Question

i’m trying to write a simple app with node.js to pull some json from twitter..

json loads ok the first time, however, my ‘tweets’ event isnt getting triggered correctly..

anyone see where I’m going wrong? any advice hugely appreciated !

var twitterClient = http.createClient(80, 'api.twitter.com');
var tweetEmitter = new events.EventEmitter();
var request = twitterClient.request("GET", "/1/statuses/public_timeline.json", {"host": "api.twitter.com"});

function getTweats() {

    request.addListener("response", function (response) {
        var body = "";

        response.addListener("data", function (data) {
            body += data;
        });

        response.addListener("end", function (end) {
            var tweets = JSON.parse(body);
            if (tweets.length > 0) {
                tweetEmitter.emit("tweets", tweets);
                console.log(tweets, 'tweets loaded');
            }
        });
    });

    request.end();
}

setInterval(getTweats(), 1000);


http.createServer(function (request, response) {
    var uri = url.parse(request.url).pathname;
    console.log(uri);
    if (uri === '/stream') {
        var cb = function (tweets) {
            console.log('tweet'); // never happens!
            response.writeHead(200, {"Content-Type": "text/plain"});
            response.write(JSON.stringify(tweets));
            response.end();
            clearTimeout(timeout);
        };
        tweetEmitter.addListener("tweets", cb);

        // timeout to kill requests that take longer than 10 secs
        var timeout = setTimeout(function () {
            response.writeHead(200, {"Content-Type": "text/plain"});
            response.write(JSON.stringify([]));
            response.end();
            tweetEmitter.removeListener("tweets", cb);
        }, 10000);

    } else {
        loadStaticFile(uri, response);
    }

}).listen(port);

console.log("Server running at http://localhost:" + port + "/");

see full file @ https://gist.github.com/770810

Answer 1

You have two problems here:

1. httpClient.request is just that, a one time request.
2. You’re not passing the function getTweats to the interval, but its return value:
   setInterval(getTweats() */ <-- parenthesis execute the function */, 1000);

In order to fix it, create a new request for each call of getTweats:

function getTweats() {
     // There's no need for request being global, just make it local to getTweats
     var request = twitterClient.request("GET", "/1/statuses/public_timeline.json", {"host": "api.twitter.com"});

And pass the function correctly to setTimeout:

setInterval(getTweats, 1000);

PS: Thx for the gist! Took me like 15 seconds to figure it out from there, always great when people post more than just 5 lines of out of context code 🙂