We Keep Coding

Get request to a .html file is not handled by express

const express = require('express');
const app = express();
const port = 3000;
const bodyPar=require('body-parser');
const session = require('express-session');
const path=require('path');
var user=["Jared","Bill","Jason","Jeremy"];
app.use(express.static('proiect'));
app.use(bodyPar.urlencoded({extended : true}));
app.use(bodyPar.json());
app.use(session({secret:'secret',saveUninitialized:true,resave:true}));
var sess;
var s;
app.post('/login',function(req,res){
var i=0;
sess=req.session;
var username=req.body.username;
var pass=req.body.password;
var but=req.body.value;
s=0;
sess.email=username;
for(i=0;i<3;i++)
{
if(username==user[i])
{
s=s+1;
i=5;
}
}
if(pass="123")
s=s+1;
if(s==2)
res.redirect('homepage.html');
else
res.redirect('login-error.html');
res.end();
});
app.get('/homepage.html',function(req,res){
console.log('aaa');
});
app.get('bios.html',function(req,res){
console.log('aaa');
});
app.post('/guest',function(req,res){
sess=req.session;
sess.username="Guest";
s=2;
res.redirect('homepage.html');
});
app.get('/logout',function(req,res){
req.session.destroy(function(){
res.redirect('login.html');
s=0;
});
});
app.listen(port, () => console.log(`listening on port ${port}!`));
The server doesnt handle the app.get('homepage.html') or 'bios.html' it just displays the html file in the browser.(should hang and display smth on console).
Am i supposed to serve/render those files instead of directly accessing them in the browser?
Both of those files are in the /proiect/ folder i've included on the server.

Express finds the static HTML file and then returns that to the user. Therefore it skips the route handler you wrote.
If you are trying to perform some server-side logic and returning an HTML page, rather return the page inside your route handler to avoid such side effects. In this case, create your HTML file in a templates folder or something. Then you can put all your static resources in your static folder. So your structure would look something like this:
+ project_folder
+ static
+ css
- style.css
+ js
- app.js
+ templates
- bios.html
- homepage.html
- login.html
- login-error.html
- app.js
Then your app.js would look something like this:
const express = require('express');
const app = express();
const port = 3000;
const bodyPar=require('body-parser');
const session = require('express-session');
const path=require('path');
var user=["Jared","Bill","Jason","Jeremy"];
app.use(express.static('static'));
app.use(bodyPar.urlencoded({extended : true}));
app.use(bodyPar.json());
app.use(session({secret:'secret',saveUninitialized:true,resave:true}));
var sess;
var s;
app.get('/login', function(req, res) {
res.sendFile(path.join(__dirname, '/templates/login.html'));
});
app.post('/login',function(req,res){
var i=0;
sess=req.session;
var username=req.body.username;
var pass=req.body.password;
var but=req.body.value;
s=0;
sess.email=username;
for(i=0;i<3;i++)
{
if(username==user[i])
{
s=s+1;
i=5;
}
}
if(pass="123")
s=s+1;
if(s==2)
res.redirect('homepage');
else
res.redirect('login-error');
res.end();
});
app.get('/homepage',function(req,res){
res.sendFile(path.join(__dirname, '/templates/homepage.html'));
});
app.get('bios',function(req,res){
res.sendFile(path.join(__dirname, '/templates/bios.html'));
});
app.get('login-error', function(req, res) {
res.sendFile(path.join(__dirname, '/templates/login-error.html'));
});
app.post('/guest',function(req,res){
sess=req.session;
sess.username="Guest";
s=2;
res.redirect('homepage');
});
app.get('/logout',function(req,res){
req.session.destroy(function(){
res.redirect('login');
s=0;
});
});
app.listen(port, () => console.log(`listening on port ${port}!`));

How to query in nodejs?

this is my first time asking questions and this is basically my last resort in finding some answers. Im a noob and beginner in javascript so please use simple terms with me.
So i have an issue. I dont know how to query.
- As in do i put all my queries in one script or do i have to split them up to different scripts.
- Right now, i have a server.js and i put all my codes in there. including queries. So how do i run just one of them.
- and also if there is such a thing for me to query for just another number like 4. Do i have to go back to the script to manually change from '110' to '4' or can i just enter it somewhere.
Some examples are:
//length of 110
db.collection.find({length: "110"}, function(err, collection) {
if( err || !collection) console.log("No collections with 110 in length");
else collection.forEach( function(length) {
console.log(length);
} );
});
//shows record of length 110 and length 340
var length = ['110', '340']
length = length.join('|');
var re = new RegExp(length, 'i')
db.collection.find({length:{$regex: re}}, function(err, collection) {
if( err || !collection ) console.log("User not found");
else collection.forEach (function(length){
console.log(length);
});
});
How do i query to only run for one of them in mongodb. Appericiate the help alot guys

You already know that node.js is used for making servers. So there are 2 ways you can query the database. Since you're new to node, I'm going to list both the ways :
1.A http GET for querying data (Standard Way)
You can write a simple http server and set a route for getting the type of data you want.I've written a small file so that you can understand:
var express = require('express');
var http = require('http');
var app = express();
var bodyParser = require('body-parser');
// Db settings
var mongodb = require('mongodb');
var MongoClient = mongodb.MongoClient;
var url = 'mongodb://localhost:27017/my_database_name';
function getConnection(url, callback) {
MongoClient.connect(url, function(dbErr, dbRes) {
if(dbErr) {
return callback(err, null);
}
callback(null, dbRes);
});
}
// Configure app to use bodyparser
app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
var port = process.env.PORT || 7013;
app.set('port', port);
app.use(function(req, res, next) {
console.log(req.ip+ ":"+port + req.url + " "+req.method);
next();
});
app.get('/getCityData', function(req, res, next) {
var cityName = req.query.city;
getConnection(url, function(conErr, db) {
if(conErr) {
return res.send("ERROR IN GETTING connection");
}
var cityCollection = db.collection('cities');
cityCollection.find({"city":cityName}).toArray(function(err, result) {
if(err) return res.send("error in querying data");
db.close();
res.send(result);
});
});
});
var httpServer = http.createServer(app).listen(port, function() {
console.log("Express server listening on port "+app.get('port'));
});
You can query the server using curl or postman like this :
2.Using command line arguments :
You can also do it the easy way using command line arguments by passing the parameter to query, but it's less flexible:
var mongodb = require('mongodb');
var MongoClient = mongodb.MongoClient;
var url = 'mongodb://localhost:27017/my_database_name';
function getConnection(url, callback) {
MongoClient.connect(url, function(dbErr, dbRes) {
if(dbErr) {
return callback(err, null);
}
callback(null, dbRes);
});
}
var cityName = process.argv[2]; // that's the argument you'd receive
getConnection(url, function(conErr, db) {
if(conErr) {
return res.send("ERROR IN GETTING connection");
}
var cityCollection = db.collection('cities');
cityCollection.find({"city":cityName}).toArray(function(err, result) {
if(err) return res.send("error in querying data");
db.close();
console.log(result);
});
});
Pass that commandline argument like this while executing file :
I hope it helps

Cannot read property of undefined Node.js

I'm very new to node.js and I'm having struggle with querying to MySQL DB. This is a very simple web page, all I have to do is read the value from the input and search it on my DB.
The problem is that var num is still undefined when the web page executes the query. How do I guarantee that I get that value before executing the query?
var http = require("http");
var url = require('url');
var fs = require('fs');
var io = require('socket.io');
var express = require('express');
var mysql = require('mysql');
var port = process.env.PORT || 8001;
var router = express.Router();
var app = express();
var server = http.createServer(app);
var n_eleitor;
var nome;
var local;
var num_bi;
var num;
// ---- ROUTES ------
app.get('/', function(req, res) { //homepage
res.sendFile(__dirname+'/index.html');
handle_database(req, res);
});
app.get('/result', function(req, res, next) { //results
res.render('result.ejs', { n_eleitor: n_eleitor, local: local, nome: nome });
});
app.use('/', router);
// ---- CONECTION -----
server.listen(port);
var listener = io.listen(server);
listener.sockets.on('connection', function(socket){
socket.on('client_data', function(data){ //receive data from client
//console.log(data.letter);
num_bi = data.letter;
console.log(num_bi);
var num = "'"+num_bi+"'";
console.log(num);
});
});
// ---- MYSQL ------
var pool = mysql.createPool ({ //pool maitains a cache of database connections -> handles multiple connections
connectionLimit : 100,
host : 'localhost',
user : 'root',
password : 'soraia',
database : 'pti2',
});
function handle_database(req, res) {
pool.getConnection(function(err, connection){
if(err){
connection.release(); //connection returns to the pool, ready to be used again by someone else.
return;
}
//console.log('ID:' + connection.threadId);
connection.query("select eleitor.*, freguesia.designacao from freguesia, eleitor where num_bi= ? and freguesia.cod_freg=eleitor.cod_freg",[num], function(err, rows, fields){
n_eleitor = rows[0].cod_eleitor;
nome = rows[0].nome;
local = rows[0].designacao;
connection.release();
console.log(num);
console.log(rows);
});
});
}
When I run the program I get "TypeError: Cannot read property 'cod_eleitor' of undefined" and I think that's because what I said before...
Can someone help me, please?

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...");
});

how to return a value from express middleware as a separate module

I have put the server setting script into a separate js file called server.js. My problem is that I don't know how to get the value of cookie_key from the express middleware function and pass it back to the index.js file.
server.js:
var express = require('express'),
app = express(),
http = require('http').createServer(app),
cookie = cookieParser = require('cookie-parser'),
url = require('url');
module.exports = {
use_app : function(){
app.use(function (req, res, next) {
var cacheTime = 86400000*7; // 7 days
if (!res.getHeader('Cache-Control'))
res.setHeader('Cache-Control', 'public, max-age=' + (cacheTime / 1000));
next();
});
},
get_app : function(callback){
app.use(cookieParser());
app.get('/id/:tagId', function(req, res){ // parse the url parameter to get the file name
function getkey(err,data){ // get users' session cookie
var cookie_key;
if(err)
{
callback(err);
}
cookie_key = req.cookies["session"];
callback(cookie_key);
}
var filename = req.param("tagId");
res.sendFile(filename+'.html');
});
}
}
index.js:
var server = require('./server'),
server.use_app();
server.get_app(); // how to get the cookie_key when calling this function?
console.log(show_cookie_key_from the module);
if(cookie_key !== undefined)
{
// do something
}
I tried to write a callback function to fetch the cookie key but I don't think it's working.

Update from A.B's answer:
var server = require('./server');
server.use_app();
server.get_app(function(cookie){
if(cookie !== undefined)
{
// do something
}
});
But I still think there is something strange about this setup, what exactly are you trying to accomplish with splitting the app up like this?

Since you are using callback function and that is being poplulated with cookie value , you can get this like following:
var server = require('./server');
server.use_app();
server.get_app(function(cookie){
cookie_key= cookie
if(cookie_key !== undefined)
{
// do something
}
});