silvrgit/lib/btc.js

 let http = require('http');
 let btcCache = {};
 exports.doBTC = function(req, res) {
  console.log('Bitcoin request');
  function btcQuery(callback, r) {
          var req = r;
          var options = {
              host: 'api.coindesk.com',
                //  port: 80,
              path: '/v1/bpi/currentprice.json',
                // method: 'GET',
              headers: {
                    /*   'Content-Type': 'application/json',
                     'Content-Length': Buffer.byteLength(data)*/

                }
            };
          try {
  http.request(options).on('response', function(response) {
              var data = '';
              response.on('data', function(chunk) {
                  data += chunk;
                });
              response.on('end', function() {
                  callback(JSON.parse(data), r);
                });
              response.on('error', function(e) {
                console.error(e);
              });
            }).end();
} catch (e) {
  console.error(e);
}
        }

  let now = new Date();
  if (now - GLOBAL.lastcheck > (59000 )) {
          btcQuery(function(a) {
               // console.log(a);
              console.log('Got btc data.');
              btcCache = a;
              GLOBAL.lastcheck = now;
              res.setHeader('Content-Type', 'application/json');
              res.end(JSON.stringify(btcCache));
            }, res);
        }        else {
          console.log('Using cache');
          res.setHeader('Content-Type', 'application/json');
          res.end(JSON.stringify(btcCache));
        }
};