artsy-xapp/index.js

Tiny lib to fetch and refresh an xapp token from Artsy's API.

var Emitter = require('events').EventEmitter,
  request = require('superagent');

module.exports = new Emitter();

module.exports.init = function (options, callback) {

  // Do a solid and just callback for test env
  if (process.env.NODE_ENV == 'test') return callback();

  // Setup defaults
  if(typeof options == 'function') {
    callback = options;
    var options = {};
  }
  if (!options.url) options.url = process.env.ARTSY_URL;
  if (!options.id) options.id = process.env.ARTSY_ID;
  if (!options.secret) options.secret = process.env.ARTSY_SECRET;

  // Fetch the xapp token, cache, and refresh
  fetchAndCacheToken(options)(callback);
}

var fetchAndCacheToken = function (options){
  return function(callback) {

    // Get the token
    request
      .get(options.url + '/api/v1/xapp_token')
      .query({ client_id: options.id, client_secret: options.secret })
      .end(function(err, res) {
        if (err) {
          module.exports.emit('error', err);
          if (callback) callback(err);
          return
        }
        module.exports.token = res.body.xapp_token;
        if (callback) callback(null, module.exports.token);

        // Recurse this function to refresh the token it before it expires
        var expiresAt = new Date(res.body.expires_in).getTime();
        setTimeout(fetchAndCacheToken(options), (expiresAt - 1000) - Date.now());
      });
    }
}