Lightweight long polling module for express.js
Sets up basic long poll with subscribe and publish functionality.
$ npm install -S express-longpoll
Basic initalization
var express = require('express');
var app = express();
var longpoll = require("express-longpoll")(app)
// You can also enable debug flag for debug messages
var longpollWithDebug = require("express-longpoll")(app, { DEBUG: true });Quick-start code
Server - server.js
var express = require('express');
var app = express();
var longpoll = require("express-longpoll")(app);
// Creates app.get("/poll") for the long poll
longpoll.create("/poll");
app.listen(8080, function() {
console.log("Listening on port 8080");
});
var data = { text: "Some data" };
// Publishes data to all clients long polling /poll endpoint
// You need to call this AFTER you make a GET request to /poll
longpoll.publish("/poll", data);
// Publish every 5 seconds
setInterval(function () {
longpoll.publish("/poll", data);
}, 5000);Client - index.js (with jQuery)
var poll = function () {
$.ajax({
url: "localhost:8080/poll",
success: function(data){
console.log(data); // { text: "Some data" } -> will be printed in your browser console every 5 seconds
poll();
},
error: function() {
poll();
},
timeout: 30000 // 30 seconds
});
};
// Make sure to call it once first,
poll();###longpoll.create(url, [options])
Sets up an express endpoint using the URL provided.
var longpoll = require("express-longpoll")(app);
longpoll.create("/poll");
longpoll.create("/poll2", { maxListeners: 100 }); // set max listeners###longpoll.create(url, middleware, [options])
Set up an express endpoint using the URL provided, and use middleware.
var longpoll = require("express-longpoll")(app);
longpoll.create("/poll", function (req,res,next) {
// do something
next();
});###longpoll.publish(url, data)
Publishes data to all listeners on the url provided.
var express = require('express');
var app = express();
var longpoll = require("express-longpoll")(app);
longpoll.create("/poll");
longpoll.publish("/poll", {});
longpoll.publish("/poll", { hello: "Hello World!" });
longpoll.publish("/poll", jsonData);###longpoll.publishToId(url, id, data)
Publish data to a specific request. See the basic example on how to use this effectively.
var express = require('express');
var router = express.Router();
// with router
var longpoll = require("express-longpoll")(router);
longpoll.create("/routerpoll");
router.get("/", (req, res) => {
longpoll.publish("/routerpoll", {
text: "Some data"
});
res.send("Sent data!");
});
module.exports = router;server.js - create here
var longpoll = require("express-longpoll")(app);
longpoll.create("/poll");route.js - use here
var longpoll = require("express-longpoll")(router);
// Can publish to any endpoint
longpoll.publish("/poll");longpoll.create("/poll")
.then(() => {
console.log("Created /poll");
})
.catch((err) => {
console.log("Something went wrong!", err);
});
longpoll.publish("/poll", data)
.then(() => {
console.log("Published to /poll:", data);
})
.catch((err) => {
console.log("Something went wrong!", err);
});###Client using jQuery
var subscribe = function(url, cb) {
$.ajax({
method: 'GET',
url: url,
success: function(data) {
cb(data);
},
complete: function() {
setTimeout(function() {
subscribe(url, cb);
}, 1000);
},
timeout: 30000
});
};
subscribe("/poll", function (data) {
console.log("Data:", data);
});
subscribe("/poll2", function (data) {
console.log("Data:", data);
});
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