Hi Everyone,

I am new to Salesforce coding and learning to integrate with Salesforce. I am facing issue as mentioned below.

Scenario - I am integrating two Salesforce instance using APEX Callout and REST API. In the source SFDC instance I have created a trigger on the Account Object that calls a class with @future annotation. This class sends out a HTTP Request to the other SFDC instance using Web Server Authentication Flow.

Issue Description - Per the defined steps in 'Getting Started with the Force.com REST API' guide, I create a Connected App record in the Destination SFDC instance. But when the APEX code is requesting the Salesforce Authorization Endpoint with the relevant parameters (response_type, client_id, redirect_uri), I am not able to retrieve the Authorization Code (Code) that comes along with the Callback URL.
Though, I am successfully redirected to the callback URL (appended with the code) when I am using a browser. See below the request and the redirected response I get when I do it in a browser - 
HTTP Request:
https://login.salesforce.com/services/oauth2/authorize?response_type=code&client_id=[client_id taken from the Connected App record]&redirect_uri=https://localhost:8443/RestTest/oauth/_callback&immediate=true
HTTP Response:
http://localhost:8443/RestTest/oauth/_callback?code=[aPrxg.........]%3D%3D

Problem Statements - 
1. On the first place, is it possible to programmatically extract the code from the HTTP response?

2. If the answer to the above question is 'Yes', then please suggest, how? What are the relevant methods to extract this information.

Thanks
Anupam