When i want to read a file in node js it won’t display the file in the browser when I execute. and in the terminal says no such file or directory while I use the exact file path anyone can answer this why?
How to do sos using terminal?
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const fs = require('fs');
const events = require('events');
const bf =require('buffer');
const REQUIRED_LINES = 10;
function createWatcher(logFile) {
const queue = [];
const eventEmitter = new events.EventEmitter();
const buffer = Buffer.alloc(bf.constants.MAX_STRING_LENGTH);
function readfile(curr, prev) {
// Create a read stream from the file
const readStream = fs.createReadStream(logFile, {
start: prev.size,
encoding: 'utf8'
});
let data = '';
readStream.on('data', chunk => {
data += chunk;
});
readStream.on('end', () => {
let logs = data.split('n').slice(1);
console.log("logs read: " + logs);
if (logs.length >= REQUIRED_LINES) {
logs.slice(-REQUIRED_LINES).forEach(elem => queue.push(elem));
} else {
logs.forEach(elem => {
if (queue.length === REQUIRED_LINES) {
console.log("queue is full");
queue.shift();
}
queue.push(elem);
});
}
eventEmitter.emit("process", logs);
});
readStream.on('error', err => {
console.error("Error reading the file:", err);
});
}
// Define the start function
function startpoint() {
fs.open(logFile, 'r', (err, fd) => {
if (err) throw err;
let data = '';
let logs = [];
fs.read(fd, buffer, 0, buffer.length, 0, (err, readbytes) => {
if (err) throw err;
if (readbytes > 0) {
data = buffer.slice(0, readbytes).toString();
logs = data.split("n");
queue.length = 0; // Clear the queue
logs.slice(-REQUIRED_LINES).forEach((elem) => queue.push(elem));
}
fs.close(fd, (err) => {
if (err) throw err;
});
});
fs.watchFile(logFile, { interval: 1000 }, (curr, prev) => {
readfile(curr, prev);
});
});
}
return {
getLogs: function() {
return queue;
},
emit: function(eventName, ...args) {
eventEmitter.emit(eventName, ...args);
},
on: function(eventName, listener) {
eventEmitter.on(eventName, listener);
},
off: function(eventName, listener) {
eventEmitter.off(eventName, listener);
},
start: startpoint
};
}
module.exports = createWatcher;
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const fs = require('fs');
const path = 'test.log';
let lineNumber = 1; // Initialize line number
const getRandomInt = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
// Function to generate a random string of characters
const generateRandomString = (length) => {
const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
let result = '';
for (let i = 0; i < length; i++) {
result += characters.charAt(getRandomInt(0, characters.length - 1));
}
return result;
};
// Function to write a new line to the file
const writeToFile = () => {
const randomString = generateRandomString(8); // Generate an 8-character long random string
const content = `Line ${lineNumber}: ${randomString}`;
// Append a newline before the new content to ensure it starts on a new line
fs.appendFile(path, `n${content}`, 'utf8', (err) => {
if (err) {
console.error('Error appending to file:', err);
return;
}
console.log(`Content successfully appended: ${content}`);
// Increment line number
lineNumber++;
});
};
// Interval in milliseconds (e.g., 2000 ms = 2 seconds)
const interval = 1000;
// Run the write function continuously
setInterval(writeToFile, interval);
<!DOCTYPE html>
<html>
<head><title>Tail -f</title></head>
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io("ws://localhost:3000");
socket.on('update-log', function(data){
console.log(data);
for(elem of data) document.getElementById('message-container').innerHTML +='<p>' + elem + '</br><p>';
});
socket.on('init',function(data){
console.log(data);
for(elem of data) document.getElementById('message-container').innerHTML +='<p>' + elem + '</br><p>'; })
</script>
<body>
<h1>Log monitoring app</h1>
<div id="message-container"></div>
</body>
</html>const express = require('express');
const app = express();
const http = require('http').Server(app);
const io = require('socket.io')(http);
const path = require('path');
const Watcher = require('./watch2');
let watcher = new Watcher("test.log");
watcher.start();
app.get('/log', (req, res) => {
console.log("request received");
var options = {
root: path.join(__dirname)
};
var fileName = 'index.html';
res.sendFile(fileName, options, function (err) {
if (err) {
next(err);
} else {
console.log('Sent:', fileName);
}
});
})
io.on('connection', function(socket){
// console.log(socket);
console.log("new connection established:"+socket.id);
watcher.on("process", function process(data) {
socket.emit("update-log",data);
});
let data = watcher.getLogs();
socket.emit("init",data);
});
http.listen(3000, function(){
console.log('listening on localhost:3000');
});
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const express = require('express');
const { exec } = require('child_process');
const app = express();
const port = 3000;
// Define browser commands and paths
const browserPaths = {
chrome: {
start: 'google-chrome', // Use 'google-chrome-stable' if installed
stop: 'pkill chrome',
cleanup: 'sudo rm -rf ~/.config/google-chrome/Default/*'
},
firefox: {
start: 'firefox', // Use 'firefox' command
stop: 'pkill firefox',
cleanup: 'sudo rm -rf ~/.mozilla/firefox/*.default-release/'
}
};
// Root route
app.get('/', (req, res) => {
res.send('Welcome to the Browser Service API. Use /start, /stop, /cleanup, or /geturl.');
});
// Start a browser with a specific URL
app.get('/start', (req, res) => {
const { browser, url } = req.query;
if (!browserPaths[browser] || !url) {
return res.status(400).send('Invalid parameters');
}
const startCommand = `${browserPaths[browser].start} ${url}`;
exec(startCommand, (error) => {
if (error) {
return res.status(500).send('Failed to start browser');
}
res.send('Browser started');
});
});
// Stop a browser
app.get('/stop', (req, res) => {
const { browser } = req.query;
if (!browserPaths[browser]) {
return res.status(400).send('Invalid browser');
}
exec(browserPaths[browser].stop, (error) => {
if (error) {
return res.status(500).send('Failed to stop browser');
}
res.send('Browser stopped');
});
});
// Clean up browsing data
app.get('/cleanup', (req, res) => {
const { browser } = req.query;
if (!browserPaths[browser]) {
return res.status(400).send('Invalid browser');
}
exec(browserPaths[browser].cleanup, (error) => {
if (error) {
return res.status(500).send('Failed to clean up browser');
}
res.send('Browser cleaned up');
});
});
app.listen(port, () => {
console.log(`Server running at http://localhost:${port}`);
});
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