Mixing
What is happening when require(“http”).Server() is evaluated with an Express app as its argument?
4
I was reading the Socket.io Chat Demo here: http://socket.io/get-started/chat/
and I got confused when looking at their require statements.
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('a user connected');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
Am I correct in thinking that require("express") produces an executable Express function (with all of the necessary functions and fields that go with that), and that require("http").Server(app) creates a http.Server object with all of its fields and functions.
If so, I am confused because Express creates a server when we call the .listen function so it seems redundant and backwards to pass an Express app to an http module server.
So, my question is, what is really happening here?
javascript node.js express
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
add a comment |
4
I was reading the Socket.io Chat Demo here: http://socket.io/get-started/chat/
and I got confused when looking at their require statements.
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('a user connected');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
Am I correct in thinking that require("express") produces an executable Express function (with all of the necessary functions and fields that go with that), and that require("http").Server(app) creates a http.Server object with all of its fields and functions.
If so, I am confused because Express creates a server when we call the .listen function so it seems redundant and backwards to pass an Express app to an http module server.
So, my question is, what is really happening here?
javascript node.js express
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.requireis just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.
– adeneo
Dec 15 '14 at 20:01
ExpressJS'app.listen()is just for convenience for simple applications. It useshttp.Server(app), or ratherhttp.createServer(app);, itself.
– Jonathan Lonowski
Dec 15 '14 at 20:36
add a comment |
4
4
4
1
I was reading the Socket.io Chat Demo here: http://socket.io/get-started/chat/
and I got confused when looking at their require statements.
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('a user connected');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
Am I correct in thinking that require("express") produces an executable Express function (with all of the necessary functions and fields that go with that), and that require("http").Server(app) creates a http.Server object with all of its fields and functions.
If so, I am confused because Express creates a server when we call the .listen function so it seems redundant and backwards to pass an Express app to an http module server.
So, my question is, what is really happening here?
javascript node.js express
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
I was reading the Socket.io Chat Demo here: http://socket.io/get-started/chat/
and I got confused when looking at their require statements.
var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);
app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
console.log('a user connected');
});
http.listen(3000, function(){
console.log('listening on *:3000');
});
Am I correct in thinking that require("express") produces an executable Express function (with all of the necessary functions and fields that go with that), and that require("http").Server(app) creates a http.Server object with all of its fields and functions.
If so, I am confused because Express creates a server when we call the .listen function so it seems redundant and backwards to pass an Express app to an http module server.
So, my question is, what is really happening here?
javascript node.js express
javascript node.js express
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
edited Dec 15 '14 at 20:14
Alex Booth
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
asked Dec 15 '14 at 19:59
Alex BoothAlex Booth
3316
3316
You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.requireis just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.
– adeneo
Dec 15 '14 at 20:01
ExpressJS'app.listen()is just for convenience for simple applications. It useshttp.Server(app), or ratherhttp.createServer(app);, itself.
– Jonathan Lonowski
Dec 15 '14 at 20:36
add a comment |
You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.requireis just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.
– adeneo
Dec 15 '14 at 20:01
ExpressJS'app.listen()is just for convenience for simple applications. It useshttp.Server(app), or ratherhttp.createServer(app);, itself.
– Jonathan Lonowski
Dec 15 '14 at 20:36
You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.
require is just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.– adeneo
Dec 15 '14 at 20:01
You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.
require is just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.– adeneo
Dec 15 '14 at 20:01
ExpressJS'
app.listen() is just for convenience for simple applications. It uses http.Server(app), or rather http.createServer(app);, itself.– Jonathan Lonowski
Dec 15 '14 at 20:36
ExpressJS'
app.listen() is just for convenience for simple applications. It uses http.Server(app), or rather http.createServer(app);, itself.– Jonathan Lonowski
Dec 15 '14 at 20:36
add a comment |
2 Answers
2
active
oldest
votes
2
The http server expects a function which has the following signature:
function(req, res)
require('express')(); will create a function with that signature which handles all the magic that express makes available like routing, middleware, etc. Express can create it's own http server instance, but since you're also using socket.io (which expects access to the http server as well), you'll need a separate http instance.
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
In fact Express.listen()returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.
– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variableapppersist within bothhttpandio? It seems like it would have to for routing instructions to work.
– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:appis a function.apphas methods of its own, so it didn't look like a function, and everything I read suggested thathttp.createServer(app)needed a function.
– Michael Lewis
Sep 12 '17 at 10:14
add a comment |
1
var app = require('express')(); //infact, app is a requestListener function.
var http = require('http').Server(app); // infact, function Server eqs http.createServer;
// infact,app.listen eqs http.listen
other code from nodejs and express model
we can see, require("express")() return app is a function.
//express/lib/express.js https://github.com/strongloop/express/blob/master/lib/express.js
var proto = require('./application');
exports = module.exports = createApplication;
function createApplication() {
var app = function(req, res, next) {
app.handle(req, res, next);
};
mixin(app, EventEmitter.prototype, false);
mixin(app, proto, false);
app.request = { __proto__: req, app: app };
app.response = { __proto__: res, app: app };
app.init();
return app;
}
we can see, node.createServer eqs Server
//nodejs/lib/http.js https://github.com/nodejs/node/blob/master/lib/http.js
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
we can see, express app.listen eqs http.listen
//express/lib/application.js https://github.com/strongloop/express/blob/master/lib/application.js
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
//nodejs/lib/_http_server.js https://github.com/nodejs/node/blob/master/lib/_http_server.js
function Server(requestListener) {
if (!(this instanceof Server)) return new Server(requestListener);
net.Server.call(this, { allowHalfOpen: true });
if (requestListener) {
this.addListener('request', requestListener);
}
this.httpAllowHalfOpen = false;
this.addListener('connection', connectionListener);
this.addListener('clientError', function(err, conn) {
conn.destroy(err);
});
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
2
The http server expects a function which has the following signature:
function(req, res)
require('express')(); will create a function with that signature which handles all the magic that express makes available like routing, middleware, etc. Express can create it's own http server instance, but since you're also using socket.io (which expects access to the http server as well), you'll need a separate http instance.
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
In fact Express.listen()returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.
– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variableapppersist within bothhttpandio? It seems like it would have to for routing instructions to work.
– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:appis a function.apphas methods of its own, so it didn't look like a function, and everything I read suggested thathttp.createServer(app)needed a function.
– Michael Lewis
Sep 12 '17 at 10:14
add a comment |
2
The http server expects a function which has the following signature:
function(req, res)
require('express')(); will create a function with that signature which handles all the magic that express makes available like routing, middleware, etc. Express can create it's own http server instance, but since you're also using socket.io (which expects access to the http server as well), you'll need a separate http instance.
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
In fact Express.listen()returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.
– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variableapppersist within bothhttpandio? It seems like it would have to for routing instructions to work.
– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:appis a function.apphas methods of its own, so it didn't look like a function, and everything I read suggested thathttp.createServer(app)needed a function.
– Michael Lewis
Sep 12 '17 at 10:14
add a comment |
2
2
2
The http server expects a function which has the following signature:
function(req, res)
require('express')(); will create a function with that signature which handles all the magic that express makes available like routing, middleware, etc. Express can create it's own http server instance, but since you're also using socket.io (which expects access to the http server as well), you'll need a separate http instance.
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
The http server expects a function which has the following signature:
function(req, res)
require('express')(); will create a function with that signature which handles all the magic that express makes available like routing, middleware, etc. Express can create it's own http server instance, but since you're also using socket.io (which expects access to the http server as well), you'll need a separate http instance.
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
answered Dec 15 '14 at 20:04
Timothy StrimpleTimothy Strimple
18.5k45670
18.5k45670
In fact Express.listen()returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.
– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variableapppersist within bothhttpandio? It seems like it would have to for routing instructions to work.
– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:appis a function.apphas methods of its own, so it didn't look like a function, and everything I read suggested thathttp.createServer(app)needed a function.
– Michael Lewis
Sep 12 '17 at 10:14
add a comment |
In fact Express.listen()returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.
– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variableapppersist within bothhttpandio? It seems like it would have to for routing instructions to work.
– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:appis a function.apphas methods of its own, so it didn't look like a function, and everything I read suggested thathttp.createServer(app)needed a function.
– Michael Lewis
Sep 12 '17 at 10:14
In fact Express
.listen() returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.– hobbs
Dec 15 '14 at 20:14
In fact Express
.listen() returns the server, so you can get access to it that way, but then you would be accepting connections before socketio could do its thing.– hobbs
Dec 15 '14 at 20:14
@Timothy: so does the variable
app persist within both http and io? It seems like it would have to for routing instructions to work.– Alex Booth
Dec 15 '14 at 20:15
@Timothy: so does the variable
app persist within both http and io? It seems like it would have to for routing instructions to work.– Alex Booth
Dec 15 '14 at 20:15
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
express and socket.io override plug into the http server in different ways. For the most part, express just creates a middleware chain to pass the request / response through which will build up the response. Socket.io needs to plugin in front of that to ensure that its websocket upgrade requests aren't corrupted by any express middleware. Socket.io removes all the existing http handlers from the server, then only passes requests to express if it doesn't handle the request itself. See the implementation here: github.com/Automattic/engine.io/blob/master/lib/server.js#L342
– Timothy Strimple
Dec 15 '14 at 20:26
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
@TimothyStrimple: Thanks for the explanation--I think I've got some research to do on JS itself, but your answer helped me to much better understand what was going on in the case.
– Alex Booth
Dec 16 '14 at 0:17
The major confusion point for me:
app is a function. app has methods of its own, so it didn't look like a function, and everything I read suggested that http.createServer(app) needed a function.– Michael Lewis
Sep 12 '17 at 10:14
The major confusion point for me:
app is a function. app has methods of its own, so it didn't look like a function, and everything I read suggested that http.createServer(app) needed a function.– Michael Lewis
Sep 12 '17 at 10:14
add a comment |
1
var app = require('express')(); //infact, app is a requestListener function.
var http = require('http').Server(app); // infact, function Server eqs http.createServer;
// infact,app.listen eqs http.listen
other code from nodejs and express model
we can see, require("express")() return app is a function.
//express/lib/express.js https://github.com/strongloop/express/blob/master/lib/express.js
var proto = require('./application');
exports = module.exports = createApplication;
function createApplication() {
var app = function(req, res, next) {
app.handle(req, res, next);
};
mixin(app, EventEmitter.prototype, false);
mixin(app, proto, false);
app.request = { __proto__: req, app: app };
app.response = { __proto__: res, app: app };
app.init();
return app;
}
we can see, node.createServer eqs Server
//nodejs/lib/http.js https://github.com/nodejs/node/blob/master/lib/http.js
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
we can see, express app.listen eqs http.listen
//express/lib/application.js https://github.com/strongloop/express/blob/master/lib/application.js
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
//nodejs/lib/_http_server.js https://github.com/nodejs/node/blob/master/lib/_http_server.js
function Server(requestListener) {
if (!(this instanceof Server)) return new Server(requestListener);
net.Server.call(this, { allowHalfOpen: true });
if (requestListener) {
this.addListener('request', requestListener);
}
this.httpAllowHalfOpen = false;
this.addListener('connection', connectionListener);
this.addListener('clientError', function(err, conn) {
conn.destroy(err);
});
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
add a comment |
1
var app = require('express')(); //infact, app is a requestListener function.
var http = require('http').Server(app); // infact, function Server eqs http.createServer;
// infact,app.listen eqs http.listen
other code from nodejs and express model
we can see, require("express")() return app is a function.
//express/lib/express.js https://github.com/strongloop/express/blob/master/lib/express.js
var proto = require('./application');
exports = module.exports = createApplication;
function createApplication() {
var app = function(req, res, next) {
app.handle(req, res, next);
};
mixin(app, EventEmitter.prototype, false);
mixin(app, proto, false);
app.request = { __proto__: req, app: app };
app.response = { __proto__: res, app: app };
app.init();
return app;
}
we can see, node.createServer eqs Server
//nodejs/lib/http.js https://github.com/nodejs/node/blob/master/lib/http.js
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
we can see, express app.listen eqs http.listen
//express/lib/application.js https://github.com/strongloop/express/blob/master/lib/application.js
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
//nodejs/lib/_http_server.js https://github.com/nodejs/node/blob/master/lib/_http_server.js
function Server(requestListener) {
if (!(this instanceof Server)) return new Server(requestListener);
net.Server.call(this, { allowHalfOpen: true });
if (requestListener) {
this.addListener('request', requestListener);
}
this.httpAllowHalfOpen = false;
this.addListener('connection', connectionListener);
this.addListener('clientError', function(err, conn) {
conn.destroy(err);
});
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
add a comment |
1
1
1
var app = require('express')(); //infact, app is a requestListener function.
var http = require('http').Server(app); // infact, function Server eqs http.createServer;
// infact,app.listen eqs http.listen
other code from nodejs and express model
we can see, require("express")() return app is a function.
//express/lib/express.js https://github.com/strongloop/express/blob/master/lib/express.js
var proto = require('./application');
exports = module.exports = createApplication;
function createApplication() {
var app = function(req, res, next) {
app.handle(req, res, next);
};
mixin(app, EventEmitter.prototype, false);
mixin(app, proto, false);
app.request = { __proto__: req, app: app };
app.response = { __proto__: res, app: app };
app.init();
return app;
}
we can see, node.createServer eqs Server
//nodejs/lib/http.js https://github.com/nodejs/node/blob/master/lib/http.js
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
we can see, express app.listen eqs http.listen
//express/lib/application.js https://github.com/strongloop/express/blob/master/lib/application.js
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
//nodejs/lib/_http_server.js https://github.com/nodejs/node/blob/master/lib/_http_server.js
function Server(requestListener) {
if (!(this instanceof Server)) return new Server(requestListener);
net.Server.call(this, { allowHalfOpen: true });
if (requestListener) {
this.addListener('request', requestListener);
}
this.httpAllowHalfOpen = false;
this.addListener('connection', connectionListener);
this.addListener('clientError', function(err, conn) {
conn.destroy(err);
});
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
var app = require('express')(); //infact, app is a requestListener function.
var http = require('http').Server(app); // infact, function Server eqs http.createServer;
// infact,app.listen eqs http.listen
other code from nodejs and express model
we can see, require("express")() return app is a function.
//express/lib/express.js https://github.com/strongloop/express/blob/master/lib/express.js
var proto = require('./application');
exports = module.exports = createApplication;
function createApplication() {
var app = function(req, res, next) {
app.handle(req, res, next);
};
mixin(app, EventEmitter.prototype, false);
mixin(app, proto, false);
app.request = { __proto__: req, app: app };
app.response = { __proto__: res, app: app };
app.init();
return app;
}
we can see, node.createServer eqs Server
//nodejs/lib/http.js https://github.com/nodejs/node/blob/master/lib/http.js
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
we can see, express app.listen eqs http.listen
//express/lib/application.js https://github.com/strongloop/express/blob/master/lib/application.js
app.listen = function listen() {
var server = http.createServer(this);
return server.listen.apply(server, arguments);
};
//nodejs/lib/_http_server.js https://github.com/nodejs/node/blob/master/lib/_http_server.js
function Server(requestListener) {
if (!(this instanceof Server)) return new Server(requestListener);
net.Server.call(this, { allowHalfOpen: true });
if (requestListener) {
this.addListener('request', requestListener);
}
this.httpAllowHalfOpen = false;
this.addListener('connection', connectionListener);
this.addListener('clientError', function(err, conn) {
conn.destroy(err);
});
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
edited Oct 30 '15 at 3:11
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
answered Oct 30 '15 at 2:42
acjialirenacjialiren
916
916
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You're creating a webserver "instance" and passing it to sockec.io so it can use it for transport.
requireis just a function, if you return another function from the export, it can be called with arguments, and you can pass stuff to the middleware.– adeneo
Dec 15 '14 at 20:01
ExpressJS'
app.listen()is just for convenience for simple applications. It useshttp.Server(app), or ratherhttp.createServer(app);, itself.– Jonathan Lonowski
Dec 15 '14 at 20:36