res.sendFile is not a function.
The following is my server js code
var app = require('express')();
var http = require('http').Server(app);
var fs = require('fs');
var io = require("socket.io")(http);
var users = {};
app.get('/', function(req, res) {
res.sendFile(__dirname + '/client.html');
});
app.listen(3000)
io.on("connection", function (client) {
client.on("join", function (name) {
users[client.id] = name;
client.emit("update", "Connected to Server");
socket.sockets.emit("update", name + " has entered the confession room");
socket.sockets.emit("update-users", users);
});
client.on("send", function (msg) {
socket.sockets.emit("chat", users[client.id], msg);
});
client.on("disconnect", function () {
socket.sockets.emit("update", users[client.id] + " has left the confession room");
delete users[client.id];
socket.sockets.emit("update-users", users);
});
});
Things I have tried:
- Checking the order of the parameter.
- Installing express module.
You have duplicate servers with these two lines of code and you're passing the one to socket.io that you never start:
var http = require('http').Server(app); // one on port 80
app.listen(3000); // one on port 3000
Remove the first one, then modify your code as shown below. And, make sure you're connecting on port 3000 where the Express server and socket.io severs are.
Or, if you want the server and socket.io to be on port 80, then change to:
const server = app.listen(80);
So, you should end up with this:
const app = require('express')();
const fs = require('fs');
const users = {};
app.get('/', function(req, res) {
res.sendFile(__dirname + '/client.html');
});
const server = app.listen(3000);
const io = require("socket.io")(server);
// various socket.io code here
Related
Given a simple toy example:
var express = require("express");
var app = express();
app.get('/', function(req, res) {
res.redirect("https://www.google.com"); // <-- (*)
console.log("After redirect");
});
var server = app.listen(14000, 'localhost', function() {
var host = server.address().address;
var port = server.address().port;
console.log('Test listening on port 14000.');
});
At the location marked with (*), what happens there? Is a 3XX Status Code returned while the server runs the following statements? Or is the 3xx status code only returned after the block finishes?
Is this handled differently in other frameworks, i.e. Django?
I want to send serial port data to a browser UI with express. So far my code looks like this:
var SerialPort = require("serialport");
var serialport = new SerialPort("/dev/cu.usbmodem1421");
var express = require('express');
var app = express();
var datenFromA;
serialport.on('open', function(){
console.log('Serial Port Opend');
serialport.on('data', function(data){
datenFromA = data[0];
console.log(datenFromA);
});
});
app.get('/', function (req, res) {
res.send('Hello World')
})
app.listen(3000);
Instead of the 'Hello World' I want to send the value of variable datenFromA to the browser. Any ideas how to pass the value to the app.get function?
Thanks in advance.
Essentially you need to wait until you receive an event. Quick dirty example given below:
const SerialPort = require("serialport");
const serialport = new SerialPort("/dev/cu.usbmodem1421");
const express = require('express');
const app = express();
// Only need to do this once.
serialport.on('open', () => console.log('Serial Port Opend'));
app.get('/', async (req, res) => {
const promise = new Promise((resolve, reject) => {
serialport.on('data', (data, err) => {
if (err) {
reject(err);
return;
}
resolve(data[0]);
});
})
const data = await promise;
res.json(data);
})
app.listen(3000);
GET /user/me - sends back 404 (resource not found)
If I change the second '/' to a '_' (i.e GET users_me), then it works.
I have two questions:
1) How to fix it so I can use 'GET /user/me'?
2) It works with an underscore so is there any advantage to using the slash vs. the underscore?
///////////Code
require('./config/config');
const _ = require('lodash');
const express = require('express');
const bodyParser = require('body-parser');
const {ObjectID} = require('mongodb');
//const multer = require('multer');
//const router = express.Router();
var renameKeys = require('rename-keys');
var {mongoose} = require('./db/mongoose');
//var {Todo} = require('./models/todo');
var {User} = require('./models/user');
var {authenticate} = require('./middleware/authenticate');
var app = express();
const port = process.env.PORT;
app.use(bodyParser.json());
// GET users/me
app.get('/users_me', authenticate, (req, res) => {
res.send(req.user);
});
// POST /users -- signing up a new user [how will this handle logging in instead of signing up?]
app.post('/users', (req, res) => {
var body = _.pick(req.body, ['email', 'password']);
var user = new User(body);
user.save().then(() => {
return user.generateAuthToken();
}).then((token) => {
res.header('x-auth', token).send(user);
}).catch((e) => {
res.status(400).send(e);
})
});
app.listen(port, () => {
console.log(`Started up at port ${port}`);
});
module.exports = {app};
First question:
Just change
app.get('/users_me', authenticate, (req, res) => {
res.send(req.user);
});
to
app.get('/users/:me', authenticate, (req, res) => {
res.send(req.user);
});
Then make a Get request:
somehost:someport/users/myusername
Second question:
Routing works just like a file-system:
/path/subpath/
So you can't use an underscore to substitute a slash '/'
INFO: You could pass the id or name (depends on your logic) of the user in the URL of your GET-request:
GET request (in this case to localhost with port 3000):
localhost:3000/users/getuserbyid/20
route:
router.get('/getuserbyid/:id', .....
Hope that helps ;)
I am using expressjs, nedb, and socket.io. Various (non-browser) clients are able to PUT new values into the db successfully. When that happens, I want a message emitted to all browsers connected to the server. I have the following code which is currently not sending a message back to the browser.
// on the server
//***************************************************************
// reachable to the world at http://server/foo
// clients can PUT data into the db
app.put('/foo', jsonParser, function(req, res, next) {
if (!req.body) return res.sendStatus(400);
db.insert(req.body, function (err, newDoc) {
io.sockets.emit('PUT a new value', { added: newDoc._id });
res.send('Success! Find it again with id: ' + newDoc._id);
});
});
// reachable to the world at http://server/
// browser shows a dashboard of events
app.get('/', function(req, res, next) {
// code to serve the dashboard here
});
io.sockets.on('connection', function (socket) {
socket.on('foo', function (data) {
io.sockets.emit('PUT a new value', data);
})
});
// in the browser
//***************************************************************
var socket = io.connect('/');
socket.on('PUT a new value', function (data) {
console.log(data);
});
Data get inserted into the db successfully from different non-browser clients, but the connected browser doesn't receive an update.
What am I doing wrong?
I found a solution which I don't like at all but it works. We can add io object to req or to res in the middleware like that:
app.use(function (req, res, next) {
req.io = io;
next();
});
before app.use('/', routes) and then in our router module we "import" the io object:
app.put('/foo', jsonParser, function(req, res, next) {
if (!req.body) return res.sendStatus(400);
db.insert(req.body, function (err, newDoc) {
var io = req.io; // HERE !!!
io.sockets.emit('PUT a new value', { added: newDoc._id });
res.send('Success! Find it again with id: ' + newDoc._id);
});
});
I know, I know... let's find something else :-)
I have the following app structure generated by express generator. I start the app with $ DEBUG=foo:* npm start
.
|____app.js
|____bin
| |____www
|____data
|____LICENSE
|____node_modules
|____package.json
|____public
| |____stylesheets
| |____javascripts
| |____images
|____README.md
|____routes
| |____index.js
| |____readings.js
| |____sensors.js
| |____users.js
|____views
| |____error.hjs
| |____index.hjs
In app.js
var express = require('express');
var app = express();
var io = require('socket.io')();
app.io = io;
// notice the `(io)` for the routes that need to be socket-aware
var routes = require('./routes/index');
var users = require('./routes/users');
var sensors = require('./routes/sensors');
var readings = require('./routes/readings')(io);
…
// start listening with socket.io
app.io.on('connection', function(socket){
console.log('a user connected');
});
module.exports = app;
Then in ./routes/readings.js
var express = require('express');
var app = express();
var router = express.Router();
module.exports = function(io) {
router.put('/', jsonParser, function(req, res, next) {
if (!req.body) return res.sendStatus(400);
db.insert(req.body, function (err, newDoc) {
io.emit("reading", {id: newDoc._id});
res.send('Success PUTting data! id: ' + newDoc._id);
});
});
return router;
}
Finally, in the index.hjs template for the client-side
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io();
socket.on('reading', function (data) {
console.log(data);
});
</script>
The above works. When data are inserted into the db via an http PUT (see readings.js), an event is emitted by io.emit('reading', data) and the browser receives that event and shows it in the console with socket.on('reading', function (data) { … });
I'm trying to create a really simple node API using express.js 4 but I need a few 'realtime' events for which I added socket.io. I'm fairly new to both so I'm likely missing something basic but I can't find good docs/tuts on this.
In the express app (created with the express generator) I have something like this based on simple examples and project docs that I read. This works OK and from client apps, I can send/receive the socket events:
var express = require('express');
var path = require('path');
var logger = require('morgan');
var api = require('./routes/api');
var app = express();
var io = require('socket.io').listen(app.listen(3000));
app.use(logger('dev'));
app.use(express.static(path.join(__dirname, 'public')));
app.use('/api', api);
io.sockets.on('connection', function (socket) {
console.log('client connect');
socket.on('echo', function (data) {
io.sockets.emit('message', data);
});
});
// error handlers omitted
module.exports = app;
but I want to use the sockets from my API routes (in the ./routes/api.js file that I 'require' above). For example, someone might use the API to PUT/POST a resource and I want that broadcast to connected socket.io clients.
I cannot see how to use the 'io' variable or organise the code currently in the io.sockets.on('connection' ... function inside express routes. Here's the ./routes/api.js file:
var express = require('express');
var router = express.Router();
var io = ???;
router.put('/foo', function(req, res) {
/*
do stuff to update the foo resource
...
*/
// now broadcast the updated foo..
io.sockets.emit('update', foo); // how?
});
module.exports = router;
One option is to pass it in to req object.
app.js:
var express = require('express');
var path = require('path');
var logger = require('morgan');
var api = require('./routes/api');
var app = express();
var io = require('socket.io').listen(app.listen(3000));
app.use(logger('dev'));
app.use(express.static(path.join(__dirname, 'public')));
io.sockets.on('connection', function (socket) {
console.log('client connect');
socket.on('echo', function (data) {
io.sockets.emit('message', data);
});
});
// Make io accessible to our router
app.use(function(req,res,next){
req.io = io;
next();
});
app.use('/api', api);
// error handlers omitted
module.exports = app;
./routes/api.js:
var express = require('express');
var router = express.Router();
router.put('/foo', function(req, res) {
/*
do stuff to update the foo resource
...
*/
// now broadcast the updated foo..
req.io.sockets.emit('update', foo);
});
module.exports = router;
I've modified your files a little bit, may you check if it works?
You can pass the io you've defined to your routes like below;
require('./routes/api')(app,io);
I didn't test the Socket.IO parts but there is no syntax error and routes also working.
server.js file:
var express = require('express');
var app = express();
var path = require('path');
var logger = require('morgan');
var io = require('socket.io').listen(app.listen(3000));
app.use(logger('dev'));
app.use(express.static(path.join(__dirname, 'public')));
io.sockets.on('connection', function (socket) {
console.log('client connect');
socket.on('echo', function (data) {
io.sockets.emit('message', data);
});
});
require('./routes/api')(app,io);
console.log("Server listening at port 3000");
api.js:
module.exports = function(app,io) {
app.put('/foo', function(req, res) {
/*
do stuff to update the foo resource
...
*/
// now broadcast the updated foo..
console.log("PUT OK!");
io.sockets.emit('update'); // how?
res.json({result: "update sent over IO"});
});
}
Supposing you want to access the SocketIO from anywhere in your application, not just in the router, you could create a singleton for it. This is what works for me:
//socket-singletion.js
var socket = require('socket.io');
var SocketSingleton = (function() {
this.io = null;
this.configure = function(server) {
this.io = socket(server);
}
return this;
})();
module.exports = SocketSingleton;
Then, you need to configure it using your server:
//server config file
var SocketSingleton = require('./socket-singleton');
var http = require('http');
var server = http.createServer(app);
SocketSingleton.configure(server); // <--here
server.listen('3000');
Finally, use it wherever you want:
//router/index.js
var express = require('express');
var router = express.Router();
var SocketSingleton = require('../socket-singleton');
/* GET home page. */
router.get('/', function(req, res, next) {
setTimeout(function(){
SocketSingleton.io.emit('news', {msg: 'success!'});
}, 3000);
res.render('index', { title: 'Express' });
});
module.exports = router;
One more option is to use req.app.
app.js
const express = require('express');
const path = require('path');
const logger = require('morgan');
const api = require('./routes/api');
const app = express();
const io = require('socket.io').listen(app.listen(3000));
// Keep the io instance
app.io = io;
app.use(logger('dev'));
app.use(express.static(path.join(__dirname, 'public')));
// ...
app.use('/api', api);
module.exports = app;
routes/api.js
const express = require('express');
const router = express.Router();
router.put('/foo', function(req, res) {
/*
* API
*/
// Broadcast the updated foo..
req.app.io.sockets.emit('update', foo);
});
module.exports = router;
Refactored Edudjr's answer.
Change the singleton to create a new instance of socket.io server
const { Server } = require('socket.io');
const singleton = (() => {
this.configure = (server) => this.io = new Server(server)
return this
})();
module.exports = singleton
Initialise your express app, the server and the singleton.
// initialise app
const app = express();
const server = require('http').createServer(app);
// configure socket.io
socket.configure(server)
Then in your router
const socket = require('/utils/socket-singleton');
socket.io.emit('event', {message: 'your message here'})
I think best way is to set io as a property of req, like below:
app.use(function(req,res,next){
req.io = io;
next();
});
app.use('/your-sub-link', your-router);