Meteor vs. the Twitter API via wrapAsync and Twit

meteor-wrapasync.md

Twit and other Node libraries don't always quite drop into Meteor's reactive architecture right out of the box. Luckily Meteor makes adapting them super-duper easy with wrapAsync. It was so easy that I naturally tried all the more difficult ways first! Since I didn't find a nice gist or StackOverflow example, please enjoy this one.

In the template -

{{#with pos}}
  {{#if ready}}
    {{> singlePosition data }}
  {{/if}}
{{/with}}

In client.js -

Template.home.helpers({
  pos: function () {
    var ready = Meteor.subscribe('positions').ready();
    apos = Positions.findOne({}, {sort: {'submittedOn': -1}});

    if (apos && !apos.targetImg) {
      console.log('calling targetImg for ' + apos.target);
      var targetImg = Meteor.call("getTwitImg", apos.target, function(error, results) {
        if (results)
          Positions.update(apos._id, {$set: {'targetImg': results}});  
      });
    }

    return {
      data: apos,
      ready: ready
    };
  },
})

In server.js -

var T = new TwitMaker({
    consumer_key:         '...'
  , consumer_secret:      '...'
  , access_token:         '...'
  , access_token_secret:  '...'
})

var wrapGet = Meteor.wrapAsync(T.get, T);

Meteor.methods({

  getTwitImg: function(target) {
    data = wrapGet('users/show', {screen_name: target});
    if (data) {
      img_url = data['profile_image_url'];
      US.update({twitter: target}, {$set: {'targetImg': img_url}});
      return img_url;
    }
  }
  
});

Way easier than manually using bindEnvironment or Futures!

How do you deal with errors thrown in your wrapGet function? How do you return those as the error parameter in the callback? I tried enclosing the function in a try/catch block, which gives me a nice error message, but then how do you pass that on to the callback?