How to send commands from a BAT file to running NodeJS process in windows?

Question

Is it possible to make/use custom text commands in a batch file while running a nodejs server through it?

//Current batch file
  node nodeServer.js

//nodeServer.js
 function list(){
  //insert query
 }
 function unlist(){
  //delete query
 }

As of now, after i start the batch file, the nodeServer.js is started and the batch stops accepting any input.

I'd like to be able to type "nodeServer.js list"(in the batch window) and with that, call a function called "list" inside nodeServer.js,

I'm looking to insert data about the server into a database by running a insert query with the "list" function and run a delete query with nodeServer.js unlist to remove the inserted row before shutting down the server again.

I'm unfamiliar with batch files, Is this possible?

Update

To Clarify.. I want to type a text command IN the batch window, AFTER it have started the nodejs server, to run a specific function found inside the nodeServer.js

Answer 1

You want to send command to the NodeJS after the node process started.

• To start a command form NodeJS without pause the bat file use start
• To send the command I will use a simple text file. I will write to the file from the batch using echo and read the file form NodeJS using watch, and readFileSync
• I will support sending function name and arguments using spaces. for example: list a b c

The BAT file:

@echo off This is make the bat file to  not show the commands
REM `Rem` do nothing. It is exactly like // in javascript

REM This will start NodeJS without pause the bat
start node myNode.js

REM delete the command file if it exists
del command

REM Send 3 commands to the file. You can also add parameters
echo list >> command
echo list a b c>> command
echo unlist>> command

var fs = require('fs') var filename = __dirname + '/command'

// Add here any command you want to be run by the BAT file
var commands = {
    list: function() {
        console.log('list', arguments)
    },
    unlist: function() {
        console.log('unlist', arguments)
    }
}


console.log('watching:' + filename)
if (fs.existsSync(filename)) {
    console.log('File exists, running initial command')
    runCommand()
}
require('fs').watchFile(filename, runCommand)

function runCommand() {
    if(!fs.existsSync(filename)) return
    var lines = fs.readFileSync(filename, 'utf-8').split('\r\n')
    console.log(lines)
    fs.unlink(filename)
    for(var i=0;i<lines.length;i++){
        var line=lines[i]
        console.log(line)
        line=line.split(' ') // Split to command and arguments
        var command = line[0]
        var args = line.slice(1)
        if (!commands[command]) {
            console.log('Command not found:"' + command +'"')
            return;
        }
        console.log('Running command:', command, '(', args, ')')
        commands[command].call(null, args)
    }
}

Read more about FileSystem node Module: https://nodejs.org/docs/latest/api/fs.html#fs_class_fs_stats