From dbd2a84d0a49336b1c249aff4916b5a0614ba224 Mon Sep 17 00:00:00 2001
From: Marcos <merick16@gmail.com>
Date: Wed, 7 Jul 2021 15:01:46 -0500
Subject: [PATCH] Update __init__.py

Support for Sha 256 Signature Method
---
 oauth2/__init__.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/oauth2/__init__.py b/oauth2/__init__.py
index 38bf520b..b0924261 100644
--- a/oauth2/__init__.py
+++ b/oauth2/__init__.py
@@ -24,6 +24,7 @@
 
 import base64
 from hashlib import sha1
+from hashlib import sha256
 import time
 import random
 import hmac
@@ -848,7 +849,36 @@ def sign(self, request, consumer, token):
         # Calculate the digest base 64.
         return binascii.b2a_base64(hashed.digest())[:-1]
 
+    
+class SignatureMethod_HMAC_SHA256(SignatureMethod):
+    name = 'HMAC-SHA256'
 
+    def signing_base(self, request, consumer, token):
+        if (not hasattr(request, 'normalized_url') or request.normalized_url is None):
+            raise ValueError("Base URL for request is not set.")
+
+        sig = (
+            escape(request.method),
+            escape(request.normalized_url),
+            escape(request.get_normalized_parameters()),
+        )
+
+        key = '%s&' % escape(consumer.secret)
+        if token:
+            key += escape(token.secret)
+        raw = '&'.join(sig)
+        return key.encode('ascii'), raw.encode('ascii')
+
+    def sign(self, request, consumer, token):
+        """Builds the base signature string."""
+        key, raw = self.signing_base(request, consumer, token)
+
+        hashed = hmac.new(key, raw, sha256)
+
+        # Calculate the digest base 64.
+        return binascii.b2a_base64(hashed.digest())[:-1]
+
+    
 class SignatureMethod_PLAINTEXT(SignatureMethod):
 
     name = 'PLAINTEXT'