Non Session Manager client library in Python - Version2: No dependencies.
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Non Session Manager client library in Python - Version2: No dependencies except Python3.

PyNSMClient 2.1 - A Non Session Manager Client-Library in one file.

Copyright (c) 2014-2018, Nils Hilbricht, All rights reserved.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public

Short Instructions

You can use as a starting point, or copy to your own program and import and initialize it as early as possible. Then add nsmClient.reactToMessage to your event loop.

from nsmclient import NSMClient
nsmClient = NSMClient(prettyName = niceTitle, #will raise an error and exit if this example is not run from NSM.
    saveCallback = saveCallbackFunction,
    openOrNewCallback = openOrNewCallbackFunction,
    supportsSaveStatus = False,         # Change this to True if your program announces it's save status to NSM
    exitProgramCallback = exitCallbackFunction,
    hideGUICallback = None, #replace with your hiding function. You need to answer in your function with nsmClient.announceGuiVisibility(False)
    showGUICallback = None,  #replace with your showing function. You need to answer in your function with nsmClient.announceGuiVisibility(True)
    loggingLevel = "info", #"info" for development or debugging, "error" for production. default is error.

Don't forget to add nsmClient.reactToMessage to your event loop.

  • Each of the callbacks (save, open/new and exit) receive three parameters: ourPath, sessionName, ourClientNameUnderNSM.
  • openOrNew gets called first. Init your jack client there with ourClientNameUnderNSM as name.
  • exitProgramCallback is the place to gracefully exit your program, including jack-client closing.
  • saveCallback gets called all the time. Use ourPath either as filename or as directory.
    • If you choose filename add an extension.
    • If you choose directory make sure that the filenames inside are static, no matter what project/session. The user must have no influence over file naming
  • Additional callbacks are: hideGUICallback and showGUICallback. These receive no parameters and need to answer with the function: nsmClient.announceGuiVisibility(bool). That means you can decline show or hide, dependending on the state of your program.

The nsmClient object has methods and variables such as:

  • nsmClient.ourClientNameUnderNSM
    • Always use this name for your program
  • nsmClient.announceSaveStatus(False)
    • Announce your save status (dirty = False / clean = True), If your program sends those messages set supportsSaveStatus = True when intializing NSMClient with both hideGUICallback and showGUICallback
  • nsmClient.sessionName
  • nsmClient.announceGuiVisibility(bool)
    • Announce if your GUI is visible (True) or not (False). Only works if you initialized NSMClient with both hideGUICallback and showGUICallback. Don't forget to send it once for your state after starting your program.
  • nsmClient.importResource(filepath)
    • Use this to load external resources, for example a sample file. It links the sample file into the session dir, according to the NSM rules, and returns the path of the linked file.
  • nsmClient.debugResetDataAndExit()
    • Deletes self.ourpath recursively and exists the client. This is only meant for debugging and testing.

Long Instructions

  • Read and start, then read and understand It requires PyQt5 to execute and a brain to read.
  • For your own program read and learn the NSM API:
  • The hard part about session management is not to use this lib or write your own but to make your program comply to the strict rules of session management.

Sources and Influences


  • Convenience for programs that can change the session without restarting.
  • Full NSM API support in general