If I execute a certain shell command in node js, the output is on the console. Is there a way I can save it in a variable so it can be POST to Sqlite database.
const shell = require('shelljs');
shell.exec('arp -a');
In this scenario, I want to store the IP address of a specific MAC/Physical address into the database. How can this be done?
Any help would be much appreciated. Thank you
You need to get the output of the command you're passing to exec. To do that, just call stdout, like this:
const shell = require('shelljs');
const stdout = shell.exec('arp -a').stdout;
Then just parse that output to get your ipaddress:
const entries = stdout.split('\r\n');
// entries sample
[ '',
'Interface: 10.17.60.53 --- 0xd',
' Internet Address Physical Address Type',
' 10.11.10.52 6c-4b-90-1d-97-b8 dynamic ',
' 10.10.11.254 xx-yy-53-2e-98-44 dynamic ']
Then you can filter your wanted address with some more manipulation.
EDIT:
To get the ip address, you could do:
let ipAddr = null;
for (let i = 0; i < entries.length; i++) {
if (entries[i].indexOf('6c-4b-90-1d-97-b8') > -1) {
ipAddr = entries[i].match(/\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/)[0];
break;
}
}
console.log(ipAddr); // '10.11.10.52'
I'm merely copy pasting from the docs. You should research more.
You need to add a listener to stdout
var child = exec('arp -a', {async:true});
child.stdout.on('data', function(data) {
/* ... do something with data ... */
});
Or adding the callback directly when calling exec
exec('some_long_running_process', function(code, stdout, stderr) {
console.log('Exit code:', code);
console.log('Program output:', stdout);
console.log('Program stderr:', stderr);
});
You can access the result of the command run using shell.exec with the .output property. Try the code below.
var shell = require('shelljs');
var result = shell.exec('arp -a').output;
If you don't want the result in the console, you can specify the silent option.
var result = shell.exec('arp -a', {silent: true}).output;
Now, you can use regular expressions to extract ip and mac address from the result.
I am getting the result of the command like below:
? (xxx.xxx.xxx.xxx) at xx:xx:xx:xx:xx:xx [ether] on eth0
? (yyy.yyy.yyy.yyy) at yy:yy:yy:yy:yy:yy [ether] on eth0
You can use the following code to extract ip and mac.
var res = result.split("\n").map(function(item){
return item.match(/\((\d+\.\d+\.\d+\.\d+)\) at (..:..:..:..:..:..)/);
});
console.log(res[0][1]); //IP of first interface
console.log(res[0][2]); //MAC of first interface
console.log(res[1][1]); //IP of second interface
console.log(res[1][2]); //MAC of second interface
NOTE
I was not able to find the .output property in the documentation but trying the shell.exec function in the node console revealed it.
The .stdout property or the exec function mentioned in other answers doesn't work for me. They are giving undefined errors.
Related
For a project I need to incorporate a backend Python function with Javascript (main code for a chatbot). Using Child processes, it seems to work (when using 'node script.js'). However, I need to access the data from the called python function. Right now, all I am getting is the the output.I tried to store it in the global variable, but it's showing as 'undefined'. Is there a way to actually access the data so I can use it outside the stdout.on?
This is the Javascript code for running the pythonscript:
// Give a path to the QR scanner Python file
const qrScannerPath = "python/qrCodeScanner.py"
const base64Arg = "base64_2.txt"
// Provide the '.exe' python file. If python is available as an 'environment varaible', then simply refer to it as 'python'"
const pythonExe = "python"
// Function to convert a utf-8 array to a string
const utfConverter = function (data) {
return String.fromCharCode.apply(String,(data))
}
// let's us handle python scripts
const spawn = require("child_process").spawn
const scriptExe = spawn(pythonExe, [qrScannerPath, base64Arg])
// If all goes well, the program should execute the Python code
let counterpartyData = {}
scriptExe.stdout.on("data", function (data) {
console.log("getting the Python script data...")
let cp = JSON.parse(utfConverter(data))
counterpartyData = {... cp} //should store the data to the variable
});
console.log(counterpartyData) // shows 'undefinied"
// In case our python script cannot be run, we'll get an error
scriptExe.stderr.on("data", (data) => {
console.error("error : " + data.toString())
});
//logs error message
scriptExe.on('error', (error) => {
console.error('error: ', error.message);
});
// Logs a message saying that our code worked perfectly fine
scriptExe.on("exit", (code) => {
console.log("Process quit with code : " + code)
})
If I run this code with node, the output of 'counterpartyData' is undefined. However, inside the stdout, it actually prints out the data I want.
Furthermore, I get python import errors when running the app on Heroku :(.
Thank you in advance!!
Happy New Year and joyful greetings <3
I have a file structure, which I will enumerate for you in a moment. I have a web server, that initiates a command line process on a button press. I want to add in the option to run the server in a headless manner, using a command line argument. Is this the way I should be doing this? Here is my Project Structure.
/models
/model1
/model2
/model3
/routes
/index
/test
/users
/credentials
/adduser
/views
/same as routes. Route 'test' has no layout.
in index, or '/', I have a function, which takes several parameters, and is initiated via clicking a button on the index page. We are then forwarded through 'test/run', and render the 'index' view. The process continues to run in the terminal. I will now post an example of the function.
router.post('/run', ensureAuthenticated, function(req, res){
return res.redirect('/test/running')
});
// Get Homepage
router.get('/running', ensureAuthenticated, function(req, res){
console.log(res.locals.user);
// console.log(app.locals.user);
const var1 = res.locals.user.username;
const var2 = res.locals.user.username;
const var3 = res.locals.user.username;
const var4= res.locals.user.username;
const deets = {
var5,
var6
};
res.render('index');
dosomething(var1, var2, var3, var4, deets);
setInterval(dosomething, 10 * 1000);
})
});
So what do you guys think? How would I be able to implement the passing of var1-6, through the command line? I would greatly appreciate any help from here.
I am running on Windows right now, but the target server is for Ubuntu systems.
In node.js you can pass CLI arguments using build in process variable
for examples
// test.js
var args = process.argv;
console.log(args[0]); // it will give the node executable path
console.log(args[1]); // it will give current file name
console.log(args[2]); // cli arguments start index
now running the code
$ node test.js hello
/usr/bin/node
/home/blackdaemon/test.js
hello
If you like a pattern like "-arg" "value" try this:
var getArgs = function(){
var arr = {};
var last;
process.argv.forEach((a, idx) => {
if(idx > 1){
if(last){
arr[last] = a;
last = undefined;
}
else if(!last && a.match(/-\w+/))
last = a;
}
})
return arr;
}
The result should be:
$ node index no valid command -ar3 dsds -arg1 323
{ '-ar3': 'dsds', '-arg1': '323' }
I'm trying to use mock-cli to stub process.arv in mocha tests for a cli app. I want to test that a message is console.logged when an incorrect argument ("imit") is passed to process.argv (as defined by commands).
I'm trying to adapt the example from the documentation but i don't think i have set everything up correctly.
it passes when i comment out "stdin: require('../mocks/fakeInputStream'), // Hook up a fake input stream" though i know it's not working correctly
it fails with TypeError: sourceStream.on is not a function when run as described below
Can someone see what I'm missing?
/index.js
var commands = ['init'];
function getGitHeadArgs() {
return process.argv.slice(2, process.argv.length);
}
if (getGitHeadArgs().length) {
if (!commands.includes(getGitHeadArgs()[0])) {
console.log("Silly Githead! That's not a githead command");
}
eval(getGitHeadArgs()[0])();
} else {
console.log("You didn't tell githead to do anything!");
}
/testIndex.js
var assert = require('assert');
var index = require('../index.js');
var mockCli = require("mock-cli");
describe("incorrect argument", function() {
it("imit throws an error if an invalid command is raised", function() {
var argv = ['node', '../index.js', 'imit']; // Fake argv
var stdio = {
stdin: require('../mocks/fakeInputStream'), // Hook up a fake input stream
stdout: process.stdout, // Display the captured output in the main console
stderr: process.stderr // Display the captured error output in the main console
};
var kill = mockCli(argv, stdio, function onProcessComplete(error, result) {
var exitCode = result.code; // Process exit code
var stdout = result.stdout; // UTF-8 string contents of process.stdout
var stderr = result.stderr; // UTF-8 string contents of process.stderr
assert.equal(exitCode, 0);
assert.equal(stdout, "Silly Githead! That's not a githead command\n");
assert.equal(stderr, '');
});
// Execute the CLI task
require('../index.js');
// Kill the task if still running after one second
setTimeout(kill, 1000);
});
Is ../mocks/fakeInputStream a valid path?
Is the object at ../mocks/fakeInputStream a valid instance of ReadableStream?
The source code is avalible at GitHub.
Make sure you meet the requirements for the captureStdin(sourceStream, callback) function.
The module uses that function to capture your fakeInputStream and pipe it into a captureStream.
I have the following code in index.js
var settingsFile = "config.json";
var settings = JSON.parse(require("fs").readFileSync(settingsFile));
const net = require('net');
const robot = require("robotjs");
const fs = require("fs");
var client;
var customKeys = {
"scroll_up":'robot.scrollMouse(50, "up");',
"scroll_down":"robot.scrollMouse(50,'down');"
}
function startCommunication(address,port) {
client = net.connect({port: port,host:address}, () => {
// 'connect' listener
console.log('connected to server!');
//client.write('world!\r\n');
});
client.on('data', (data) => {
console.log(data.toString());
var string = data.toString();
console.log(settings.keys[string.substr(1)]);
if(string.substr(0,1) == "d") {
robot.keyToggle(settings.keys[string.substr(1)],"down");
} else {
robot.keyToggle(settings.keys[string.substr(1)],"up");
}
//client.end();
});
client.on('end', () => {
console.log('disconnected from server');
});
}
startCommunication(settings.address,settings.port);
i also have this code in config.json, aka what is parsed into the settings variable.
{
"port":5555,
"address":"192.168.1.118",
"keys":{
"KEY_A":"a",
"KEY_B":"b",
"KEY_X":"x",
"KEY_Y":"y",
"KEY_L":"y",
"KEY_R":"t",
"KEY_DUP":"up",
"KEY_DDOWN":"down",
"KEY_DLEFT":"left",
"KEY_DRIGHT":"right",
"KEY_START":"z",
"KEY_SELECT":"q"
}
}
What The Problem is is that when i get down to either robotjs.togglekeys statement i get the error
Error: Invalid key code specified.
This means that, as there error clearly states, it is getting an invalid keycode. I am guessing that is is some stupid mistake that I made. data in my testing is equal to "dKEY_DRIGHT". the variable string is equal to that but i need to get rid of the d in order for it to work. when i do the live console i am able to get the data that I need by using the same code but somethig goes wrong when it is being ran in the file. anything helps :)
you may try using node-key-sender to send keys presses to your operational system.
Install it with npm install --save-dev node-key-sender.
And send a key to the keyboard using:
var ks = require('node-key-sender');
ks.sendKey('up');
All the values of you config ('a', 'b', ...) are accepted by the lib. You can send them directly.
Check the documentation page for more information: https://www.npmjs.com/package/node-key-sender.
When working in Python I always have this simple utility function which returns the file name and line number from where the function is called:
from inspect import getframeinfo, stack
def d():
""" d stands for Debug. It returns the file name and line number from where this function is called."""
caller = getframeinfo(stack()[1][0])
return "%s:%d -" % (caller.filename, caller.lineno)
So in my code I simply put a couple debug lines like this to see how far we get before some error occurs:
print d()
# Some buggy code here
print d()
# More buggy code here
print d(), 'here is the result of some var: ', someVar
This works really well for me because it really helps debugging quickly.
I'm now looking for the equivalent in a node backend script. I was searching around but I can't find anything useful (maybe I'm looking for the wrong words?).
Does anybody know how I can create a Javascript/nodejs function which outputs the file name and line number from where the function is called? All tips are welcome!
You can create an Error to get where the Error is, and its stack trace. Then you can put that into a function, to get the line where it is.
function thisLine() {
const e = new Error();
const regex = /\((.*):(\d+):(\d+)\)$/
const match = regex.exec(e.stack.split("\n")[2]);
return {
filepath: match[1],
line: match[2],
column: match[3]
};
}
console.log(thisLine());
This works for me in Google Chrome.
And also in node.
Note to #j08691's comment:
Both this and this seem to be using lineNumber, which is not present (as far as I could test) in NodeJS.
Printing line number with custom string
const moment = require('moment');
const log = console.log;
const path = require('path');
function getTime(time) { return moment().format('YYYY-MM-DD HH:mm:ss') };
function line(num = 2) {
const e = new Error();
const regex = /\((.*):(\d+):(\d+)\)$/
const match = regex.exec(e.stack.split("\n")[num]);
const filepath = match[1];
const fileName = path.basename(filepath);
const line = match[2];
const column = match[3];
return {
filepath,
fileName,
line,
column,
str: `${getTime()} - ${fileName}:${line}:${column}`
};
}
log(line().str, "mylog1");
log(line().str, "mylog2");
log(line().str, "mylog3");
OUTPUT
2021-11-22 13:07:15 - test.js:44:5 mylog1
2021-11-22 13:07:15 - test.js:45:5 mylog2
2021-11-22 13:07:15 - test.js:46:5 mylog3
You can use this gulp plugin gulp-log-line . It Logs file and line number without the extra cost of reading the stack.
you just have to install gulp and gulp-log-line using the
npm install gulp --save and npm install gulp-log-line command. after that you need to create and write the below code in gulpfile.js and run
gulp log-line to create a duplicate file in the build folder :-
var gulp = require('gulp');
var logLine = require('gulp-log-line');
gulp.task('line-log', function() {
return gulp.src("file.js", {buffer : true})
//Write here the loggers you use.
.pipe(logLine(['console.log', 'winston.info']))
.pipe(gulp.dest('./build'))
})
gulp.task('default', ['line-log'])
Example
file.js :-
console.log('First log')
var someVariable
console.log('Second log')
Becomes
console.log('file.js:1', 'First log')
var someVariable
console.log('file.js:3', 'Second log')
The only way I've found to get anything relating to line numbers is to trap the window.onerror function, and when there's an error that will get passed the error message, the file URL and the line number:
window.onerror = function(msg, url, line) {
alert(msg + "\n" + url + ":" + line);
};
This works for me on Chrome - I don't know about other browsers.
EDIT when this answer was given in Feb' 15 there was no mention of NodeJS in the question. That was only added in November '17.