How to append new line character in node.js?

David picture David · May 4, 2012 · Viewed 27.6k times · Source

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.

Answer

Brad picture Brad · May 4, 2012

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.