Using Alchemy API Synchronously

Question

I am attempting to write a pure function to use the Alchemy API with the watson-developer-cloud npm package, but I cannot figure out how to execute its calls synchronously. Is there an alternative method or package whereby I could receive its results synchronously? Blocking while the I/O is occurring is absolutely fine.

Answer 1

You can not do synchronous calls with the watson-developer-cloud npm module. What you can do is use Promises and mimic the synchronous model.

The example below shows how to call the AlchemyVision recognizeFacesmethod using promises:

var watson = require('watson-developer-cloud');
var Q = require('q');

var alchemy_vision = watson.alchemy_vision({
  api_key: '<api_key>'
});

// Creates a promise-returning function from a Node.js-style function
var recognizeFaces = Q.denodeify(alchemy_vision.recognizeFaces.bind(alchemy_vision));

var params = {
  url: 'http://si.wsj.net/public/resources/images/BN-BY925_mag041_OZ_20140318165119.jpg'
};

recognizeFaces(params).then(function (keywords) {
  console.log(JSON.stringify(keywords, null, 2));
}).catch(function (err) {
    console.log('error:', err);
});