Handle comma-separated values in x-forwarded-port header

Author: lucadelauw

azure/functions/_http_wsgi.py

@@ -113,7 +113,9 @@ def to_environ(self, errors_buffer: StringIO) -> Dict[str, Any]:
     def _get_port(self, parsed_url, lowercased_headers: Dict[str, str]) -> int:
         port: int = 80
         if lowercased_headers.get('x-forwarded-port'):
-            return int(lowercased_headers['x-forwarded-port'])
+            # Handle comma-separated port values (e.g., "443,8080,433")
+            forwarded_port = lowercased_headers['x-forwarded-port'].split(',')[0].strip()
+            return int(forwarded_port)
         elif getattr(parsed_url, 'port', None):
             return int(parsed_url.port)
         elif parsed_url.scheme == 'https':

tests/test_http_wsgi.py

@@ -100,6 +100,24 @@ def test_request_protocol_by_header(self):
         self.assertEqual(environ['SERVER_PORT'], str(8081))
         self.assertEqual(environ['wsgi.url_scheme'], 'https')
 
+    def test_request_protocol_by_header_with_multiple_ports(self):
+        func_request = self._generate_func_request(headers={
+            "x-forwarded-port": "443,8080,433"
+        })
+        error_buffer = StringIO()
+        environ = WsgiRequest(func_request).to_environ(error_buffer)
+        self.assertEqual(environ['SERVER_PORT'], str(443))
+        self.assertEqual(environ['wsgi.url_scheme'], 'https')
+
+    def test_request_protocol_by_header_with_spaces(self):
+        func_request = self._generate_func_request(headers={
+            "x-forwarded-port": " 8443 , 8080 "
+        })
+        error_buffer = StringIO()
+        environ = WsgiRequest(func_request).to_environ(error_buffer)
+        self.assertEqual(environ['SERVER_PORT'], str(8443))
+        self.assertEqual(environ['wsgi.url_scheme'], 'https')
+
     def test_request_protocol_by_scheme(self):
         func_request = self._generate_func_request(url="http://a.b.com")
         error_buffer = StringIO()