Salesforce Oauth redirect CORS issue node express app

Question

I've tried everything to get around the CORS error I am receiving. For oauth flow, to redirect your app to the Salesforce login screen (but this url auto redirects behind the scenes from salesforce to salesforce)

XMLHttpRequest cannot load salesforce url 2 Redirect from salesforce url 1 to salesforce oauth url 2 has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access.

I've installed CORS module and also tried this:

app.use('/public',function(req, res, next) {
res.setHeader("Access-Control-Allow-Origin", "*");
// Request headers you wish to allow
res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested- 
With, Content-Type, Accept");     
// Set to true if you need the website to include cookies in the  
requests sent   
res.setHeader('Access-Control-Allow-Credentials', true);
// Pass to next layer of middleware
next();
});

Can anyone actually get this working and help?

The error message indicates it’s a Salesforce URL which isn’t sending the Access-Control-Allow-Origin in its response. Enabling CORS in your own express app isn’t going to fix that. So you need to figure out if there are some Salesforce docs which explain the supported way for doing whatever it is you’re trying to do, or else set up a CORS proxy using the code from github.com/Rob--W/cors-anywhere or somewhere — sideshowbarker

Mukul Jain Mukul Jain · Accepted Answer · 2017-05-21T16:02:31

I just wrote a blog couple of days back: http://nodexperts.com/blog/salesforce-oauth-using-nodejs/

First of all, this will help you a lot in setting up OAuth2 and SalesForce in your Node-Express app.

Another thing is that you can go from your app -> SalesForce login app -> your_redirect_uri.

You will only get CORS error when you're doing this from server-to-server.

So, if you have an app which has some UI and some user interaction, then I would suggest you to redirect to SalesForce page from your client code.

Here's a snippet of how you can redirect to login page of Salesforce using express roure and jsforce npom package:

app.get('/oauth2/auth', function(req, res) {
  const oauth2 = new jsforce.OAuth2({
    clientId: process.env.CLIENT_ID,
    clientSecret: process.env.CLIENT_SECRET_ID,
    redirectUri: `${req.protocol}://${req.get('host')}/${process.env.REDIRECT_URI}`
  });
  res.redirect(oauth2.getAuthorizationUrl({}));
});

And this is how you can set your SalesForce conncted app, redirect url:

app.get('/redirect_uri', function(req,res) {
  const oauth2 = new jsforce.OAuth2({
    clientId: process.env.CLIENT_ID,
    clientSecret: process.env.CLIENT_SECRET_ID,
    redirectUri: `${req.protocol}://${req.get('host')}/${process.env.REDIRECT_URI}`
  });
  const conn = new jsforce.Connection({ oauth2 : oauth2 });

  conn.authorize(req.query.code, function(err, userInfo) {
    if (err) {
      return console.error(err);
    }
    console.log(conn.accessToken);
  });
});

Hope, everything is clear, let me know in case of any clarification.

Salesforce Oauth redirect CORS issue node express app

1 Answers