CODEWITHSUNDEEP
node.js
user784637
user784637

Reputation: 16092

Difficulty understanding nodejs documentation

I'm really confused about this section

http://nodejs.org/api/http.html#http_http_createserver_requestlistener

The requestListener is a function which is automatically added to the 'request' event.

What does the term "added" specifically mean?

Also for here http://nodejs.org/api/http.html#http_event_request

What does the the code directly beneath mean function (request, response) { }? Does it mean that that function gets passed each time there is a request?

Upvotes: 0

Views: 184

Answers (2)

user568109
user568109

Reputation: 47993

If it is any help the statement

var app = http.createServer( function reqlistener(request, response){...} ).listen(1337);

where the function reqlistener is the requestListener argument, is equivalent to the following

var app = http.createServer().listen(1337);
app.on('request', function reqlistener(request, response){...} );

So it is just a shortcut for providing a listener for event request during server start itself. The event request is emitted for each request once when received by the server.

Upvotes: 1

Eric Smekens
Eric Smekens

Reputation: 1621

The requestListener is a lsitener that listens to the 'request' event. Each time a request event is emitted, the requestListener is executed. You pass a function.

That function you pass, should match:

function (request, response) { }

I believe there is an example at the main page of nodejs.org.

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(1337, '127.0.0.1');
console.log('Server running at http://127.0.0.1:1337/');

So each time a request-event is emitted, this function is 'called'.

function (req, res) {
      res.writeHead(200, {'Content-Type': 'text/plain'});
      res.end('Hello World\n');
    }

With req and res a parameters. (Request and response).

Upvotes: 2

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