server side paypal class

server-meteor-paypal.js

var paypal = new PaypalSDK();

Meteor.startup(function ObservePaypalSettings() {
/*
var paypalSchema = new SimpleSchema({
  enable: {
    type: Boolean,
    defaultValue: false,
  },
  isSandBox: {
    type: Boolean,
    label: 'Use sandbox for paypal (demo mode)',
    defaultValue: true,
  },
  clientId: {
    type: String,
    min: 50,
    optional: true,
  },
  clientSecret: {
    type: String,
    min: 50,
    optional: true,
  }
});

var schema = new SimpleSchema({
  // ...
  paypal: {
    type: paypalSchema,
    label: 'Paypal config'
  }
});
*/
  var query = Settings.find({}, {limit: 1, fields: {paypal: 1}});

  query.observeChanges({
    added:   observeSettings,
    changed: observeSettings
  });

  function observeSettings(id, fields) {
    if (fields.paypal) {
      paypal.config(fields.paypal);
    }
  }

});

/*
 * Low level paypal REST api
 */
function PaypalSDK() {
  this._token = this._url = this._config = undefined;
}

_.extend(PaypalSDK.prototype, {
  // congig our sdk
  config: function(config) {
    if (config) {
      this._config = config;
      this._url = config.isSandBox ? 'https://api.sandbox.paypal.com'
                                   : 'https://api.paypal.com';
    } else {
      return this._config;
    }
  },

  isEnabled: function() {
    console.log('this.config()', this.config());

    return (this.config() || {}).enable;
  },

  token: function() {
    var isTokenValid = 0;

    var token = this._token,
        paypalConfig = this._config;

    if (token) {
      isTokenValid = Math.ceil((new Date().getTime() - token.timestamp) / 1000);
    }
    if (isTokenValid === 0 || isTokenValid > token.expires_in && paypalConfig) {
      token = this._payaplToken();
      token.timestamp = new Date().getTime();
      token.expires_in -= 60; // minus 1 minute expires

      this._token = token;
    }

    return token;
  },

  _headers: function() {
    var token = this.token();
    return {
      'Authorization': 'Bearer ' + token.access_token,
      'Accept': 'application/json',
      'Content-Type': 'application/json'
    };
  },

  _payaplToken: function() {
    var paypalConfig = this._config;
    var auth = paypalConfig.clientId + ':' + paypalConfig.clientSecret;
      var token = EJSON.parse(Meteor.http.post(`${this._url}/v1/oauth2/token`, {
        headers: {
          'Accept': 'application/json',
          'Accept-Language': 'en_US'
        },
        auth: auth,
        params: {
          'grant_type': 'client_credentials'
        }
      }).content);

    return token;
  },

  paypalCreatePayment: function(payment) {
    var res = Meteor.http.post(`${this._url}/v1/payments/payment`, {
      headers: this._headers(),
      data: payment
    });
    return res;
  },

  paypalExecute: function(paymentId, payerId) {
    var url = `${this._url}/v1/payments/payment/${paymentId}/execute/`;
    var res = Meteor.http.post(url, {
      headers: this._headers(),
      data: {
        payer_id: payerId
      }
    });
    return res;
  },