what is blocking my node.js code? taking an argument from the command line

Question

I am trying to take the first command line argument as the port to run node on. The following code is not working in node.js:

try {

    if(process.argv[2] == undefined) {
        throw new Error("no port specified");
    }
    var port = process.argv[0];
    console.log(port);
}
catch (err) {
    console.log("Error give port number as the argument");
    return;
}
require('http').createServer(function handleRequest(req, res) {
    res.writeHead(200, {'content-type' : 'text/plain'});
    res.end('Hello World!');
}).listen(port);

It gives the following error:

$ node server.js 8080
node

events.js:72
        throw er; // Unhandled 'error' event
              ^
Error: listen EADDRINUSE
    at errnoException (net.js:884:11)
    at Server._listen2 (net.js:1003:19)
    at listen (net.js:1044:10)
    at Server.listen (net.js:1104:5)
    at Object.<anonymous> (/home/studiet/Documents/Aptana Studio 3 Workspace/nodef2b/server.js:19:4)
    at Module._compile (module.js:456:26)
    at Object.Module._extensions..js (module.js:474:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Function.Module.runMain (module.js:497:10)

I know that node.js is asyncronous, but in this case I thought nothing was waiting for anything. What is wrong? How can I make the system wait for whatever is taking too long here, and what is taking too long? Or, what else is wrong?

EDIT: line 19 in the code is where I .listen(port);

By the error Error: listen EADDRINUSE, I'm lead to believe there's already an application listening on that port. — Andrew Ty.
– Andrew Ty., Commented May 8, 2013 at 22:02

SLaks · Accepted Answer · 2013-05-08 22:01:00Z

5

EADDRINUSE stands for Error Address In Use.

Some other process is using port 80.

You need to find that process and terminate it with extreme prejudice.

EDIT: In this case, it means an invalid port number.
As you can see from your first line of output, port is "node", not 8080.
You need to set it to argv[2].

answered May 8, 2013 at 22:01

SLaks

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2 Comments

Piddien Over a year ago

I have tried 8080, 8081, 8082 and 80123. All give EADDRINUSE. What to do? Ubuntu. And never 80 I know that is not allowed

Piddien Over a year ago

Thanks! I see that I check for argv[2] but use argv[0].

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