Salesforce OAuth with REST API using Javascript

Question

I have an app in my salesforce developer account that I want to allow my users to access from a remote app that I am building. I see that I must use OAuth2.0 to first authorize my users before they are allowed to access the salesforce data. At the moment I am trying to use the username-password OAuth flow described on salesforce.

Step 1) I request access token using username and password via the below code snippet

var password = 'userPassword' + 'securityToken'
$.ajax({
    type: 'GET',
    url: 'https://login.salesforce.com/services/oauth2/token',
    contentType: 'application/json',
    dataType: 'json',
    beforeSend: function(xhr) {
        xhr.setRequestHeader('grant_type','password'),
        xhr.setRequestHeader('client_id',  '<client_id_here>'),
        xhr.setRequestHeader('client_secret', '<client_secret_here'),
        xhr.setRequestHeader('username', '[email protected]'),
        xhr.setRequestHeader('password', "password")
    },
    success: function(response) {
        console.log('Successfully retrieved ' + response);
        //Other logic here
    },
    error: function(response) {
        console.log('Failed ' + response.status + ' ' + response.statusText);
        //Other logic here
    }
});

My request, however, is failing with the following message:

1) OPTIONS https://login.salesforce.com/services/oauth2/token 400 (Bad Request) 

2) XMLHttpRequest cannot load https://login.salesforce.com/services/oauth2/token. No 
  'Access- Control-Allow-Origin' header is present on the requested resource. 
   Origin   http://localhost is therefore not allowed access. 

I have seen some sources (here here here) mention that CORS is not supported in salesforce, and that another solution should be used. Some solutions I have seen are Salesforce APEX code, AJAX toolkit, or ForceTK.

In summary, I am looking to see if (1) there is a simple mistake that I am making with my above request to get the OAuth access_token (2) or if I need to do something different to get the access (3) is there a better way to login users and access their salesforce data from my connected app?

All and any help is appreciated!

Macruran

Your approach to implement OAuth2.0 entirely in the front end will always face the CORS problem. – Fitted

The error is indeed because CORS is not supported. So, you are right, you need to handle it differently. You need server-side code to handle this. – Nicaragua

Is there a best approach to handling OAuth for salesforce server-side? Salesforce APEX code or AJAX toolkit? I tried using [salesforce.stackexchange.com/questions/17382/… example) and get a "Refused to set unsafe header "User-Agent" message. – Macruran

Is the AJAX Toolkit available to external apps or only to VisualForce pages? – Ynez

Answer 1

You will need to handle the OAUTH part on your own server. This isn't just due to lack of CORS, there is also no way to securely OAUTH purely on the client-side. The server could really be anything but here is an example server written in Java using Play Framework which has a JavaScript / AngularJS client as well: http://typesafe.com/activator/template/reactive-salesforce-rest-javascript-seed

Ginnie

Answer 2

You can not make this request from JavaScript. You'll need to make a server side request. There are many implementations of this flow in PHP, C#, Java, etc.

Fujimoto

Is this going to be the case for all requests that I make from Salesforce because they don't allow CORS? Or will I be able to access their RESTful API from Javascript after I get through the OAuth process using a server-side request? – Macruran

Once you get through the OAuth process and have an active access token, you should be able to make an API Request from the client. See this page for more info: developer.salesforce.com/page/… – Fujimoto

Answer 3

I'm posting my ajax code here that has worked for me and this CORS error in console doesn't matter. If you see in network you will get the access token. see the ajax code below.

function gettoken()
{
    var param = {
      grant_type: "password",
      client_id : "id here",
      client_secret : "seceret here ",
      username:"username",
      password:"password with full key provided by sf"};
$.ajax({
    url: 'https://test.salesforce.com/services/oauth2/token',
    type: 'POST',
    data: param,
    dataType: "json",
    contentType: "application/x-www-form-urlencoded",
    success: function (data) {
        alert(data);
    }

});
}

I hope this will work for you perfectly.

Ariminum

Of course the response contains the token. But no JS will be allowed to access and use this token. So yeah.... your Answer is right but does not solve the issue itself... – Natant

Answer 4

I think you need to add the origin URL/IP in CORS setting as well in salesforce if you are making a request from Javascript app so it can get access to salesforce data.

Bergman

This is rather a comment than an answer. – Tartuffery