Add sni_hostname extension

Author: karpetrosyan

httpcore/_async/connection.py

@@ -91,6 +91,7 @@ async def handle_async_request(self, request: Request) -> Response:
 
     async def _connect(self, request: Request) -> AsyncNetworkStream:
         timeouts = request.extensions.get("timeout", {})
+        sni_hostname = request.extensions.get("sni_hostname", None)
         timeout = timeouts.get("connect", None)
 
         retries_left = self._retries
@@ -143,7 +144,7 @@ async def _connect(self, request: Request) -> AsyncNetworkStream:
 
             kwargs = {
                 "ssl_context": ssl_context,
-                "server_hostname": self._origin.host.decode("ascii"),
+                "server_hostname": sni_hostname or self._origin.host.decode("ascii"),
                 "timeout": timeout,
             }
             async with Trace("connection.start_tls", request, kwargs) as trace:

httpcore/_sync/connection.py

@@ -91,6 +91,7 @@ def handle_request(self, request: Request) -> Response:
 
     def _connect(self, request: Request) -> NetworkStream:
         timeouts = request.extensions.get("timeout", {})
+        sni_hostname = request.extensions.get("sni_hostname", None)
         timeout = timeouts.get("connect", None)
 
         retries_left = self._retries
@@ -143,7 +144,7 @@ def _connect(self, request: Request) -> NetworkStream:
 
             kwargs = {
                 "ssl_context": ssl_context,
-                "server_hostname": self._origin.host.decode("ascii"),
+                "server_hostname": sni_hostname or self._origin.host.decode("ascii"),
                 "timeout": timeout,
             }
             with Trace("connection.start_tls", request, kwargs) as trace: