Gamepad (Joystick) support for myMPD

[antonionardella]

Hey everyone,

I'd like to share that I've gotten myMPD up and running on my Raspberry Pi 3!
I already installed myGPIOd and can skip songs with a button, which made me curious about more possibilities

Now, the ambitious part: I want to use this controller to control myMPD! ️

I managed to connect my trusty NES controller as a joystick (/dev/input/js0) using the Pi 3's GPIO ports (similar to how it is explained here), and it works perfectly in Linux.

This is what jstest shows:

Driver version: 2.1.0
Joystick (NES pad) 2 axes (X, Y)
and 4 buttons (BtnA, BtnB, BtnSelect, BtnStart)

I'm envisioning something like this:

Right on the D-pad goes to the next song, left goes to the previous.
Start button plays/pauses music.
Up on the D-pad raises the volume, down lowers it.

But I'm not quite sure how to make this magic happen.

So, my question to the myMPD community:

How can I integrate my NES controller with myMPD to achieve this sweet, music-controlling dream? Any suggestions, tools, or guides would be greatly appreciated!

Thanks in advance!

P.S. If anyone else has tried something similar with myMPD and controllers, please share your wisdom!

[jcorporation]

You can use curl to call the myMPD api endpoints or use the mpc command line tool. I think you need a script or program that can act with the /dev/input/js0 device. I do not know any.

P.S. Nice project!

[antonionardella]

Alright, DONE!

Using Python and the API

More information here:

https://hackmd.io/@tPxwddC0R3uDaZSGNlIInA/Hy4gZLSoT

Thanks a lot for this awesome tool, support and experience!

Here the code for reference

from evdev import InputDevice, categorize, ecodes
import subprocess
import json

# Define the base URL of the myMPD API
API_URL = "https://localhost:1333/api/default"

# Function to call the myMPD API
def call_mympd_api(method, params=None):
    json_data = {
        "jsonrpc": "2.0",
        "id": 0,
        "method": method,
        "params": params
    }
    
    # Convert JSON data to string
    data_str = json.dumps(json_data)
    
    # Use curl command with data string
    curl_command = f'curl -k -X POST {API_URL} --data \'{data_str}\''

    # Run the curl command and capture the output
    try:
        output = subprocess.check_output(curl_command, shell=True, text=True)
        # Parse the JSON output
        return json.loads(output)
    except subprocess.CalledProcessError as e:
        print(f"Error executing curl command: {e}")
        return None
    except json.JSONDecodeError as e:
        print(f"Error decoding JSON: {e}")
        return None

# Function to handle joystick events
def handle_joystick_event(event):
    print(f"Joystick event: {event}")
    if event == 'BTN_A':
        call_mympd_api('MYMPD_API_DATABASE_RESCAN', {"uri": ""})
    elif event == 'BTN_B':
        call_mympd_api('MYMPD_API_JUKEBOX_RESTART')
    elif event == 'BTN_START':
        # Check player state
        player_state = get_player_state()
        if player_state == 'play':
            call_mympd_api('MYMPD_API_PLAYER_PAUSE')
        elif player_state == 'pause':
            call_mympd_api('MYMPD_API_PLAYER_RESUME')
        else:
            print("Unknown player state")
    elif event == 'BTN_SELECT':
        call_mympd_api('MYMPD_API_PLAYER_LIKE')
    elif event == 'BTN_UP':
        call_mympd_api('MYMPD_API_PLAYER_VOLUME_CHANGE', {"volume": 5})
    elif event == 'BTN_DOWN':
        call_mympd_api('MYMPD_API_PLAYER_VOLUME_CHANGE', {"volume": -5})
    elif event == 'BTN_LEFT':
        call_mympd_api('MYMPD_API_PLAYER_PREV')
    elif event == 'BTN_RIGHT':
        call_mympd_api('MYMPD_API_PLAYER_NEXT')
    else:
        print(f"Unknown event: {event}")

# Function to read joystick events
def read_joystick_events():
    dev = InputDevice('/dev/input/event4')
    print("Listening to joystick events...")
    for event in dev.read_loop():
        if event.type == ecodes.EV_KEY:
            event_value = categorize(event)
            if event_value.keystate == 1:  # Button press event
                if event_value.keycode[0] == 'BTN_A':
                    handle_joystick_event('BTN_A')
                elif event_value.keycode[0] == 'BTN_B':
                    handle_joystick_event('BTN_B')
                elif event_value.keycode == 'BTN_START':
                    handle_joystick_event('BTN_START')
                elif event_value.keycode == 'BTN_SELECT':
                    handle_joystick_event('BTN_SELECT')

        else:
            # Extract code and value directly from the InputEvent object
            code = event.code
            value = event.value

            # Check if the code corresponds to the UP button (code "01") and value indicates a button press ("-1")
            if code == 1 and value == -1:
                handle_joystick_event('BTN_UP')
            elif code == 1 and value == 1:
                handle_joystick_event('BTN_DOWN')
            elif code == 0 and value == -1:
                handle_joystick_event('BTN_LEFT')
            elif code == 0 and value == 1:
                handle_joystick_event('BTN_RIGHT')

# Function to get player state
def get_player_state():
    # Call MYMPD_API_PLAYER_STATE
    result = call_mympd_api('MYMPD_API_PLAYER_STATE')
    if result and 'result' in result and 'state' in result['result']:
        return result['result']['state']
    else:
        print("Failed to get player state")
        return None


# Main function
def main():
    read_joystick_events()

if __name__ == "__main__":
    main()

[antonionardella]

Had a lot of fun building this personal project!

Leaving my notes here for others to follow:

https://hackmd.io/@tPxwddC0R3uDaZSGNlIInA/Hy4gZLSoT

All the best and thanks a lot for all the hours you put in myMPD @jcorporation