We Keep Coding

Trying to capture Client IP Address for already running server in localhost, but node.js conflicts with existing server

I am trying to capture client ipaddress for traffic visiting my localhost:8080. I am using the following modules and the node.js application looks like this
var connect = require('connect');
var http = require('http');
var net = require('net');
var express = require('express');
var app = express();
var app = connect();
// require request-ip and register it as middleware
var requestIp = require('request-ip');
// you can override which attirbute the ip will be set on by
// passing in an options object with an attributeName
app.use(requestIp.mw({ attributeName : 'myCustomAttributeName' }))
// respond to all requests
app.use(function(req, res) {
// use our custom attributeName that we registered in the middleware
var ip = req.myCustomAttributeName;
console.log(ip);
fs.appendFile('iplist.csv', ip, 'utf8', function (err) {
if (err) {
console.log('Some error occured - file either not saved or corrupted file saved');
} else{
console.log('It\'s saved!');
}
});
// https://nodejs.org/api/net.html#net_net_isip_input
// var ipType = net.isIP(ip); // returns 0 for invalid, 4 for IPv4, and 6 for IPv6
// res.end('IP address is ' + ip + ' and is of type IPv' + ipType + '\n');
});
//create node.js http server and listen on port
app.listen(8080);
Is there any way I can listen to the already existing server without creating my own, hence avoiding the conflict of two servers fighting for the same port. I am new to node.js. Any help will be great. Thank you!

Node.js server hangs occasionally

I have this node.js server. The problem is sometimes I notice that it gets stuck. That is the client can make requests, but the server doesn't respond, rather it doesn't end the response, it just gets stuck in the server side. If I look in client side dev tools on the http request, it has a gray circle icon meaning waiting for server response. Even if I wait 10 minutes, nothing happens.
The server side also writes things to console on the requests, which doesn't happen when it gets stuck.
On the node.js console, if I then press ctrl+c when it got stuck, I then suddenly see all the console.log messages just appear on the console, and at the same time, the dev tools, recieves all the responses from the server side, i.e. the gray circle changes to green.
Does anyone know what this problem is?
Thanks
var express = require('express');
var https = require("https");
var fse = require("fs-extra");
var bodyParser = require('body-parser');
// INFO
var root = __dirname + '/public';
setUpServer();
// SET UP SERVER
function setUpServer() {
var app = express();
app.use(express.static(root));
app.use(bodyParser.urlencoded({ extended: false }))
app.get('/', function (req, res) {
var dest = 'index.html';
res.sendFile(dest, { root: root + "/pong" });
});
app.post('/get_brain', function (req, res) {
res.end("1");
console.log('Sent master brain to a client!');
});
app.post('/train_and_get_brain', function (req, res) {
res.end("1");
console.log('Sent master brain to a client!');
});
var privateKey = fse.readFileSync('sslcert/key.pem', 'utf8');
var certificate = fse.readFileSync('sslcert/cert.pem', 'utf8');
var credentials = {key: privateKey, cert: certificate};
var httpsServer = https.createServer(credentials, app);
httpsServer.listen(process.env.PORT || 3000, function () {
var host = httpsServer.address().address;
var port = httpsServer.address().port;
console.log('AI started at https://%s:%s', host, port);
});
}

(crypto.js) TypeError: Data must be string or buffer

I am currently using crypto.js module to hash things. It was working for a while then I started getting this error:
Here is the foundation of my server:
process.stdout.write('\033c'); // Clear the console on startup
var
express = require("express"),
app = express(),
http = require("http").Server(app),
io = require("socket.io")(http),
path = require("path"),
colorworks = require("colorworks").create(),
fs = require("fs"),
crypto = require("crypto");
function md5(msg){
return crypto.createHash("md5").update(msg).digest("base64");
}
function sha256(msg) {
return crypto.createHash("sha256").update(msg).digest("base64");
}
http.listen(443, function(){
// Create the http server so it can be accessed via 127.0.0.1:443 in a web browser.
console.log("NJ project webserver is running on port 443.");
// Notify the console that the server is up and running
});
app.use(express.static(__dirname + "/public"));
app.get("/", function(request, response){
response.sendFile(__dirname + "/public/index.html");
});
I am aware that these functions are creating the problem:
function md5(msg){
return crypto.createHash("md5").update(msg).digest("base64");
}
function sha256(msg) {
return crypto.createHash("sha256").update(msg).digest("base64");
}
The problem being, if these functions don't work (which they don't anymore), roughly 200 lines of code will go to waste.

This error is triggered by attempting to hash a variable that does not exist:
function md5(msg){
return crypto.createHash("md5").update(msg).digest("base64");
}
function sha256(msg) {
return crypto.createHash("sha256").update(msg).digest("base64");
}
md5(non_existent); // This variable does not exist.

What kind of data are you trying to hash ? Where does it come from ?
I would check the value of msg first then I would try :
crypto.createHash('md5').update(msg.toString()).digest('hex');
You could also use these packages instead:
https://www.npmjs.com/package/md5
https://www.npmjs.com/package/js-sha256

middleware not working on connect HTTP server

I am reading Professional Node.js and i'm trying to understand connect HTTP middleware framework. I created a simple middleware that returns a function that replies with a custom test string:
function replyText(text) {
return function(req, res) {
res.end(text);
};
}
module.exports = replyText;
But when i try to use this middleware in a connect server. Node gives me an error:
/Users/socomo22/work/hello_world_app_v2.js:8
var app = connect.createServer(replyText('Hello World!'));
^
TypeError: undefined is not a function
But when i simply use:
var app = connect();
app.listen(8080)
It runs without giving any error. I don't understand whether i'm doing any syntatical mistake. How would i use this simple middleware? This is my connect server file:
var connect = require('connect');
// middlewares
var replyText = require('./reply_text');
var app = connect();
var app = connect.createServer(replyText('Hello World!'));
app.listen(8080, function() {
console.log('listening on 8080 port')
});

As pointed by documentation use use API to mount a middleware and a http module to create an instance of server although you can create an instance just with connect as pointed here.
As pointed by #FranciscoPresencia adding .js extension while you require a your local module is optional.
var replyText = require('./reply_text.js');
So your code should look like this and i tested it. Working as intended
var connect = require('connect')
var http = require('http')
var app = connect();
// middlewares
var replyText = require('./reply_text.js');
app.use(replyText('Hello World!'));
http.createServer(app).listen(8080, function() {
console.log('listening on 8080 port')
});
Note: Try to avoid ports like 8080, 80 etc as its a reserved ports that might be used by other apps. This sometimes may cause node to fail.
Adding the output screenshot for your reference

Here You can start server in this way...
var connect = require('connect');
var http = require('http');
var app = connect();
var replyIN = require('./connetFile.js')
app.use(replyIN('Hello there m back again'));
http.createServer(app).listen(8888,function(){console.log('Server has started');});
And this is your connectFile.js
function replyIN(text){
return function (req, res) {
res.end(text);
};
};
module.exports = replyIN;

Prime the website using Express JS

I really hope to find some answers here as i tried everything by now.
Background:
Overtime we deploy code to web server, we need to do a cache warm up, i.e. access the site and make sure it loads. First load is always the slowest since IIS require to do some manipulations with a new code and cache it.
Task:
Create a page which will a checkbox and a button. Once button is pressed, array of links sent to server. Server visits each link and provides a feedback on time it took to load each page to the user.
Solution:
I am using node JS & express JS on server side. So far i manage to POST array to the server with links, but since i have limited experience with node JS, i can not figure out server side code to work.
Here is a code i got so far (it is bits and pieces, but it gives an idea of my progress). Any help will be greatly appreciated!!!
var express = require("express");
var app = express();
var bodyParser = require('body-parser');
var parseUrlencoded = bodyParser.urlencoded({ extended: false});
var http = require("http");
function siteToPrime(url){
http.get(url, function (http_res) {
// initialize the container for our data
var data = "";
// this event fires many times, each time collecting another piece of the response
http_res.on("data", function (chunk) {
// append this chunk to our growing `data` var
data += chunk;
});
// this event fires *one* time, after all the `data` events/chunks have been gathered
http_res.on("end", function () {
// you can use res.send instead of console.log to output via express
console.log(data);
});
});
};
//Tells express where to look for static content
app.use(express.static('public'));
app.post('/', parseUrlencoded, function(request, response){
var newBlock = request.body;
console.log(Object.keys(newBlock).length);
var key = Object.keys(newBlock)[0];
console.log(newBlock[key]);
siteToPrime("www.google.com");
response.status(201);
});
app.listen(3000, function(){
console.log("Server listening on port 3000...");
});

Assuming that you have access to the array in the post route:
var express = require("express"),
request = require("request"),
app = express();
var start = new Date();
app.use(express.static('public'));
app.use(bodyParser.urlencoded({extended: false}));
function siteToPrime(req, res, urls) {
urls.forEach(function(url)) {
request(url, function(error, res, body) {
if (!error && res.statusCode == 200) {
console.log(url +' : ' + body);
console.log('Request took: ', new Date() - start, 'ms');
}
});
}
res.redirect('/');
};
app.post('/', function(req, res){
var urls = req.body.urls // Array os urls.
siteToPrime(req, res, urls);
});
app.listen(3000, function(){
console.log("Server listening on port 3000...");
});