How to append new line character in node.js?

Question

I'm new to node.js and I'm trying to write a program that receives http requests and forwards the contents through a socket. At the other end of the socket is a paging system that needs messages terminated with a new line character. So far, it works fine, except there is an extra message sent with the contents: undefined.

When I print the contents of the pager message to the client's browser, there does not appear to be a new line. Am I doing this right?

sys = require("sys"),
http = require("http"),
url = require("url"),
path = require("path"),
net = require("net");

socket = new net.Socket();
socket.connect(4000, '192.168.0.105');

var httpServer = http.createServer(function(request, response) {
    var uri = String(url.parse(request.url).query);
    var message = uri.split("=");
    var page = 'FPG,101,0,3!A' + message[0] + '\n';
    response.writeHead(200, {"Content-Type":"text/html"});
    response.write('sending message: ' + page + " to pager");
    response.end();
    socket.write(page);
}).listen(8080);

sys.puts("Server running at http://localhost:8080/");

EDIT: I narrowed it down further. It turns out that if I do:

var page = 'FPG,101,0,3!A' + 'hello' + '\n';

It works okay. So the output of uri.split("=") must not be what I am expecting.

Wilburwilburn

If you watch the traffic with Wireshark, do you see trailing newlines? Do you need to send \r\n instead of just \n? – Byrn

No, I got this working in another application by just sending \n, so I know that's all I need. – Wilburwilburn

Answer 1

I figured out what the problem was. For some reason the browser was sending an additional request to the page right after my request. I just filtered for requests with a certain format and that fixed it.

Wilburwilburn

i dont think so. the solution to the issue is what @Duhl has mentioned above. – Bub

Answer 2

I'm sure the new line is there, but you aren't going to see it when you send your Content-Type as text/html. In HTML, \n is just other whitespace, and is treated as such. Use text/plain instead.

Duhl

Oh. Okay, well now I'm seeing it on the client's browser. There must be some other problem. Thanks. – Wilburwilburn

@ddor254 CSS controls how the whitespace is interpreted. Did you have a specific question? – Duhl

yeah , i mean where it is written in the HTML spec that CSS control the representation of the html? and why css is set as interpreter only when the content-type in text/html ? – Forrester

Answer 3

Since content type is 'text/html',we can happily use break statement.Just like this

res.write('hello'+'<br/>');
 res.write('nice to meet you');

You can try this code in node:

var http = require('http');

http.createServer(function (req, res) {

res.writeHead(200, { 'Content-Type': 'text/html' });
res.write('hello,this is saikiran'+'<br/>');
res.end('nice to meet you');

}).listen(process.env.PORT || 8080);
console.log('server running on port 8080');

Mistrot

Answer 4

As per content type of text/plain, you can also use \r to send a return input to the client's browser

Bernat

Answer 5

Consider using \\n instead of \n for new line.

Industrialism

in general it is true for text file. but here he ask for new line in html format for client browser – Lampley