boards/static/js/updates.js

var UPDATE_INTERVAL = 10000;

var ports = [];
var includePostBody = false;

function updateFavPosts() {
    var url = '/api/new_posts/';
    if (includePostBody) {
        url += '?include_posts';
    }

    var xhr = new XMLHttpRequest();

    xhr.onreadystatechange = function() {
        if (xhr.readyState == XMLHttpRequest.DONE) {
            if (xhr.status == 200 || xhr.status == 304) {
                var data = xhr.responseText;
                for (var i = 0; i < ports.length; i++) {
                    port = ports[i];
                    try {
                        port.postMessage(data);
                    } catch (error) {
                        // Assume the port was closed with the tab
                        var index = ports.indexOf(port);
                        ports.splice(index, 1);
                    }
                }
            }
        }
    }

    xhr.open('GET', url);
    xhr.send(null);
}

onconnect = function(e) {
    var port = e.ports[0];
    port.start();

    port.onmessage = function(e) {
        // FIXME For now we include body even if a panel was opened once
        if (e.data.includePostBody) {
            includePostBody = true;
        }
        updateFavPosts();
    }

    ports.push(port);
}

setInterval(function() {
    updateFavPosts();
}, UPDATE_INTERVAL);