About

Monitor Windows process creation/deletion events via WMI (WQL) in Node.js

Example

import { promises as WQL } from 'wql-process-monitor';

const processMonitor = await WQL.subscribe({
  filterWindowsNoise: false
});

processMonitor.on("creation", ([process,pid,filepath]) => {
  console.log(`creation: ${process}::${pid} ["${filepath}"]`);
});

processMonitor.on("deletion",([process,pid]) => {
  console.log(`deletion: ${process}::${pid}`);
});

/*
Keep alive
You don't need this if you have something else to keep the event loop running.
This is just as an example so Node.js doesn't exit directly.
*/
setInterval(()=>{}, 1000 * 60 * 60);

Do something when a specific process is started :

const processMonitor = await WQL.subscribe({
  creation: true,
  deletion: false,
  filter: ["firefox.exe"],
  whitelist: true
});

processMonitor.on("creation", ([process,pid,filepath]) => {
  console.log(`creation: ${process}::${pid} ["${filepath}"]`);
});

Installation

npm install wql-process-monitor

Prerequisite: C/C++ build tools (Visual Studio) and Python 3.x (node-gyp) in order to build node-ffi-napi.

API

Promises are available for all methods under the .promises obj.

//Example cjs
const WQL = require('wql-process-monitor');
WQL.createEventSink(); //sync
WQL.promises.createEventSink(); //promise

💡 Usage of promise instead of sync is recommended so that you will not block Node's event loop.

subscribe([obj option]) : AsyncEventEmitter

⚙️ Options:

• creation | bool (default true)

  Subscribe to the creation event

• deletion | bool (default true)

  Subscribe to the deletionn event

• filterWindowsNoise | bool (default false)

  Exclude events originating from System32 and SysWOW64 Windows folder as well as integrated OneDrive FileCoAuth.exe.
  Ex: cmd.exe, powershell.exe, svchost.exe, RuntimeBroker.exe, and others Windows processes.
  

  ⚠️ NB: Using this will prevent you to catch any elevated process event.
  Unless you are also elevated. This is a permission issue (See #2).
  You can implement your own filter on top of the event emitter result instead.

• filterUsualProgramLocations | bool (default false)

  Exclude events originating from Program Files, Program Files (x86), AppData local and AppData Roaming.

  ⚠️ NB: Using this will prevent you to catch any elevated process event.
  Unless you are also elevated. This is a permission issue (See #2).
  You can implement your own filter on top of the event emitter result instead.

• filter | array of string (default none)

  Custom list of process to exclude.
  eg: ["firefox.exe","chrome.exe",...]
  

  NB: There are limits to the number of AND and OR keywords that can be used in WQL queries. Large numbers of WQL keywords used in a complex query can cause WMI to return the WBEM_E_QUOTA_VIOLATION error code as an HRESULT value. The limit of WQL keywords depends on how complex the query is
  cf: https://docs.microsoft.com/en-us/windows/win32/wmisdk/querying-with-wql
  If you have a huge list consider implementing your own filter on top of the event emitter result instead.

• whitelist | bool (default false)

  Use filter option as a whitelist.
  filterWindowsNoise / filterUsualProgramLocations can still be used.
  Previously mentioned limitation(s) still apply.

✔️ Return a non-blocking async event emitter (emittery):

.on("creation", ([process,pid,filepath]) => {})
.on("deletion", ([process,pid]) => {})

*filepath is only available in "creation" (well it doesn't make sense to open a deleted process for its information ^^) and will sometimes be empty because of permission to access a process information and in the same fashion 32bits can not access 64 bits.

💡 Don't forget to keep the node.js event loop alive.

createEventSink(void) : void

Initialize the event sink.
This is required to do before you can subscribe to any events.
If the event sink is already initialized then nothing will be done.

💡 Since version >= 2.0 this is automatically done for you when you call subscribe().
Method was merely kept for backward compatibility.

⚠️ If your application (the caller thread) is initializing a COM library you need to set the thread model to COINIT_MULTITHREADED For this reason using this in Electron's main process isn't viable. If you really need to use Electron's main process; Here are some workarounds:

• spawn a node child process to execute this module
• use web workers
• use a hidden browser window and communicate between the main process and background window via Electron's IPC.

closeEventSink(void) : void

Properly close the event sink.
There is no 'un-subscribe' thing to do prior to closing the sink. Just close it.
It is recommended to properly close the event sink when you are done if you intend to re-open it later on.
Most of the time you wouldn't have to bother with this but it's here in case you need it.