fast path for string responses

js/bootstrap/index.js

@@ -5,6 +5,8 @@
   delete self._startResponse;
   const writeResponse = self._writeResponse;
   delete self._writeResponse;
+  const stringResponse = self._stringResponse;
+  delete self._stringResponse;
   const setTimeout = self._setTimeout;
   delete self._setTimeout;
   const setInterval = self._setInterval;
@@ -263,11 +265,7 @@
       response = await fn(request, generateContextObject(url));
       switch (typeof response) {
         case 'string': {
-          const headers = new Headers({
-            'Content-Type': 'text/plain'
-          });
-
-          response = new Response(response, { headers });
+          // handle it in native code
           break;
         }
         case 'object': {
@@ -304,7 +302,9 @@
       response = new Response('', { status: 500 });
     }
 
-    if (response.body) {
+    if (typeof response === 'string') {
+      stringResponse(response, reqId);
+    } else if (response.body) {
       startResponse(response, reqId);
       let stream =
         response.body instanceof TransformStream

osgood-v8/src/wrapper/local.rs

@@ -128,6 +128,7 @@ persistent!(
 persistent!(V8::Module, persistent_from_module, persistent_to_module);
 persistent!(V8::Message, persistent_from_message, persistent_to_message);
 each_valuable_type!(V8::Object);
+each_valuable_type!(V8::Map);
 each_valuable_type!(V8::Array);
 each_valuable_type!(V8::String);
 each_valuable_type!(V8::Primitive);

src/worker.rs

@@ -222,6 +222,7 @@ fn make_globals(mut context: Local<Context>, route: &str) {
     global.set("_route", route);
     global.set_extern_method(context, "_startResponse", inbound::start_response);
     global.set_extern_method(context, "_writeResponse", inbound::write_response);
+    global.set_extern_method(context, "_stringResponse", inbound::string_response);
     global.set_extern_method(context, "_setFetchHandler", fetch::set_fetch_handler);
     global.set_extern_method(context, "_setTimerHandler", timers::set_timer_handler);
     global.set_extern_method(

src/worker/inbound.rs

@@ -1,4 +1,5 @@
 use super::*;
+use hyper::header::HeaderValue;
 
 enum ResponseHolder {
     Resp(body::Sender),
@@ -97,6 +98,14 @@ pub fn call_inbound_req_body_handler(mut context: Local<V8::Context>, args: Vec<
         .call(context, &null, args);
 }
 
+#[v8_fn]
+pub fn string_response(args: FunctionCallbackInfo) {
+    let req_id = args.get(1).unwrap().to_number().value() as i32;
+    let mut response = Response::new(args.get(0).unwrap().as_rust_string().into());
+    (*response.headers_mut()).insert("Content-Type", HeaderValue::from_str("text/plain").unwrap());
+    send_response!(&req_id, Ok(response));
+}
+
 #[v8_fn]
 pub fn start_response(args: FunctionCallbackInfo) {
     let context = get_context();