how to read file using fs in node app? - javascript

I'm tring to read this file in nodejs using fs module.
I'm getting the response twice. let me know what am i doing wrong. Here's my code.
var http = require("http");
var fs = require("fs");
http.createServer(function(req, res) {
fs.readFile('sample.txt', function(err, sampleData) {
console.log(String(sampleData));
//res.end();
});
console.log("The end");
// res.writeHead(200);
res.end();
}).listen(2000);
After hitting the port in browser. I'm getting the response twice in my terminal. Here's the output.
The end
this is sample text for the testing.
The end
this is sample text for the testing.

You are most likely getting it twice because you are accessing http://localhost:2000/ from the browser.
When doing so there are actually two requests being made. Your actual request and the favicon :) both of which are handled by your server.
Have a look into Chrome debugger -> Network

Two log messages will appear: one for / and one for /favicon.ico
You can verify this by adding console.log(req.url);
To avoid this:
var http = require("http");
var fs = require("fs");
http.createServer(function(req, res){
if(req.url === '/'){ // or if(req.url != '/faicon.ico'){
fs.readFile('sample.txt', function(err , sampleData){
console.log(String(sampleData));
res.end();
});
console.log("The end");
}
// res.writeHead(200);
}).listen(2000);

A request is made to favicon.io automatically.
To avoid automatic request to favicon, you can do the following
http.createServer(function(req, res){
if(req.url != '/favicon.ico'){
fs.readFile('sample.txt', function(err , sampleData){
console.log(String(sampleData));
res.end();
});
console.log("The end");
}
}).listen(2000);
O/p =>
The end.
this is sample text for the testing.

You may pipe the file to the client:
fs.createReadStream('sample.txt').pipe(res);

Related

Can't serve javascript file with html - node.js

I have a webpage with an HTML, CSS, and JS file. It also has one image. I am able to get all of them to function and serve onto the client side, except for the javascript portion. It is most likely a silly syntax thing but I have not been able to solve it.
Here is the code for my .js serving:
else if(req.url === '/index.js'){
console.log("SERVING JS")
res.writeHead(200, {'Content-Type': 'application/json'})
var javaContents = fs.readFileSync('./public/index.js', {encoding: 'UTF8'});
res.write(javaContents);
res.end();
}
^^^ Which is inside my requestHandler function:
function requestHandler(req, res){
}
Before this, I also have:
var http = require('http'), fs = require('fs');
var fs = require('fs');
And I declare my server variable last:
var server = http.createServer(requestHandler);
server.listen(9934, function(){
console.log("== Server is listening on port 9934");
});
I could post all my code but I think that is not necessary. Thank you!

Loading html page on nodeJS won't load until keyboard interrupt

I am new to nodeJS. I am trying to load an index.html page onto my 8080 port and have this:
var http = require('http');
var fs = require('fs');
var PORT = 8080;
function home(req, res) {
if(req.url == '/'){
fs.readFile('index.html', function read (err, data) {
res.writeHead(200, {'Content-type' : 'text/html'});
res.write(data);
res.end();
});
}
};
var server = http.createServer(function (req, res) {
home(req, res);
});
server.listen(PORT);
I have 3 files in the same directory: index.html, style.css, server.js. I start up the server and the page will not load until after I hit cntrl + c. Why is this?
You have written the data to the response, but you have not finished the response. Put res.end(); after your res.write function.
Without this, the browser keeps waiting for more data from the server. When you shut down the server with Ctrl-C, the server closes the connection, and the browser renders what it received.
If you are new to Node, I would recommend looking into something like Express, which handles a lot of important things like routing (what URLs go to which pages) for you and will save you a lot more if statements in the future.

error function is not defined for res node

I use the following code and when I run the program which is run this function I got error res is not defiend(TypeError: undefined is not a function),what It can be ?I have it in the function params???
http.createServer(function (req, res) {
res.redirect("http://localhost:3002");
}).listen(9006);
https://github.com/nodejitsu/node-http-proxy
There I use the
Setup a stand-alone proxy server with custom server logic
undefined is not a function means redirect is not a function (or method) of res. I'll bet you if you do console.log(res), you won't get an error, which means that, yes, res is defined, but redirect is not. It is an ExpressJS method, so I assume you haven't require'ed Express is your app, if you were planning to use it.
If you want to redirect without Express, one option is to set a different location header and response code (from here):
response.writeHead(302, {
'Location': 'your/404/path.html'
//add other headers here...
});
response.end();
From Wikipedia:
The HTTP response status code 302 Found is a common way of performing
URL redirection.
Edit
According to the library you've provided:
You may send a response page using what #Josh wrote or you may also handle the 404 page at the same time with the following code:
var http = require('http'),
fs = require('fs'),
util = require('util'),
url = require('url');
var server = http.createServer(function(req, res) {
if(url.parse(req.url).pathname == '/') {
res.writeHead(200, {'content-type': 'text/html'});
var rs = fs.createReadStream('index.html');
util.pump(rs, res);
} else {
res.writeHead(404, {'content-type': 'text/html'});
var rs = fs.createReadStream('404.html');
util.pump(rs, res);
}
});
server.listen(8080);
NodeJs don't have any redirect function use following code for redirect
res.writeHead(302, {
'Location': 'http://localhost:3002'
//add other headers here...
});
response.end();
Note TypeError: undefined is not a function means that function you trying to access is not defined.

NodeJS - "This type of response MUST not have a body..."

I've recently ran into a very interesting problem while writing a web app with node.js.
Essentially, all I am doing is serving the index.html page to the client.
Here is the code:
var http = require('http');
var url = require('url');
var fs = require('fs');
var util = require('util');
var server = http.createServer(function(req, res){
var path = url.parse(req.url).pathname;
if(path == '/'){
console.log("LOADING INDEX...");
openIndex(req, res);
console.log("LOADING COMPLETE.")
} else {
res.write("Something went wrong...");
res.end();
}
}
);
var openIndex = function(req, res){
fs.readFile('./index.html', function(error, content){
if(error){
res.writeHead(500);
res.end();
}
else{
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(content, 'utf-8');
}
});
}
I've put some debugging statements just before and after the index.html page loads: "LOADING INDEX..." and "LOADING COMPLETE".
Now, I have shared the link to my server with my Facebook friends so they can see my app. Most of the time, everything works as it should, but once in a while I get this error:
LOADING INDEX...
This type of response MUST NOT have a body. Ignoring data passed to end().
and just now I've also gotten:
LOADING INDEX...
This type of response MUST NOT have a body. Ignoring write() calls.
The process never raches the "LOADING COMPLETE" statement.
I've tried to reproduce this countless times (accessing my app on different machines, browsers, devices, OS-versions) but every time it works as it should.
I've looked around for other people having this problem, and it seems that somehow, a body is getting into a GET response? I'm not entirely sure what this means or how to fix my code to prevent that from happening. Also, I'm not sure what the clients that produce this error see? Do they get to see my app? (i.e. are these just warnings and as far as they are concerned everything is fine?)
Any help with this will be greatly appreciated.
Xaan
If you're just using a static index.html, why not use express.static to serve it automatically?
app.use("/index.html", express.static(__dirname + '/index.html'));
This would cause expressjs to automatically handle HEAD requests, which should solve your problem.

Setting a document root to your Node.js http server?

I just setup a basic node.js server with socket.io on my local machine. Is there a way to set a document root so that you can include other files. Ie. Below I have a DIV with a a background image. The path the image is relative to the location of the server, however this is not working. Any ideas? Thanks!
var http = require('http'),
io = require('socket.io'), // for npm, otherwise use require('./path/to/socket.io')
server = http.createServer(function(req, res){
// your normal server code
res.writeHead(200, {'Content-Type': 'text/html'});
res.end('<div style="background-image:url(img/carbon_fibre.gif);"><h1>Hello world</h1></div>');
});
server.listen(8080);
// socket.io
var socket = io.listen(server);
Use Express or Connect. Examples: https://github.com/spadin/simple-express-static-server, http://senchalabs.github.com/connect/middleware-static.html
For the background-image style, browser will create a entirely new HTTP Request to your server with path *img/carbon_fibre.gif*, and this request will certainly hit your anonymous function, but your response function only write back a div with ContentType: text/html regardless the req.pathname so that the image cannot be properly displayed.
You may add some code to your function like:
var http = require('http'),
io = require('socket.io'),
fs = require('fs'),
server = http.createServer(function(req, res){
// find static image file
if (/\.gif$/.test(req.pathname)) {
fs.read(req.pathname, function(err, data) {
res.writeHead(200, { 'Content-Type': 'image/gif' });
res.end(data);
});
}
else {
// write your div
}
});
server.listen(8080);
I'm not very familiar with nodejs, so the code above only demonstrates a logic but not the actual runnable code block.

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