What is the difference between the request in this line of code:
http.createServer(function(request,response){. . .}
and request in
http.request()
Are both requests done to the server?
I am new to node.js and I am sorry if I sound dumb!
How does http.request() work?
In http.request() we fetch data from another site but in order to fetch data from another site we first need to go to our site and then make a request? Explain it with a simple real-life example!
http.request() makes a request to another HTTP server. Suppose for some reason I wanted to go download Stack Overflow's home page...
http.request('https://stackoverflow.com/', (res) => {
// ...
});
http.createServer()... it creates an HTTP server. That is, it binds your application to a socket to listen on. When a new connection is made from somewhere or something else, it handles the underlying HTTP protocol of that request and asks your application to deal with it by way of a callback. From the Node.js documentation:
http.createServer((req, res) => {
res.writeHead(200, { 'Content-Type': 'text/plain' });
res.end('okay');
});
These two methods have absolutely nothing to do with each other. http.request() is for making a request to an HTTP server. http.createServer() is for creating your own HTTP server. Don't get confused by the callbacks.
Based on the source code of nodejs (extract below), createServer is just a helper method to instantiate a Server.
Extract from line 1674 of http.js.
exports.Server = Server;
exports.createServer = function(requestListener) {
return new Server(requestListener);
};
The http.request() API is for when you want your server code to act as a client and request content from another site and has GET, POST, PUT, DELETE methods.
I am executing following simple node js code
var http = require('http');
http.createServer(function(req, res) {
res.writeHead(200, {'Content-Type':'text/plain'});
res.end('Hello Node JS');
console.log('printing the message');
}).listen(8080);
After executing the command node sample.js and
hitting the url on browser http://localhost:8080/
I am getting the console log statement twice on the command prompt as printing the message
Any Suggestions
EDIT:
Interestingly After checking on other browsers i.e. Firefox, IE no favicon.ico request is made on network tab and console message is printed only once.
As I understood, using express module is better option to handle requests in a typical web application
check the Network area of your browser's developer console to find out what requests are being made. I imagine you will see two:
GET /
GET /favicon.ico
your HTTP server is coded to respond to all requests by printing to console; so if you see two requests, you get two console messages.
I am learning Node.js and I have created this simple http server.
var http = require('http');
var server = http.createServer(function(req,res){
console.log('request accepted');
res.end();
});
server.listen(3000,function(){
console.log("Server listening on port #3000");
});
It is working fine but when I visit http://localhost:3000/ the console logs request accepted thing twice. In short, if I'm understanding correctly, the request is received twice.
Is it a correct behavior or am I doing something wrong here?
Your browser makes two HTTP requests. One for the page at / and the other for /favicon.ico.
You can prove this by inspecting req.url.
you can try to put your favicon as a data64 string so you will save that request, anyway some browsers could make that request anyway.
I am using Gulp to develop an Angular application generated by Yeoman's gulp-angular generator. I have configured it to proxy requests to /api to another port, the port my API is listening on. That port is actually forwarded via an SSH tunnel to an external server.
Here is the config generated by Yeoman that I have edited for my own API:
gulp/server.js
'use strict';
var gulp = require('gulp');
var browserSync = require('browser-sync');
var httpProxy = require('http-proxy');
/* This configuration allow you to configure browser sync to proxy your backend */
var proxyTarget = 'http://localhost:3434/api'; // The location of your backend
var proxyApiPrefix = 'api'; // The element in the URL which differentiate between API request and static file request
var proxy = httpProxy.createProxyServer({
target: proxyTarget
});
function proxyMiddleware(req, res, next) {
if (req.url.indexOf(proxyApiPrefix) !== -1) {
proxy.web(req, res);
} else {
next();
}
// ...rest of config truncated
stdout
[BS] Watching files...
/Users/jason/dev/web/node_modules/http-proxy/lib/http-proxy/index.js:114
throw err;
^
Error: Parse Error
at Socket.socketOnData (http.js:1583:20)
at TCP.onread (net.js:527:27)
I get the above error when my application attempts to hit a particular API url which sends back a response of 204, no content.
url structure: POST /api/resource/delete
(API doesn't support actual DELETE http method so we POST to this endpoint)
Response: 204 No Content
The API is also in development and is being served via the built in PHP web server. What the server is telling us is that the client (aka Node in this case because it is the proxy) is hanging up before PHP can send the response.
I thought perhaps it was just choking on the fact that there was no content. So, we created a second endpoint that also returned 204 No Content and it seemed to work fine. But, to be fair, this issue appears to be intermittent - it works sometimes and sometimes it does not. It's very confusing.
As far as we can tell, it only happens on this delete URL, however. I am pretty new to Node and am having a very hard time figuring out what the issue is or where to look. Does anyone have any clues or has anyone seen this before?
It turns out that the developer of the API was sending me content along with his 204 when he shouldn't have been - some debug code left in. The HTTP parser that node-proxy uses was then reading that content from the buffer at the beginning of the subsequent request and then throwing an error because it wasn't seeing a properly formed HTTP request - since the first thing in the buffer was a PHP var_dump.
As it happens, my front end app did the delete call and then refreshes another object via the GET request. They happen so fast that it seemed like the DELETE call killed the gulp server, when it was actually the GET command afterwards.
The http-proxy module for node explicitly does not do error handling, leaving the onus on the end user. If you don't handle an error, it bubbles up into an uncaught exception and will cause the application to close, as I was seeing.
So, the fix was simply:
gulp/server.js
var proxy = httpProxy.createProxyServer({
target: proxyTarget
}).on('error', function(e) {
console.log(JSON.stringify(e, null, ' '))
});
The console will now log all proxy errors, but the process won't die and subsequent requests will continue to be served as expected.
For the error in question, the console output is:
{
"bytesParsed": 191,
"code": "HPE_INVALID_CONSTANT"
}
Additionally, we've fixed the API to honor its 204 and actually, you know, not send content.
To learn node.js I'm creating a small app that get some rss feeds stored in mongoDB, process them and create a single feed (ordered by date) from these ones.
It parses a list of ~50 rss feeds, with ~1000 blog items, so it's quite long to parse the whole, so I put the following req.connection.setTimeout(60*1000); to get a long enough time out to fetch and parse all the feeds.
Everything runs quite fine, but the request is called twice. (I checked with wireshark, I don't think it's about favicon here).
I really don't get it.
You can test yourself here : http://mighty-springs-9162.herokuapp.com/feed/mde/20 (it should create a rss feed with the last 20 articles about "mde").
The code is here: https://github.com/xseignard/rss-unify
And if we focus on the interesting bits :
I have a route defined like this : app.get('/feed/:name/:size?', topics.getFeed);
And the topics.getFeed is like this :
function getFeed(req, res) {
// 1 minute timeout to get enough time for the request to be processed
req.connection.setTimeout(60*1000);
var name = req.params.name;
var callback = function(err, topic) {
// if the topic has been found
if (topic) {
// aggregate the corresponding feeds
rssAggregator.aggregate(topic, function(err, rssFeed) {
if (err) {
res.status(500).send({error: 'Error while creating feed'});
}
else {
res.send(rssFeed);
}
},
req);
}
else {
res.status(404).send({error: 'Topic not found'});
}};
// look for the topic in the db
findTopicByName(name, callback);
}
So nothing fancy, but still, this getFeed function is called twice.
What's wrong there? Any idea?
This annoyed me for a long time. It's most likely the Firebug extension which is sending a duplicate of each GET request in the background. Try turning off Firebug to make sure that's not the issue.
I faced the same issue while using Google Cloud Functions Framework (which uses express to handle requests) on my local machine. Each fetch request (in browser console and within web page) made resulted in two requests to the server. The issue was related to CORS (because I was using different ports), Chrome made a OPTIONS method call before the actual call. Since OPTIONS method was not necessary in my code, I used an if-statement to return an empty response.
if(req.method == "OPTIONS"){
res.set('Access-Control-Allow-Origin', '*');
res.set('Access-Control-Allow-Headers', 'Content-Type');
res.status(204).send('');
}
Spent nearly 3hrs banging my head. Thanks to user105279's answer for hinting this.
If you have favicon on your site, remove it and try again. If your problem resolved, refactor your favicon url
I'm doing more or less the same thing now, and noticed the same thing.
I'm testing my server by entering the api address in chrome like this:
http://127.0.0.1:1337/links/1
my Node.js server is then responding with a json object depending on the id.
I set up a console log in the get method and noticed that when I change the id in the address bar of chrome it sends a request (before hitting enter to actually send the request) and the server accepts another request after I actually hit enter. This happens with and without having the chrome dev console open.
IE 11 doesn't seem to work in the same way but I don't have Firefox installed right now.
Hope that helps someone even if this was a kind of old thread :)
/J
I am to fix with listen.setTimeout and axios.defaults.timeout = 36000000
Node js
var timeout = require('connect-timeout'); //express v4
//in cors putting options response code for 200 and pre flight to false
app.use(cors({ preflightContinue: false, optionsSuccessStatus: 200 }));
//to put this middleaware in final of middleawares
app.use(timeout(36000000)); //10min
app.use((req, res, next) => {
if (!req.timedout) next();
});
var listen = app.listen(3333, () => console.log('running'));
listen.setTimeout(36000000); //10min
React
import axios from 'axios';
axios.defaults.timeout = 36000000;//10min
After of 2 days trying
you might have to increase the timeout even more. I haven't seen the express source but it just sounds on timeout, it retries.
Ensure you give res.send(); The axios call expects a value from the server and hence sends back a call request after 120 seconds.
I had the same issue doing this with Express 4. I believe it has to do with how it resolves request params. The solution is to ensure your params are resolved by for example checking them in an if block:
app.get('/:conversation', (req, res) => {
let url = req.params.conversation;
//Only handle request when params have resolved
if (url) {
res.redirect(301, 'http://'+ url + '.com')
}
})
In my case, my Axios POST requests were received twice by Express, the first one without body, the second one with the correct payload. The same request sent from Postman only received once correctly. It turned out that Express was run on a different port so my requests were cross origin. This caused Chrome to sent a preflight OPTION method request to the same url (the POST url) and my app.all routing in Express processed that one too.
app.all('/api/:cmd', require('./api.js'));
Separating POST from OPTIONS solved the issue:
app.post('/api/:cmd', require('./api.js'));
app.options('/', (req, res) => res.send());
I met the same problem. Then I tried to add return, it didn't work. But it works when I add return res.redirect('/path');
I had the same problem. Then I opened the Chrome dev tools and found out that the favicon.ico was requested from my Express.js application. I needed to fix the way how I registered the middleware.
Screenshot of Chrome dev tools
I also had double requests. In my case it was the forwarding from http to https protocol. You can check if that's the case by looking comparing
req.headers['x-forwarded-proto']
It will either be 'http' or 'https'.
I could fix my issue simply by adjusting the order in which my middlewares trigger.