How to know the port of a message in a callback ? #389
-
|
Hello, I listen to several MIDI controllers with a single callback function (the number of controllers is not fixed). Thank you very much for this very good project! |
Beta Was this translation helpful? Give feedback.
Replies: 4 comments 6 replies
-
|
Callbacks are a per-port setting. Just pass a different function for each port. |
Beta Was this translation helpful? Give feedback.
-
|
Thank you for your answer. I'll keep looking, I'll post my solution when I find it. |
Beta Was this translation helpful? Give feedback.
-
|
If you need a generic solution, one way to go would be to create your own class to encapsulate the midi port and callback. I've done something similar in MIDI Explorer. Something like: import mido
class MyMidiIn():
"""A thin wrapper around mido input port"""
name: str # The port name
port: mido.ports.BaseInput # The port itself
def __init__(self, name: str) -> None:
self.name = name
self.port = mido.open_input(self.name)
self.port.callback = self.receive_callback
def __del__(self) -> None:
self.port.callback = None
self.port.close()
def receive_callback(self, message: mido.Message) -> None:
"""A generic callback"""
# Do your thing here. You have access to self.name and self.port to know which port you are.
###
# Usage
###
my_input = MyMidiIn("the input name") # Opens the port and sets the callbackThere are other methods, this is just the first that came to mind. |
Beta Was this translation helpful? Give feedback.
-
|
Thank you so much ! |
Beta Was this translation helpful? Give feedback.
-
|
I have tried the code above and something similar but its not working for me and I'm not sure where I am going wrong. I am probably not understanding a fundamental concept of how the program flow works with callbacks , classes etc. What I am trying to do? I want to listen to midi input and send it to a callback handler which contains a series of logic statements. What happens? Script runs without error but is exiting immediately rather than as it were staying and doing whatever is defined in note handler eg printing note details to screen Example Script |
Beta Was this translation helpful? Give feedback.
-
|
Ok so after much trial and error this seems to work. The only difference I can see is that you seem to need to have some kind of loop open , although, if u understand correctly this doesn't necessarily have to be a time.sleep, this might be achieved if this script was integrated into a gui application which had a mainloop function?? |
Beta Was this translation helpful? Give feedback.
-
|
Sorry for the late reply. The callback is asynchronously called in another thread so, yes, you need some kind of mainloop in your program to keep it running. In MidiExplorer, I effectively use the GUI’s mainloop. |
Beta Was this translation helpful? Give feedback.
-
|
I think I found a solution by creating callback functions dynamically (thanks to stackoverflow.com). Here is a sample script as proof of concept (interested in your opinions) : import mido
def function_builder(port):
def scan(msg):
print(port, msg)
return scan
inports = list(set(mido.get_input_names()))
scan_functions = {}
for port in inports:
print(port)
inport = mido.open_input(port)
scan_functions[port] = function_builder(port)
inport.callback = scan_functions[port]
while True:
pass |
Beta Was this translation helpful? Give feedback.
-
|
This looks clunky to me. Check my answer above. |
Beta Was this translation helpful? Give feedback.
-
|
@rdoursenaud's code (see #389 (reply in thread)) does the job. Thanks! |
Beta Was this translation helpful? Give feedback.
@rdoursenaud's code (see #389 (reply in thread)) does the job. Thanks!