From 675b291d47f9eff3bc1aaa609b6849c42bb8d2f4 Mon Sep 17 00:00:00 2001
From: Sebastian Tabares Amaya <sytabaresa@gmail.com>
Date: Fri, 7 Jul 2017 09:12:11 -0500
Subject: [PATCH] MDL-59473 request: Fix Loop Redirection in Oauth2

---
 lib/oauthlib.php | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/oauthlib.php b/lib/oauthlib.php
index 8f3e7957959..f918112f118 100644
--- a/lib/oauthlib.php
+++ b/lib/oauthlib.php
@@ -557,6 +557,10 @@ abstract class oauth2_client extends curl {
 
         $r = json_decode($response);
 
+        if (is_null($r)) {
+            throw new moodle_exception("Could not decode JSON token response");
+        }
+
         if (!empty($r->error)) {
             throw new moodle_exception($r->error . ' ' . $r->error_description);
         }
@@ -610,6 +614,9 @@ abstract class oauth2_client extends curl {
             }
         }
 
+        // Force JSON format content in response.
+        $this->setHeader('Accept: application/json');
+
         $response = parent::request($murl->out(false), $options);
 
         $this->resetHeader();