I know this is security-wise an absolute No-Go. But my customer is going to use a SAPUI5 developed application in the browser within the intranet upon which my preinstalled browser extension will be invoked (using "matches") which should simply collect the PRINTER names on the local workstation and supplies back to the application which is to be used for further processes. I have the below node js code which return the printernames but how to run this in browser engine.
const { exec } = require('child_process');
exec('get-printer | Select-Object Name | ConvertTo-Json', { 'shell': 'powershell.exe' }, (error, stdout, stderr) => {
console.log(stdout);
})
You can't. You will need to expose your nodeJS code as an API which can be called by the browser environment. You could try exposing it as a REST endpoint inside a nodejs express app.
Check this example: https://www.geeksforgeeks.org/how-to-connect-node-js-with-react-js/
Related
There is a server, that I have an access to, but do not have ownership on. It serves a node js / express application on a default port 3000. There are several scripts, that are usually run either manually from the terminal or by cron job. What I want to do is to have a button on the client-side and make an ajax request to a certain route and execute a node js command with inline arguments. For example:
node script.js 123
All routes are set and working. I have a CliController file that handles requests and has to run the command above. Currently I am using the following code:
cp.exec(`node script.js ${ip}`, function (err, stdout, stderr) {
if (err) {
console.log(err);
}
console.log(stdout);
console.log(stderr);
});
The script.js file is in root folder of the project, but the project itself was built by using express-generator and is being served using node bin/www command. There is a service/process on the server that runs nodemon to restart this project if it fails as well. Therefore I do not have access to output of that particular process.
If I run the command above in the terminal (from the root folder of the project, to be precise), it works fine and I see the output of the script. But if I press the button on the webpage to make a request, I am pretty sure that the script does not execute, because it has to make an update to database and I do not see any changes. I also tried to use child_process.spawn and child_process.fork and failed to get it working.
I also tried to kill nodemon and quickly start the project again to the see console output. If I do this, everything works.
What am I doing wrong ?
The process invoked may be in a blocking state, hence the parent script is simply waiting for the children process to terminate, or return something.
We can avoid this behaviour right into the shell command, by adding & (ampersand control operator) at the end.
This makes a command running in the background. (Notice, you can still control the children(s) process using the PID's and POSIX signals, this is another subject, but very related and you might find it very handy pretty soon).
Also notice that killing/stopping the parent script will also kill the children(s). This can be avoided using nohup.
This is not linked to JavaScript or node.js, but to bash, and can be used with anything in the shell.
cp.exec(`node script.js ${ip} &`, function (err, stdout, stderr) {
if (err) {
console.log(err);
}
console.log(stdout);
console.log(stderr);
});
Bash reference manual
I have an Express application that spawns a Python process to execute a Python script. When I do a firebase serve, I can see that my endpoint is being hit, which then runs the Python process. However, the process doesn't seem to be executing.
const runPythonScript = () => {
return new Promise((resolve, reject) => {
let value;
const spawn = require('child_process').spawn;
const pythonProcess = spawn('python', ['./myScript.py']);
pythonProcess.stdout.on('data', (data: string) => {
console.log('Am I being hit?') // This line is not being hit
value = JSON.parse(data);
});
pythonProcess.on('exit', (code: number) => {
if (code === 0) {
resolve(value);
}
else {
reject(value);
}
});
});
}
From the comment in the code above, the listener for stdout 'data' is not being hit. I'm not too familiar with Firebase, but my idea is to use Firebase Hosting for my frontend and then Firebase Cloud Functions to run my Express server. Is there anything that I need to do in order for my application to run the Python script?
From what I've gathered from other StackOverflow posts (here), I can't run a Python process, perhaps because Firebase Cloud Functions does not have Python installed. So instead, I need to package my Python script into an executable (as described here), so that Firebase Cloud Functions can just run the executable. Is this correct? If so, I would prefer not to have to package all of my Python scripts. Is there a better approach to handling this? Is it free?
From what I've gathered from other StackOverflow posts, I can't run a Python process, perhaps because Firebase Cloud Functions does not have Python installed.
This is true.
So instead, I need to package my Python script into an executable (as described here), so that Firebase Cloud Functions can just run the executable. Is this correct?
You can certainly try this, but I don't recommend it. It sounds like a lot of work for little benefit, especially when you have other options.
Is there a better approach to handling this?
You can write Cloud Functions natively in python. You just won't be able to use Firebase tools to test and deploy them. Google Cloud has everything you need to get started.
I am trying to write a file in nodejs and it is working fine using below code:
writeFile() {
const sharedFolderPath = "\\server\folder";
fs.writeFile(sharedFolderPath, templatePath, (err) => {
if (err) {
console.error(err);
} else {
console.info("file created successfully");
}
})
}
It is writing into the shared drive because I have permissions but I want to do it using superuser account but not getting how to inject superuser credentials?
The same above code failed if I am using with different user machine. Is there any way to write a file in NodeJS in shared folder using credentials?
It looks like you are using Windows and writing into a shared folder. The superuser in Windows is LOCAL_SYSTEM but it only has superuser privileges on a local machine (otherwise a compromised LOCAL_SYSTEM could wreck havoc in your network). In other words, running an application as Administrator would not grant it privileges to bypass shared folder permissions.
The easiest solution would be to make that shared directory writable by the users you intend to run this application under.
I'm learning nodejs and I want to send some file to the printing queue.
I tried elctron-printer and node-printer modules but actually they do not work proprly (can't detect printer with printer.list command for example). Now I'm trying to make it with child_process module and I want to know is there any posibility to start file with its associated application with "print" argument like a python can do it?
For example, this is a code sample of file execution with nodejs:
var childProcess = require('child_process');
childProcess.exec('start printme.txt', function (err, stdout, stderr) {
if (err) {
console.error(err);
return;
}
console.log(stdout);
process.exit(0);// exit process once it is opened
})
Unfortunately it seems that "print" argument is invalid for this code.
And this is a code sample for python and it works fine on windows:
import os
os.startfile('printme.txt', 'print')
All in all I hope that there is possibility to emulate system commands with nodejs.
Otherwise I will have to execute python script via nodejs just for file printing, something like this:
let python = spawn('python', [path.join(app.getAppPath(), '..', 'python_scripts/print_file.py'])
But it is terrible way to do it.
I know Windows 8 'apps' can be developed using web technologies but I haven't been able to find out if terminal commands can be run in the background using web technologies as an interface. I basically have mongoDB on my computer and it takes two terminal windows open to run it. I thought it might be a neat project to see if I could write a little app that is nothing more than a button that launches both commands behind the scenes saving me the hassle of going to the directories and running the commands manually for both terminal windows.
If you plan to launch apps via server-side JavaScript (e.g. node.js), use the child_process module..
The workflow would be that in the windows 8 gui side, it will just issue a request to your own local server in node.js, then it would execute those commands.
Example:
var exec = require('child_process').exec;
var child = exec("insert command here", function(err, stdout, stderr) { });
See examples exec and spawn for more examples.
======
Another thing you can do is create a batch (.bat) file that contains those two commands needed for your mongodb instance and put that as a shortcut in the Windows 8 Start Screen.
It depends on what kinds of commands you need to execute, and when and where. If you plan to execute commands remotely, I'd assume server-side JS would be appropriate, but if you plan to execute commands locally, I think all you need is just batch scripting.