A proxy server to access Salesforce API from JSforce JavaScript apps served outside of Salesforce.

As the same origin policy restricts communication to the Salesforce API from outer domain, you should serve cross-domain proxy server when you build a app using JSforce outside of Salesforce.

As Salesforce REST API supports CORS (Cross-Origin Resource Sharing) access, this proxy is not always required when you are using only REST API and you can change security setting in your connecting organization. This proxy is still useful because you can access not only REST APIs but also SOAP-based APIs from outer domain.

Start proxy server in your server environment which can run Node.js app (Heroku is the one you might choose).

Install required packages :

$ npm install

Run proxy server :

$ npm start

When you use JSforce in your JavaScript app, set proxyUrl when creating Connection instance.

var conn = jsforce.Connection({
  accessToken: '<access_token>',
  instanceUrl: '<instance_url>',
  proxyUrl: 'https://your-ajax-proxy-service.herokuapp.com/proxy/'
});

conn.query('SELECT Id, Name FROM Account', function(err, res) {
  // ...
});

Ajax proxy is not only provided in standalone server but also works as connect middleware. You can include the proxy functionality in your express.js app.

First install jsforce-ajax-proxy in your app project:

$ npm install jsforce-ajax-proxy --save

Then include the middleware under certain path:

var express = require('express');
var jsforceAjaxProxy = require('jsforce-ajax-proxy');
var app = express();

app.all('/proxy/?*', jsforceAjaxProxy());

If you want to accept http request from other origin, set enableCORS option to true.

app.all('/proxy/?*', jsforceAjaxProxy({ enableCORS: true });

You don't have to use this app when you are building a JSforce app in Visualforce, because it works in the same domain as Salesforce API.