I'm learning Node js and I'd like to understand why the output or result set is showing twice in the browser (tried with different browsers) and how to fix the issue to show the result set only once.
Here is my sample code :
// JavaScript source code
var express = require('express'); // Web Framework
var app = express();
var sql = require('mssql'); // MS Sql Server client
// Connection string parameters.
const pool = new sql.ConnectionPool({
user: 'myuser',
password: 'password123',
server: 'localhost',
database: 'Sample'
})
var conn = pool;
// Start server and listen on http://localhost:8080/
var server = app.listen(8080, function () {
var host = server.address().address
var port = server.address().port
console.log("app listening at http://%s:%s", host, port)
});
app.get('/groups', function (req, res) {
conn.connect().then (function() {
var request = new sql.Request(conn);
request.query('SELECT TOP 10 * FROM [Sample].[Table1]',function(err, recordset) {
if(err) console.log(err);
res.end(JSON.stringify(recordset)); // Result in JSON format
conn.close();
});
});
})
please advice.
Thanks.
I want to pull a URL from the DB and use it as the proxied URL. However the setup I've come up with initializes a new BrowserSync server for each URL, using incrementing port numbers.
Is there a way to accomplish this without initializing a new BrowserSync server every time?
Or should I be using another approach?
var bs = require("browser-sync");
var express = require("express");
var router = express.Router();
var app = express();
router.get("/", function(req, res){
var proxyUrl = getUrl() //get url from db (www.example.com)
bs.create("bs1").init({
notify: false,
open: false,
ui: false,
port: 10000,
proxy: proxyUrl
});
res.send();
});
app.use(router);
app.listen(8080, function(){
console.log('listening on *:8080');
});
The above is fine(ish) but is it good practice to be initializing a new server for every URL (potentially thousands)?
And is it safe to be exposing a new port number to every user of the system? (Can I mask this with a subdomain?)
Update
My end goal is to use a unique subdomain to refer to each proxy url.
For example:
sub1.mysite.com proxies www.example.com,
sub2.mysite.com proxies www.example2.com
Browser-sync will not work as the proxy is tie to server setup.
I use following packages:
express
express-http-proxy
vhost (express vhost)
const port = 8080;
var app = require('express')();
var proxy = require('express-http-proxy');
var url = require('url');
var vhost = require('vhost');
app.listen(port);
/* Assuming getUrl() will return an array of sites */
// var sites = getUrl();
// DO NOT put '/' at the end of site
var sites = [
'http://www.bing.com',
'http://samanthagooden.com',
'http://www.courtleigh.com'
];
var i = 0;
sites.forEach(site => {
i++;
var subDomain = 'sub' + i + '.mysite.com';
app.use(vhost(subDomain, proxy(site, {
forwardPath: (req, res) => url.parse(req.url).path,
intercept: (rsp, data, req, res, callback) => {
if (res._headers['content-type']) {
var contentType = res._headers['content-type'];
if (
contentType.indexOf('text') !== -1 ||
contentType.indexOf('javascript') !== -1
) {
// Replace link if content-type = text or javascript
var reg = new RegExp(site, 'g');
res.send(data.toString().replace(reg, ''));
} else {
res.send(data);
}
} else {
res.send(data);
}
}
})));
console.log(subDomain + ':' + port + ' proxy: ' + site);
});
The above example will create following proxies:
sub1.mysite.com:8080 proxy: www.bing.com
sub2.mysite.com:8080 proxy: www.example.com
Maybe I'm misunderstanding what you are trying to do, but Browsersync and express seems a bit overkill in this case, why not just use node-http-proxy with the native http module?
var http = require('http')
var httpProxy = require('http-proxy')
var options = ...
var proxy = httpProxy.createProxyServer(options)
var server = http.createServer(function (req, res) {
var proxyUrl = getUrl()
proxy.web(req, res, { target: proxyUrl })
})
server.listen(8080, function () {
console.log('listening on *:8080')
})
As per me If you want SAAS service using proxy is not the good idea to go is what am thinking.. if you are going with proxy for each client will create process with new port... My Solution is to create node server with listen localhost and map *.domain.com to the server..
If you are using individual database for each client :-
in node logic get cname from request host and use that reference to connect database.
Final Controller code would be..
var express = require('express');
var router = express.Router();
var MongoClient = require('mongodb').MongoClient;
/* GET home page. */
router.get('/', function(req, res, next) {
var client = req.subdomains[0];
console.log(client);
MongoClient.connect('mongodb://localhost:27017/'+client, function(err, db) {
if (err) {
throw err;
}
db.collection('app1').find().toArray(function(err, result) {
if (err) {
throw err;
}
console.log('data');
console.log(result);
});
});
res.render('index', { title: 'Express' });
});
module.exports = router;
~
~
In future if you get more clients you can implement node cluster or standard Ubuntu cluster using webservice
I am using swagger-express-mw NPM package for creating REST services, when I run the project with "swagger project start" then it publishes the APIs over HTTP, how can I use HTTPS instead.
I have used HTTPS using vanilla npm packages as below:
var fs = require('fs');
var https = require('https');
var app = require('express')();
var options = {
key : fs.readFileSync('my.private.key'),
cert : fs.readFileSync('my.certificate.cer')
};
app.get('/', function (req, res) {
res.send('Yuhooo! Response over HTTPS!!! ');
});
https.createServer(options, app).listen(8443, function () {
console.log('Server started # 8443!');
});
But I am not sure how to achieve the same with swagger-express-mw, Below is the code snippet from my app.js which starts the listener. Not getting any option to use HTTPS as the protocol here
SwaggerExpress.create(configuration, function(err, swaggerExpress) {
if (err) { throw err; }
// install middleware
swaggerExpress.register(app);
var port = config.get('server.port') || process.env.PORT || 8080;
app.listen(port);
console.log('Server started at port %d', port);
});
var swaggerDoc = jsYaml.load(fs.readFileSync('./api/swagger/swagger.yaml'));
// Initialize the Swagger middleware for the api doc purpose
swaggerTools.initializeMiddleware(swaggerDoc, function (middleware) {
// Serve the Swagger documents and Swagger UI
app.use(middleware.swaggerUi());
});
app.listen is simply a shortcut you can use
SwaggerExpress.create(configuration, function(err, swaggerExpress) {
if (err) { throw err; }
// install middleware
swaggerExpress.register(app);
var port = process.env.PORT || 443;
https.createServer(options, app).listen(port, function () {
console.log('Server started # %s!', port);
});
});
Using Swagger 2.0 spec with middleware your swagger configuration file can be set to only accept certain schemes:
# Schemes is statically set here but will be overridden in app.js with
swagger object
schemes:
- https
You can review the specification and go to Fixed Fields: http://swagger.io/specification/
I have installed Cubian OS on my Cubieboard.
Then I installed node.js and mongoDB using this tutorial.
It seems node.js is working properly. I can start mongod service but I have several problems:
I cannot execute mongo shell: command not found
localhost:27017 (same as http://127.0.0.1:27017/ is unavailabe)
I cannot connect to mongoDB in my node.js code
npm install produce a lots of errors and I can't install required modules using this command (but I still can use nmp install module_name command)
My test node.js code:
var express = require('express');
// Mongoose import
var mongoose = require('mongoose');
var db = mongoose.connection;
db.on('error', console.error);
db.once('open', function() {
// Create your schemas and models here.
console.log('Connected');
});
// Mongoose connection to MongoDB (ted/ted is readonly)
mongoose.connect('mongodb://127.0.0.1:27017/test', function (error) {
if (error) {
console.log(error);
}
});
// Mongoose Schema definition
var Schema = mongoose.Schema;
var UserSchema = new Schema({
first_name: String,
last_name: String,
email: String
});
// Mongoose Model definition
var User = mongoose.model('users', UserSchema);
// Bootstrap express
var app = express();
// URLS management
app.get('/', function (req, res) {
res.send("<a href='/users'>Show Users</a>");
});
app.get('/users', function (req, res) {
User.find({}, function (err, docs) {
res.json(docs);
});
});
app.get('/users/:email', function (req, res) {
if (req.params.email) {
User.find({ email: req.params.email }, function (err, docs) {
res.json(docs);
});
}
});
// Start the server
var server = app.listen(3000, function () {
var host = server.address().address
var port = server.address().port
console.log('Example app listening at http://%s:%s', host, port)
});
When I execute sudo node server.js command I get following:
Example app listening at http://0.0.0.0:3000
[Error: failed to connect to [127.0.0.1:27017]]
As you can see the IP address is incorrect and localhost:3000 (127.0.0.1:3000) is unavailable too.
Does anyone can help me?
Thanks!
I've added the following lines to /etc/network/interfaces and after that my web-site became available:
auto lo
iface lo inet loopback
I'm using Node & Express 4.0 deployed on Heroku, and I'm trying to implement Socket.io with Redis as aa session store. So I have this as my current code:
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io').listen(server);
var RedisStore = io.RedisStore;
if (process.env.REDISTOGO_URL) {
// inside if statement
var rtg = require("url").parse(process.env.REDISTOGO_URL);
var redis = require("redis").createClient(rtg.port, rtg.hostname);
redis.auth(rtg.auth.split(":")[1]);
} else {
var redis = require("redis").createClient();
}
/** Initialize RedisStore for socket.io **/
io.set('store', new RedisStore({
redis : redis
}));
But I get the following error:
14:25:03 web.1 | io.set('store', new RedisStore({
14:25:03 web.1 | ^
14:25:03 web.1 | TypeError: undefined is not a function
I've also seen this way of defining a RedisStore:
var redis = require('socket.io/node_modules/redis');
var RedisStore = require('socket.io/lib/stores/redis');
However, my installed version of socket.io, installed using npm install --save socket.io, doesn't include stores in the lib directory:
EDIT
I saw this on the socket.io page in regards to their 1.0 release:
// 2. Implement the socket.io-redis adapter
var io = require('socket.io')(3000);
var redis = require('socket.io-redis');
io.adapter(redis({ host: 'localhost', port: 6379 }));
But there's no other documentation I could find regarding this new module, and since I'm new to this whole stack, I don't think I could figure it out on my own.
The trend among node.js modules is to remove functionality that isn't truly core to the module.
Which is why socket.io 1.0 no longer supports redis out of the box.
So step one is to track down the functionality you need.
http://socket.io/docs/server-api/
https://github.com/Automattic/socket.io-adapter
https://github.com/Automattic/socket.io-redis
Then you need to install the other module npm install socket.io-redis --save
And finally configure your app.
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io').listen(server);
var redis = require('socket.io-redis');
io.adapter(redis(process.env.REDISTOGO_URL));
The nice part is the socket.io-redis adapter accepts redis urls and defaults to localhost:6379 so you (should) be able to simple pass in the REDISTOGO_URL
I had to parse libraries above to get this example, so I figured I would post a full blown example, but I must admit there are a couple of things off, this uses REDISCLOUD, it is on Heroku, it does work. I'll post this elsewhere and maybe put it in a doc too.
var redis = require('redis');
var ioredis = require('socket.io-redis'); //Adapter
var url = require('url');
var redisURL = url.parse(process.env.REDISCLOUD_URL );
var pub = redis.createClient(redisURL.port, redisURL.hostname, {return_buffers: true});
var sub = redis.createClient(redisURL.port, redisURL.hostname, {return_buffers: true});
pub.auth(redisURL.auth.split(":")[1]);
sub.auth(redisURL.auth.split(":")[1]);
var redisOptions = {
pubClient: pub,
subClient: sub,
host: redisURL.hostname,
port: redisURL.port
};
io.adapter(ioredis(redisOptions));
Following code works for me with Heroku Redis, hope this helps.
var app = express();
var server = require('http').Server(app);
var io = require('socket.io')(server);
var redis = require('redis');
var redisAdapter = require('socket.io-redis');
io.adapter(redisAdapter({
pubClient: redis.createClient(process.env.REDIS_URL, {return_buffers: true}),
subClient: redis.createClient(process.env.REDIS_URL, {return_buffers: true})
}));
For the ones interested,
this is my prototype chat server running on newest socket.io with express, multiple cores and redis as an intermediate.
Broadcasted messages are send to all room users no matter if they are connected to a different node and port instance.
Just run
node server.js
and on other machines
node client.js
or for testing node client.js 7001, 7002, 7003 ......
server.js
var options = {
//workers: 2, // total workers (default: cpu cores count).
first_port: 7000, // 8000, 8001 are worker's ports (default: 8000).
proxy_port: 5000, // default (5000).
session_hash: function (req, res) { return req.connection.remoteAddress; },
no_sockets: false // allow socket.io proxy (default: false).
};
require('sticky-socket-cluster')(options, start);
function start(port) {
// requirements
var express = require('express');
var http = require('http');
var socketio = require('socket.io');
var path = require('path');
var sticky = require('sticky-session');
var app = express();
var server = http.createServer(app);
var io = socketio.listen(server);
var redis = require('socket.io-redis');
io.adapter(redis({ host: 'localhost', port: 6379 }));
server.listen(port, function() {
console.log(' - listening on ' + port+ ' ' + __dirname);
});
// require our chatserver
var ChatServer = require('./chatserver');
// initialize a new chat server.
new ChatServer({io: io, port: port}).init();
}
chatserver.js
RoomUtil = (function(){
roomMessages = {};
return {
getMessages : function(room_id,limit,cb){
//TODO
cb(roomMessages[room_id] || []);
},
postMessage : function(message,room_id,cb){
if (!roomMessages[room_id]) roomMessages[room_id] = [];
roomMessages[room_id].push(message);
cb();
}
}
})();
var Server = function(options) {
var self = this;
self.io = options.io;
// users array
self.users = [];
// initialize function
self.init = function() {
console.log("init");
// Fired upon a connection
self.io.on('connection', function(socket) {
console.log("incoming connection");
// var ru = new RoomUser();
self.handleConnection(socket,options.port);
});
}
// socket handler for an incoming socket
self.handleConnection = function(socket,port) {
// wait for a login message
socket.emit("incoming connection",{});
socket.on("joinroom",function(data,joinroom_callback){
console.log("attempt to join room ",data.room_id," on port ",port);
if (!data.room_id){
console.log("cannon join room -> no room id given");
return socket.disconnect();
}
else{
var room_id = data.room_id;
socket.join(room_id,function(){
console.log(socket.rooms);
RoomUtil.getMessages(data.room_id,50,function(messages){
console.log("client succesfully joined room ",data.room_id);
joinroom_callback(null,{'messages':messages});
});
socket.on("login",function(data,login_callback){
if (!data.username){
login_callback("invalid userdata",null);
}
else{
login_callback(null,1);
socket.on("post_message",function(data,message_callback){
if (!data.message || data.message == ""){
console.log("empty message posted. ignore");
message_callback("invalid_message",null);
}
else{
console.log("received message on port ",port,data.message);
message_callback(null,1);
RoomUtil.postMessage(data.message,room_id,function(){
RoomUtil.getMessages(room_id,50,function(messages){
console.log("emit messages to room id ",room_id);
//socket.to(room_id).emit('update_messages', messages);
//socket.broadcast.to(room_id).emit('update_messages', messages);
//socket.broadcast.to(room_id).emit('update_messages', messages);
//self.io.to(room_id).emit('update_messages', messages);
self.io.in(room_id).emit('update_messages', messages);
});
})
}
});
}
});
});
}
});
}
}
module.exports = Server;
client.js
var servercon = 'http://localhost:'+(process.argv[2] || 5000);
console.log("going to connect to "+servercon)
var socket = require('socket.io-client')(servercon);
var readline = require('readline');
var rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
socket.on('connect', function(){
console.log("connected, going to login");
socket.emit("joinroom",{"room_id":123123}, function(error,data){
if (error){
console.log("cannot join room ",error);
}
else{
console.log("succesfully joined room -> going to login now");
console.log("received messages count",data.messages.length);
socket.emit("login",{username:"John Mckain"}, function(error, message){
if (error){
console.log("error logging in ",error);
}
else{
console.log("logged in succesfully -> post message now");
var readline = function(){
rl.question("type in a message -> ", function(message) {
socket.emit("post_message",{'message':message}, function(error, message){
if (error){
console.log("error posting message");
readline();
}
else{
console.log("succesfully posted message");
readline();
}
});
});
}
readline();
}
});
socket.on("update_messages",function(data){
console.log("received new messages count ",data.length,data);
});
}
});
});
socket.on('event', function(data){
console.log("event send",data);
});
socket.on('disconnect', function(e){
console.log("disconnected",e);
});
socket.on("welcome",function(data){
console.log("on welcome ",data)
})
socket.on("pong",function(e){
console.log("pong")
})