Using promises to GET and process data

Question

I'm working on a Meteor application which integrates a user's contacts from external sources (Google in the case of this example). I'm currently writing the server side code to retrieve this data and send it to the client.

I figured using promises to do this made sense due to the asynchronous manner of requests. So I have getContacts which sends the request to the Google API, and processContacts which processes and formats the response data:

getContacts = function (accessToken) {
  return new Promise(function (resolve) {
    httpRequest.get({
      url: 'https://www.google.com/m8/feeds/contacts/default/full?alt=json',
      auth: {
        'bearer': accessToken
      },
      headers: {
        'GData-Version': 3.0
      },
    }, function (err, res, body) {
      resolve(body);
    });
  });
}

processContacts = function(googleContacts) {
  return new Promise(function(resolve) {
    const contacts    = JSON.parse(googleContacts).feed.entry;
    const allContacts = [];
    const groupedContacts = { conflicts: [], new: [] };
    ...    
    ...
    resolve(groupedContacts);
  });
}

I have a Meteor method google.contacts.import which is called synchronously from the client, and because all of this is asynchronous I'm using a future to force the client to wait for the call to finish:

Meteor.methods({
  'google.integration.import'(orgId) {
    check(orgId, String);

    const user = Users.getOne(Meteor.userId());
    let fut = new Future();

    getContacts(user.services.google.accessToken)
    .then(processContacts)
    .then(function(contacts){
      fut.return(contacts);
    })
    .catch(function(err){
      console.log('error! :' + err);
    });

    return fut.wait();
  },
})

This all works fine, but it seems...messy or somewhat convoluted. I'm relatively new to Javascript and ES6 in particular so I feel I could definitely improve this. Am I correct to be using promises here? I guess they probably aren't necessary in the case of processContacts. I also realize this is lacking in terms of error checking/reporting.

Any help or guidance is appreciated!

Answer 1

I think the preferred way to handle async on the server in Meteor is to use fiber aware async functions, e.g. use the http Meteor package which gives you fiber aware "sync" style calls on the server (you write it like a sync call but it does not block the thread) and standard async callback signature on the client.

Also, I am not sure about using futures on the client, is there even a fibers environment running on the client? Instead, I think you just pass a standard callback to Meteor.call to handle the results of the method.

Answer 2

I think you are fine to use promises here, although I agree that a promise is not necessarily required for processContacts. Not sure if this was helpful.

EDIT: Because of the nature of your program, processContacts is going to be asynchronous no matter what, so using a promise is not a bad idea.