Tag Archives: node

Install Node.js 18 on AlmaLinux 8

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List available Node.js versions available.

dnf module list nodejs
AlmaLinux 8 - AppStream
Name           Stream           Profiles                                     Summary
nodejs         10 [d][x]        common [d], development, minimal, s2i        Javascript runtime
nodejs         12 [x]           common [d], development, minimal, s2i        Javascript runtime
nodejs         14 [x]           common [d], development, minimal, s2i        Javascript runtime
nodejs         16 [x]           common [d], development, minimal, s2i        Javascript runtime
nodejs         18 [x]           common [d], development, minimal, s2i        Javascript runtime
nodejs         20 [x]           common [d], development, minimal, s2i        Javascript runtime

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled

As we can see above, nodejs 18 is disabled. Enable it with

sudo dnf module enable nodejs:18

Now we can install with

sudo dnf install nodejs

You may need to uninstall older versions.

How to Display Pictures on NodeJS http Server

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If you are using http for a NodeJS application, you may have run into an issue where none of your images are loading on a site. Instead you are greeted with nice little “no image” logos.

The issue is that our NodeJS server has not been instructed to load anything other than index.html. So other things like images, or even CSS from our style.css file wont work properly.

To fix the issue, we need to to tell NodeJS what to do when other files are requested. As a side note, the person browsing the site may not be requesting the resources directly, but index.html file requests the css file or images hence creating a new web request.

Let’s say we are starting with the following code as a starting point.

var http = require('http')
var fs = require('fs')
var path = require('path')
var url = require('url')

http
  .createServer(function (req, res) {
    let pathname = url.parse(req.url).pathname
    if (
      req.method === 'GET' &&
      (pathname === '/' || pathname === '/index.html')
    ) {
      res.setHeader('Content-Type', 'text/html')
      fs.createReadStream('./index.html').pipe(res)
      return
    }
    return res.end()
  })
  .listen(3000)

Our HTML code is very basic.

<html>
<head>Hello World!</head>
<br />
<body><img src="./image.png" width="128"></body>
</html>

When we launch our server with 

$ node server.js

We get

The Fix

Essentially what we need to do is tell the server what to do when image.png is requested.

So we can add the following to our server code before the line “return res.end()”

    if (req.method === 'GET' && pathname === '/image.png') {
      res.setHeader('Content-Type', 'image/png')
      fs.createReadStream('./image.png').pipe(res)
      return
    }

And voila! it is fixed!

Taking it Further

We can improve on this and add a favicon, as well as our style sheet.

var http = require('http')
var fs = require('fs')
var path = require('path')
var url = require('url')

http
  .createServer(function (req, res) {
    let pathname = url.parse(req.url).pathname
    if (
      req.method === 'GET' &&
      (pathname === '/' || pathname === '/index.html')
    ) {
      res.setHeader('Content-Type', 'text/html')
      fs.createReadStream('./index.html').pipe(res)
      return
    }
    if (req.method === 'GET' && pathname === '/image.png') {
      res.setHeader('Content-Type', 'image/png')
      fs.createReadStream('./image.png').pipe(res)
      return
    }

    if (req.method === 'GET' && pathname === '/favicon.ico') {
      res.setHeader('Content-Type', 'image/x-icon')
      fs.createReadStream('./favicon.ico').pipe(res)
      return
    }

    if (req.method === 'GET' && pathname === '/style.css') {
      res.setHeader('Content-Type', 'text/css')
      fs.createReadStream('./style.css').pipe(res)
      return
    }
    return res.end()
  })
  .listen(3000)

This will let us put a favicon.ico image to use as a favicon it will use style.css to stylize the website.

We should note that while the above code does work, you will most likely want to use something like express.
https://github.com/expressjs/express

You can also find better code implementations others of done online.

https://stackoverflow.com/questions/5823722/how-to-serve-an-image-using-nodejs

Running Node App as systemd Service

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In this post we will be using systemd to run a node application. This is helpful as it will automatically start the app when the server starts so we don’t have to manually. These steps can easily be modified to run a bash script, or any other application.

  • Create systemd file
  • Customize systemd file
  • Enable systemd file

We’ll be creating a service for the Simple Whisper Web Interface as an example. Chang things as needed.

Create systemd file

This is super simple. We create a .service file in /lib/systemd/system. When we enable the service, it will create a symlink to this file.

sudo vim /lib/systemd/system/whisperweb.service

Customize systemd file

Change the settings as appropriate. It would be a good idea to run any service as a limited user that only has the rights needed to get the job done. Do note that you will need to have any prerequisites installed and available for that user to use. I.e. libraries installed with npm etc. 

[Unit]
Description=Simple Whisper Web Interface Service File
After=network.target

[Service]
Type=simple
User=whisperuser
ExecStart=/usr/bin/node mainssl.js
WorkingDirectory=/home/whisperuser/
Restart=on-failure

[Install]
WantedBy=multi-user.target

Enable systemd file

Enabling the service will create a symlink that will then run this service file on system boot.

sudo systemctl enable whisperweb.service

And now we can start the service.

sudo systemctl start whisperweb.service

We can verify that the service is running by running

sudo systemctl status whisperweb.service

The following article has some great explanations on what different options in the unit file mean and do.

https://nodesource.com/blog/running-your-node-js-app-with-systemd-part-1/

Voxer Bot Attempts

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The following are various notes and findings on trying to create a “Bot” for Voxer. Voxer doesn’t really have any options for web hooks, and the SDK is still in beta. We’ll be exploring sending messages to a channel, how to use Curl or Fetch to send messages. Unfortunately, signing in does not appear to be easy to automate.

Looking at Voxer

Voxer is primarily used via the modile apps, but there is also a web version at web.voxer.com

Using Firefox, we can play with the Web Tools to get a better idea of what is going on.

All the Javascript is easily readable. api.js is of interest. This can helps us understand how messages are sent.

The Web interface seems to be somewhat buggy, could be it just doesn’t like going through burp, but had better luck monitoring the channel for new messages from a phone.

Proxying the traffic through Burp is tricky. The log in does not appear to work while the proxy is active, but you can log in, and then activate the proxy to capture and replay sending messages.

If you get “Voxer is open in another tab. Please click ‘OK’ then close this tab.” clear all voxer cookies and log in again. Seems to happen quite often.

Interestingly, if you send a message, then send that message POST request to Repeater, change the text and resubmit it, it “Updates” the text of the message. So if you know the message_id, or maybe the create_time, you can change the text in messages.

About Sending Messages

When you send a message, there are 2 POST requests sent. The first one sends the message and the second one consumes the message. It looks like you really only need the first post message request to actually send messages. Think the consume message post is for the browser to trigger a refresh on the messages in the message list.

There are two variables that change message to message

message_id and create_time

Looking into the api.js file we see that create_time is done with the following code

now = new Date().getTime() / 1000,

And here is the code used to generate the message_id. First part is the time, the next part is random.

window.generate_message_id = function (type) {
        var message_id = new Date().getTime() + "_" + Math.floor((Math.random() * 10000000000) + 1000);

        if (type && type === "image") {
            message_id += "_v1.jpg";
        }

        return message_id;
    };

Structure of the POST request

The following entries are slightly abbreviated

Cookies

There are a bunch of tracking cookies, the session cookie is the one we are interested in. The Rv_session_key is what will allow us to actually send messages. As a side note, it appears that every time we send a message, there is analytics that is also sent, saying who the message was sent to, and when.

session={"gcp1-prod":{"user_id":"MyVoxerUser_ID","Rv_session_key":"db0bc8a069148140151a38bab2098a01"}}

Body

{"message_id":"1681191108600_7318671093","create_time":1681191108,"model":"User_Agent","content_type":"text","from":"MyVoxerUser_ID","subject":"Walkie","body":"This is the text of the message","thread_id":"This.is.the.thread_id"}

Using JavaScript / fetch

After some trial an error, the following solution finally worked. You can copy the following code, and run with “node file.js”

// Change variables as needed
let body = "Hello World!"
// let body = process.argv.slice(2) // You can use this if you want to pass in the message as an argumant. i.e. node voxer.js "Voxer Message"
const threadID = 'ThreadID'
const fromID = 'UserID'
let cookie = `session={"gcp1-prod":{"user_id":"${fromID}","Rv_session_key":"RVSESSIONID"}}`
let time = new Date().getTime() / 1000
let messageID = new Date().getTime() + '_' + Math.floor(Math.random() * 10000000000 + 1000)

// Send message.
function sendMessage () {
  fetch(`https://gcp1-prod-nr60.voxer.com/2/cs/post_message?now=${time}`, {
    credentials: 'include',
    credentials: 'same-origin',
    headers: {
      'User-Agent': 'UserAgent',
      Accept: '*/*',
      'Accept-Language': 'en-US,en;q=0.5',
      'Content-Type': 'text/plain',
      'Sec-Fetch-Dest': 'empty',
      'Sec-Fetch-Mode': 'cors',
      'Sec-Fetch-Site': 'same-site',
      'sec-ch-ua-platform': '"Windows"',
      'sec-ch-ua': '"Opera";v="97", "Chromium";v="97", "Not=A?Brand";v="24"',
      'sec-ch-ua-mobile': '?0',
      Cookie: cookie
    },
    referrer: 'https://web.voxer.com/',
    body: `{\"message_id\":\"${messageID}\",\"create_time\":${time},\"model\":\"\",\"content_type\":\"text\",\"from\":\"${fromID}\",\"subject\":\"CHANGING\",\"body\":\"${body}\\n\",\"thread_id\":\"${threadID}\"}\r\n`,
    method: 'POST',
    mode: 'cors'
  })}

 sendMessage()

You can find the thread_id, user_id, session cookie by toggling the developer console, logging into Voxer, and send a message.

A Very Basic Simple Whisper Web Interface

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Created a little web interface to use Whisper, technically using whisper-ctranslate2 which is built on faster-whisper.

This is not currently ready to be run on the public web. It doesn’t have any sort of TLS for encrypting communications from client to server and all the files are stored on server. Only use in a trusted environment.

Setting up Prerequisite

Installing whisper-ctranslate2

pip install -U whisper-ctranslate2

Install NodeJS

sudo apt install nodejs

or 

sudo dnf install nodejs

Install Node Dependencies

npm install formidable
npm install http
npm install fs

Setting up Simple Whisper Web Interface

First we need a web directory to use.

Next lets make an uploads folder

mkdir uploads

Now let’s create a main.js file. Node is going to be our webserver. Copy the following contents.

var http = require('http')
var formidable = require('formidable')
var fs = require('fs')

const execSync = require('child_process').execSync

let newpath = ''
let modelSize = 'medium.en'
const { exec } = require('node:child_process')
const validModels = [
  'medium.en',
  'tiny',
  'tiny.en',
  'base',
  'base.en',
  'small',
  'small.en',
  'medium',
  'medium.en',
  'large-v1',
  'large-v2'
]
fs.readFile('./index.html', function (err, html) {
  if (err) throw err

  http
    .createServer(function (req, res) {
      if (req.url == '/fileupload') {
        res.write(html)
        var form = new formidable.IncomingForm()
        form.parse(req, function (err, fields, files) {
          console.log('Fields ' + fields.modeltousema)
          console.log('File ' + files.filetoupload)
          var oldpath = files.filetoupload.filepath
          newpath = './uploads/' + files.filetoupload.originalFilename
          modelSize = validModels.includes(fields.modeltouse)
            ? fields.modeltouse
            : 'medium.en'
          console.log('modelSize::' + modelSize)
          fs.rename(oldpath, newpath, function (err) {
            if (err) {
              console.log('No file selected!') // throw err
              res.write(`<div class="results">No file selected</div>`)
            } else {
              console.log(newpath)
              const output = execSync(
                `whisper-ctranslate2 ${newpath} --model ${modelSize}`,
                { encoding: 'utf-8' }
              )

              res.write(
                `<div class="results"><h2>Results:</h2> <p>${output}</p></div>`
              )
              res.end()
            }
          })
        })
      } else {
        res.writeHead(200, { 'Content-Type': 'text/html' })
        res.write(html)
        return res.end()
      }
    })
    .listen(8080)
})

Now create an index.html file and paste the following in

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Voice Transcribing Using Whisper</title>
    <link type="text/css" rel="stylesheet" href="style.css" />
  </head>
  <style>
    body {
      background-color: #b9dbe7;
      align-items: center;
    }

    .box {
      border-radius: 25px;
      padding: 25px;
      width: 80%;
      background-color: azure;
      margin: auto;
      border-bottom: 25px;
      margin-bottom: 25px;
    }

    .button {
      border-radius: 25px;
      margin: auto;
      width: 50%;
      height: 50px;
      display: flex;
      justify-content: center;
      border-style: solid;

      background-color: #e8d2ba;
    }

    h1 {
      text-align: center;
      padding: 0%;
      margin: 0%;
    }

    p {
      font-size: larger;
    }
    .headings {
      font-size: large;
      font-weight: bold;
    }
    input {
      font-size: medium;
    }
    select {
      font-size: medium;
    }
    .results {
      white-space: pre-wrap;
      border-radius: 25px;
      padding: 25px;
      width: 80%;
      align-self: center;
      background-color: azure;
      margin: auto;
    }
    .note {
      font-style: italic;
      font-size: small;
      font-weight: normal;
    }
  </style>
  <body>
    <script></script>
    <div class="box">
      <h1>Simple Whisper Web Interface</h1>
      <br />
      <p>
        Welcome to the very Simple Whisper Web Interface!<br /><br />
        This is a very basic, easy to use, web interface for OpenAI's Whisper
        tool. It has not been extensively tested, so you may encounter bugs or
        other problems.
        <br /><br />
        Instructions for use. <br />1. Select audio file <br />2. Select the
        Model you want to use <br />
        3. Click Transcribe! <br />4. Copy your transcription
      </p>
      <br />
      <br />
      <div class="headings">
        <form action="fileupload" method="post" enctype="multipart/form-data">
          Audio File: <input type="file" name="filetoupload" /><br />

          <br />
          Model:
          <select name="modeltouse" id="modeltouse">
            <option value="medium.en">medium.en</option>
            <option value="tiny">tiny</option>
            <option value="tiny.en">tiny.en</option>
            <option value="base">base</option>
            <option value="base.en">base.en</option>
            <option value="small">small</option>
            <option value="small.en">small.en</option>
            <option value="medium">medium</option>
            <option value="medium.en">medium.en</option>
            <option value="large-v1">large-v1</option>
            <option value="large-v2">large-v2</option>
          </select>
          <p class="note">
            Large-v2 and medium.en seem to produce the most accurate results.
          </p>
          <br />
          <br />
          <br />
          <input class="button" type="submit" value="Transcribe!" />
        </form>
      </div>
    </div>
  </body>
</html>

Now we should be set to go.

Fire the web server up with

node ./main.js

If we want to start it in the background, run

node ./main.js &

Known Limitations or Bugs

If you hit Transcribe with no file selected, the server crashes.

We are calling whisper-ctranslate2 directly, if it is not in the path, then it won’t work.

We are currently using the medium.en model, if the model is not downloaded, then the first transcription may take awhile while it downloads. Would like to add a menu for selecting which model to use. We fixed this by adding a drop down that let’s you select a model.

Would be nice to have an option for getting rid of the timestamps.

Send an Email with Node.JS

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In this post, we will be using Node.JS and the nodemailer library to send email. We need to have an email account with an email provider to send email. Gmail or some other email provider should work.

Prerequisites

First lets install some tools

sudo apt install nodejs npm

Now lets install nodemailer

npm install nodemailer

Writing the Code to Send Email

Now that we have nodemailer installed, we can write or copy our code. Create a file called maill.js and make it look similar to the following.

// We can pass in the email text as an argument
const emailText = process.argv.slice(2);
// Or we can just have it as a variable
// const emailText = "NodeJS test email message."
console.log("args " + args)

const nodemailer = require("nodemailer");

const transporter = nodemailer.createTransport({
  host: "mail.emailserver.com",
  port: 465,    //  If your email server does not support TLS, change to 587
  secure: true, // If you are using port 587, change to false.  Upgrade later with STARTTLS
  auth: {
    user: "smtpuser@emailserver.com",
    pass: "notpassword)",
  },
});

const mailOptions = {
  from: 'user@emailserver.com',
  to: "touser@email.com",
  subject: 'Test Email using NodeJS',
  text: `${emailText}`
};

transporter.sendMail(mailOptions, function(error, info){
  if (error) {
    console.log(error);
  } else {
    console.log('Email sent: ' + info.response);
  }
});

Update the following variables

  • host: to your host email server
  • user: to the email user that is sending email. It should have an account on the email server
  • pass: password for your email user that is sending the email
  • from: email address that is sending the email
  • to: email account(s) you are sending email to
  • subject: subject of your email

Now we can proceed to send email

Sending Email

We can now run the code by saving our file and running it directly with NodeJS

nodejs ./mail.js "This is the body text for the email"

Hit Return and look for the email. If something went wrong, it should throw an error.

You can change the emailText variable if you would rather have the message body inside the code.

Code Explanation and Notes

A little explanation on the code.

The second line “const emailText = process.argv.slice(2);” is used to pass in a command line argument to use as the text for the body of the email. You can delete the line and uncomment line 4 if you would rather use a variable inside the code.

Your email server should support using SSL/TLS on port 465. If it does not, you may need to use STARTTLS which uses port 587, and then set secure to false. STARTTLS should upgrade the connection to be encrypted. But it’s opportunistic. You can read more about STARTTLS, SSL/TLS here https://mailtrap.io/blog/starttls-ssl-tls/

You can change the “to: ” in the mailOptions object to an array of email addresses to send the email to multiple people at once. 

to: ["email1@email.com", "email2@email.com", "etc"],