discourse/app/assets/javascripts/discourse/components/onebox.js

/**
  A helper for looking up oneboxes and displaying them

  For now it only stores in a var, in future we can change it so it uses localStorage.

  @class Notification
  @extends Discourse.Model
  @namespace Discourse
  @module Discourse
**/
Discourse.Onebox = (function() {

  var cache, load, localCache, lookup, lookupCache;
  localCache = {};

  cache = function(url, contents) {
    localCache[url] = contents;
    return null;
  };

  lookupCache = function(url) {
    var cached;
    cached = localCache[url];
    if (cached && cached.then) {
      return null;
    } else {
      return cached;
    }
  };

  lookup = function(url, refresh, callback) {
    var cached;
    cached = localCache[url];
    if (refresh && cached && !cached.then) {
      cached = null;
    }
    if (cached) {
      if (cached.then) {
        cached.then(callback(lookupCache(url)));
      } else {
        callback(cached);
      }
      return false;
    } else {
      cache(url, jQuery.get("/onebox", {
        url: url,
        refresh: refresh
      }, function(html) {
        cache(url, html);
        return callback(html);
      }));
      return true;
    }
  };

  load = function(e, refresh) {
    var $elem, loading, url;
    if (!refresh) refresh = false;

    url = e.href;
    $elem = $(e);
    if ($elem.data('onebox-loaded')) {
      return;
    }
    loading = lookup(url, refresh, function(html) {
      $elem.removeClass('loading-onebox');
      $elem.data('onebox-loaded');
      if (!html) {
        return;
      }
      if (html.trim().length === 0) {
        return;
      }
      return $elem.replaceWith(html);
    });
    if (loading) {
      return $elem.addClass('loading-onebox');
    }
  };

  return {
    load: load,
    lookup: lookup,
    lookupCache: lookupCache
  };

})();