jpeginator.js

// The JPEGINATOR
// OpenWhisk action to convert images to JPEG
//
// Author: Frederico Munoz <frederico.munoz@pt.ibm.com>
// Date: APR 2017
// License: Eclipse Public License 1.0

var fs = require('fs');
var gm = require('gm').subClass({imageMagick: true});

exports.main = function (params) {

    // We must receive the image as base64 and identified by the image
    // keyword
    var b64string = params.image;
    var buf = Buffer.from(b64string, 'base64')

    // Using promises since gm is async
    return new Promise(function(resolve, reject) {
        gm(buf).toBuffer('JPEG', function (err, buffer) {
            if (err)
            {
                console.log("Error");
                return {result: "error"};
            } else {
                console.log("Success");
                resolve({image: buffer.toString('base64')});
            }
        });
    });
}