', port=65432,)

server_success

Function called when the server reports operation success.

• response_data : JSON data returned by the server. Add your own code handling success here. No feedback inside the data, you can implement your own.

Usage example

def server_success(response_data):
    print("Server reported success.")

server_fail

Function called when the server reports operation failure.

• response_data : JSON data returned by the server. Add your own code handling failure here. No feedback inside the data, you can implement your own.

Usage example

def server_fail(response_data):
    print('Server reported an error. {}'.format(response_data.get("error")))

fail_connect

Function called when the server client cannot connect/contact the server.

• No parameters

Usage example

def fail_connect():
    print("Failed to connect to the server or the server timed out.")

Real-life application examples

Please check Linking DDS to ARTIQ of E-Lab, which is where this template is extracted from.