1 files changed, 14 insertions, 0 deletions
diff --git a/netlib/http.py b/netlib/http.py
index 26438863..2c72621d 100644
--- a/netlib/http.py
+++ b/netlib/http.py
@@ -29,6 +29,20 @@ def _is_valid_host(host):
         return None
     return True
 
+def is_successful_upgrade(request, response):
+    """
+        determines if a client and server successfully agreed to an HTTP protocol upgrade
+
+        https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism
+    """
+    http_switching_protocols_code = 101
+    
+    if request and response:
+        responseUpgrade = request.headers.get("Upgrade")
+        requestUpgrade  = response.headers.get("Upgrade")
+        if response.code == http_switching_protocols_code and responseUpgrade == requestUpgrade:
+            return requestUpgrade[0] if len(requestUpgrade) > 0 else None
+    return None
 
 def parse_url(url):
     """