Vulcan/packages/nova-embedly/lib/server/get_embedly_data.js

getEmbedlyData = function (url) {
  var data = {};
  var extractBase = 'http://api.embed.ly/1/extract';
  var embedlyKey = Telescope.settings.get('embedlyKey');
  var thumbnailWidth = Telescope.settings.get('thumbnailWidth', 200);
  var thumbnailHeight = Telescope.settings.get('thumbnailHeight', 125);

  if(!embedlyKey) {
    // fail silently to still let the post be submitted as usual
    console.log("Couldn't find an Embedly API key! Please add it to your Telescope settings or remove the Embedly module.");
    return null;
  }

  try {

    var result = Meteor.http.get(extractBase, {
      params: {
        key: embedlyKey,
        url: url,
        image_width: thumbnailWidth,
        image_height: thumbnailHeight,
        image_method: 'crop'
      }
    });

    // console.log(result)

    if (!!result.data.images && !!result.data.images.length) // there may not always be an image
      result.data.thumbnailUrl = result.data.images[0].url.replace("http:", ""); // add thumbnailUrl as its own property and remove "http"

    if (result.data.authors && result.data.authors.length > 0) {
      result.data.sourceName = result.data.authors[0].name;
      result.data.sourceUrl = result.data.authors[0].url;
    }

    var embedlyData = _.pick(result.data, 'title', 'media', 'description', 'thumbnailUrl', 'sourceName', 'sourceUrl');

    return embedlyData;

  } catch (error) {
    console.log(error)
    // the first 13 characters of the Embedly errors are "failed [400] ", so remove them and parse the rest
    var errorObject = JSON.parse(error.message.substring(13));
    throw new Meteor.Error(errorObject.error_code, errorObject.error_message);
    return null;
  }
}

// For security reason, we make the media property non-modifiable by the client and
// we use a separate server-side API call to set it (and the thumbnail object if it hasn't already been set)

// Async variant that directly modifies the post object with update()
function addMediaAfterSubmit (post) {
  var set = {};
  if(post.url){
    var data = getEmbedlyData(post.url);
    if (!!data) {
      // only add a thumbnailUrl if there isn't one already
      if (!post.thumbnailUrl && !!data.thumbnailUrl) {
        set.thumbnailUrl = data.thumbnailUrl;
      }
      // add media if necessary
      if (!!data.media.html) {
        set.media = data.media;
      }
      // add source name & url if they exist
      if (!!data.sourceName && !!data.sourceUrl) {
        set.sourceName = data.sourceName;
        set.sourceUrl = data.sourceUrl;
      }
    }
    // make sure set object is not empty (Embedly call could have failed)
    if(!_.isEmpty(set)) {
      Posts.update(post._id, {$set: set});
    }
  }
}
Telescope.callbacks.add("posts.new.async", addMediaAfterSubmit);

function updateMediaOnEdit (modifier, post) {
  var newUrl = modifier.$set.url;
  if(newUrl && newUrl !== post.url){
    var data = getEmbedlyData(newUrl);
    if(!!data) {
      if (!!data.media.html) {
        modifier.$set.media = data.media;
      }

      // add source name & url if they exist
      if (!!data.sourceName && !!data.sourceUrl) {
        modifier.$set.sourceName = data.sourceName;
        modifier.$set.sourceUrl = data.sourceUrl;
      }
    }
  }
  return modifier;
}
Telescope.callbacks.add("posts.edit.sync", updateMediaOnEdit);

var regenerateThumbnail = function (post) {
  delete post.thumbnailUrl;
  delete post.media;
  delete post.sourceName;
  delete post.sourceUrl;
  addMediaAfterSubmit(post);
};

Meteor.methods({
  testGetEmbedlyData: function (url) {
    check(url, String);
    console.log(getEmbedlyData(url));
  },
  getEmbedlyData: function (url) {
    check(url, String);
    return getEmbedlyData(url);
  },
  embedlyKeyExists: function () {
    return !!Telescope.settings.get('embedlyKey');
  },
  generateThumbnail: function (post) {
    check(post, Posts.simpleSchema());
    if (Users.can.edit(Meteor.user(), post)) {
      regenerateThumbnail(post);
    }
  },
  generateThumbnails: function (limit = 20, mode = "generate") {
    // mode = "generate" : generate thumbnails only for all posts that don't have one
    // mode = "all" : regenerate thumbnais for all posts
      
    if (Users.is.admin(Meteor.user())) {
      
      console.log("// Generating thumbnails…")
      
      const selector = {url: {$exists: true}};
      if (mode === "generate") {
        selector.thumbnailUrl = {$exists: false};
      }

      const posts = Posts.find(selector, {limit: limit, sort: {postedAt: -1}});

      posts.forEach((post, index) => {
        Meteor.setTimeout(function () {
          console.log(`// ${index}. fetching thumbnail for “${post.title}” (_id: ${post._id})`);
          try {
            regenerateThumbnail(post);
          } catch (error) {
            console.log(error);
          }
        }, index * 1000);
      });
    }
  }
});