Add Chunked Encoding to minimize memory usage for

large dynamic html pages.

adafruit_httpserver/response.py

@@ -69,6 +69,7 @@ def _construct_response_bytes(  # pylint: disable=too-many-arguments
         cache: int = 0,
         headers: Dict[str, str] = None,
         body: str = "",
+        chunked: bool = False,
     ) -> bytes:
         """Constructs the response bytes from the given parameters."""
 
@@ -77,7 +78,10 @@ def _construct_response_bytes(  # pylint: disable=too-many-arguments
         headers = headers or {}
 
         headers.setdefault("Content-Type", content_type)
-        headers.setdefault("Content-Length", content_length or len(body))
+        if chunked:
+            headers.setdefault("Transfer-Encoding", "chunked")
+        else:
+            headers.setdefault("Content-Length", content_length or len(body))
         headers.setdefault("Connection", "close")
 
         response += f"Cache-Control: max-age={cache}\r\n"
@@ -120,6 +124,33 @@ def send(self, conn: Union["SocketPool.Socket", "socket.socket"]) -> None:
                 body=self.body,
             )
 
+    def send_chunk_headers(
+        self, conn: Union["SocketPool.Socket", "socket.socket"]
+    ) -> None:
+        """Send Headers for a chunked response over the given socket."""
+        self._send_bytes(
+            conn,
+            self._construct_response_bytes(
+                status=self.status,
+                content_type=self.content_type,
+                chunked=True,
+                cache=self.cache,
+                body="",
+            ),
+        )
+
+    def send_body_chunk(
+        self, conn: Union["SocketPool.Socket", "socket.socket"], chunk: str
+    ) -> None:
+        """Send chunk of data to the given socket.  Send an empty("") chunk to finish the session.
+
+        :param Union["SocketPool.Socket", "socket.socket"] conn: Current connection.
+        :param str chunk: String data to be sent.
+        """
+        size = "%X\r\n".encode() % len(chunk)
+        self._send_bytes(conn, size)
+        self._send_bytes(conn, chunk.encode() + b"\r\n")
+
     def _send_response(  # pylint: disable=too-many-arguments
         self,
         conn: Union["SocketPool.Socket", "socket.socket"],

adafruit_httpserver/server.py

@@ -53,6 +53,17 @@ def route_func(request):
                 print("Received a request of length", len(raw_text), "bytes")
                 return HTTPResponse(body="hello world")
 
+
+            @server.route(path, method)
+            def route_func(request, conn):
+                raw_text = request.raw_request.decode("utf8")
+                print("Received a request of length", len(raw_text), "bytes")
+                res = HTTPResponse(content_type="text/html")
+                res.send_chunk_headers(conn)
+                res.send_body_chunk(conn, "Some content")
+                res.send_body_chunk(conn, "Some more content")
+                res.send_body_chunk(conn, "")  # Send empty packet to finish chunked stream
+                return None  # Return None, so server knows that nothing else needs to be sent.
         """
 
         def route_decorator(func: Callable) -> Callable:
@@ -162,7 +173,13 @@ def poll(self):
 
                 # If a handler for route exists and is callable, call it.
                 if handler is not None and callable(handler):
-                    response = handler(request)
+                    # Need to pass connection for chunked encoding to work.
+                    try:
+                        response = handler(request, conn)
+                    except TypeError:
+                        response = handler(request)
+                    if response is None:
+                        return
 
                 # If no handler exists and request method is GET, try to serve a file.
                 elif request.method == HTTPMethod.GET: