node-netstat

A library utility for reading netstat data. It's been tested on Ubuntu 14.04/16.04, Windows 7 and OS X Yosemite.

Installation

node-netstat can be installed via npm:

$ npm install node-netstat

Usage

var netstat = require('node-netstat');

netstat({
	filter: {
		pid: 4123,
		protocol: 'tcp'
	},
	limit: 5
}, function (data) {
    // a single line of data read from netstat
});

API

void netstat(object options, function handler)

Executes a netstat query with any options supplied and executes handler for each line result read from netstat.

The handler signature is void|boolean function(object parsedItem) where parsedItem represents a single result from netstat. A typical parsedItem will look like this:

var item = {
    protocol: String,   // 'tcp', 'udp', or 'tcp6'
    local: {
		port: Number,
		address: String // null if a loopback address
	},
    remote: {
		port: Number,
		address: String // null if a loopback address
	},
    state: '',
    pid: Number         // 0 if it could not be found/parsed
};

If the return value is false, processing will stop and any remaining results will not be parsed.

Options

• sync - (boolean) execute the operation synchronously.
  • Execution is asynchronous by default.
• done - (function(error)) node-style callback, executed after the netstat command completed execution or encountered an error`.
• platform - (string) overrides the platform value returned from os.platform().
• limit - (number) limits the results read and parsed from the netstat process. Nothingness means no limit.
• filter - (object) a hash of value conditions for parsed line objects. If a key/value doesn't correspond with one(s) on a parsed object, handler won't get called.
• watch - (boolean) repeatedly run until processing is cancelled by the line handler or by the external handler.

object netstat.commands

A hash map with command pattern objects:

{
	cmd: 'netstat',
	args: ['-lmnop', '--tcp']
};

The keys in netstat.commands correspond to the standard os.platform() return values ('linux', 'win32').

object netstat.parsers

A hash map of line parse handlers with keys corresponding to os.platform() values.

Line parsers have the following signature:

function (line, callback) {
	// parse line contents
	callback(parsedItem);
}

line is a raw line of output read from netstat. callback is a function and accepts a single argument: the parsed data object.

object netstat.parserFactories

A hash map of the factory functions used to generate the default parsers with keys corresponding to os.platform() values. Some factories include options that may be customized for specific use cases.

Linux

Options

• parseName - (boolean) parse and include processName in results. Default: false

Common Recipes

Include the process name and allow filtering on it (linux only)

const netstat = require('node-netstat');

netstat.parsers.linux = netstat.parserFactories.linux({
  parseName: true,
});

netstat({}, item => console.log(item));

/* output:
{ protocol: 'tcp',
  local: { port: 631, address: '127.0.0.1' },
  remote: { port: NaN, address: null },
  state: 'LISTEN',
  pid: 0,
  processName: '' }
{ protocol: 'tcp',
  local: { port: 1339, address: '127.0.0.1' },
  remote: { port: NaN, address: null },
  state: 'LISTEN',
  pid: 10474,
  processName: 'node' }
*/

object netstat.filters

A hash map of closure factories to handle logic for certain options. See source for more details on implementations for specific filters.

object netstat.utils

An object with several useful functions for implementing custom parsers.

string netstat.version

The version of node-netstat

Canceling async netstat externally

If the watch option is set, the line handler can never be called. To deal with this scenario, a handler is returned and can be called to cancel netstat watching externally.

const impossibleFilter = {...};
let handler = netstat(impossibleFilter, item => console.log(item));

...

// Some time later we need to finish our script,
// we cancel netsat so
handler.cancel();

Any subsequent call to handler.cancel() takes no effect.

Extensions

node-netstat is highly extensible via the filters, parsers, and commands properties.

Bugs and Feedback

If you see a bug or have a suggestion, feel free to open an issue here.

Contributions

PR's welcome! There are no strict style guidelines, just follow best practices and try to keep with the general look & feel of the code present. All submissions must pass jslint and have a test to verify (if applicable).

License

Unlicense. This is a Public Domain work.

"Make art not law" -Nina Paley