fix(runtime/http): Encode and decode headers as byte strings in the HTTP server (#11144)

cli/tests/unit/http_test.ts

@@ -543,3 +543,46 @@ unitTest(
     listener.close();
   },
 );
+
+unitTest({ perms: { net: true } }, async function httpRequestLatin1Headers() {
+  const promise = (async () => {
+    const listener = Deno.listen({ port: 4501 });
+    for await (const conn of listener) {
+      const httpConn = Deno.serveHttp(conn);
+      for await (const { request, respondWith } of httpConn) {
+        assertEquals(request.headers.get("X-Header-Test"), "á");
+        await respondWith(
+          new Response("", { headers: { "X-Header-Test": "Æ" } }),
+        );
+        httpConn.close();
+      }
+      break;
+    }
+  })();
+
+  const clientConn = await Deno.connect({ port: 4501 });
+  const requestText =
+    "GET / HTTP/1.1\r\nHost: 127.0.0.1:4501\r\nX-Header-Test: á\r\n\r\n";
+  const requestBytes = new Uint8Array(requestText.length);
+  for (let i = 0; i < requestText.length; i++) {
+    requestBytes[i] = requestText.charCodeAt(i);
+  }
+  let written = 0;
+  while (written < requestBytes.byteLength) {
+    written += await clientConn.write(requestBytes.slice(written));
+  }
+
+  let responseText = "";
+  const buf = new Uint8Array(1024);
+  let read;
+  while ((read = await clientConn.read(buf)) !== null) {
+    for (let i = 0; i < read; i++) {
+      responseText += String.fromCharCode(buf[i]);
+    }
+  }
+  clientConn.close();
+
+  assert(/\r\n[Xx]-[Hh]eader-[Tt]est: Æ\r\n/.test(responseText));
+
+  await promise;
+});

runtime/ops/http.rs

@@ -14,6 +14,7 @@ use deno_core::futures::StreamExt;
 use deno_core::op_async;
 use deno_core::op_sync;
 use deno_core::AsyncRefCell;
+use deno_core::ByteString;
 use deno_core::CancelHandle;
 use deno_core::CancelTryFuture;
 use deno_core::Extension;
@@ -140,9 +141,11 @@ struct NextRequestResponse(
   // response_sender_rid:
   ResourceId,
   // method:
+  // This is a String rather than a ByteString because reqwest will only return
+  // the method as a str which is guaranteed to be ASCII-only.
   String,
   // headers:
-  Vec<(String, String)>,
+  Vec<(ByteString, ByteString)>,
   // url:
   String,
 );
@@ -199,9 +202,10 @@ async fn op_http_request_next(
 
       let mut headers = Vec::with_capacity(req.headers().len());
       for (name, value) in req.headers().iter() {
-        let name = name.to_string();
-        let value = value.to_str().unwrap_or("").to_string();
-        headers.push((name, value));
+        let name: &[u8] = name.as_ref();
+        let value = value.as_bytes();
+        headers
+          .push((ByteString(name.to_owned()), ByteString(value.to_owned())));
       }
 
       let url = {
@@ -346,7 +350,7 @@ struct RespondArgs(
   // status:
   u16,
   // headers:
-  Vec<(String, String)>,
+  Vec<(ByteString, ByteString)>,
 );
 
 async fn op_http_response(
@@ -375,7 +379,7 @@ async fn op_http_response(
 
   builder.headers_mut().unwrap().reserve(headers.len());
   for (key, value) in &headers {
-    builder = builder.header(key, value);
+    builder = builder.header(key.as_ref(), value.as_ref());
   }
 
   let res;