2 files changed, 58 insertions, 0 deletions
diff --git a/cli/dts/lib.deno.unstable.d.ts b/cli/dts/lib.deno.unstable.d.ts
index 9ab9b5761..a61d672f7 100644
--- a/cli/dts/lib.deno.unstable.d.ts
+++ b/cli/dts/lib.deno.unstable.d.ts
@@ -1333,6 +1333,20 @@ declare namespace Deno {
    * Make the timer of the given id not blocking the event loop from finishing
    */
   export function unrefTimer(id: number): void;
+
+  /** **UNSTABLE**: new API, yet to be vetter.
+   *
+   * Allows to "hijack" a connection that the request is associated with.
+   * Can be used to implement protocols that build on top of HTTP (eg.
+   * WebSockets).
+   *
+   * The returned promise returns underlying connection and first packet
+   * received. The promise shouldn't be awaited before responding to the
+   * `request`, otherwise event loop might deadlock.
+   */
+  export function upgradeHttp(
+    request: Request,
+  ): Promise<[Deno.Conn, Uint8Array]>;
 }
 
 declare function fetch(
diff --git a/cli/tests/unit/http_test.ts b/cli/tests/unit/http_test.ts
index 65ee55577..fd8d49947 100644
--- a/cli/tests/unit/http_test.ts
+++ b/cli/tests/unit/http_test.ts
@@ -5,6 +5,7 @@ import {
   BufWriter,
 } from "../../../test_util/std/io/buffer.ts";
 import { TextProtoReader } from "../../../test_util/std/textproto/mod.ts";
+import { serve } from "../../../test_util/std/http/server.ts";
 import {
   assert,
   assertEquals,
@@ -1738,6 +1739,49 @@ Deno.test({
   },
 });
 
+Deno.test("upgradeHttp", async () => {
+  async function client() {
+    const tcpConn = await Deno.connect({ port: 4501 });
+    await tcpConn.write(
+      new TextEncoder().encode(
+        "CONNECT server.example.com:80 HTTP/1.1\r\n\r\nbla bla bla\nbla bla\nbla\n",
+      ),
+    );
+    setTimeout(async () => {
+      await tcpConn.write(
+        new TextEncoder().encode(
+          "bla bla bla\nbla bla\nbla\n",
+        ),
+      );
+      tcpConn.close();
+    }, 500);
+  }
+
+  const abortController = new AbortController();
+  const signal = abortController.signal;
+
+  const server = serve((req) => {
+    const p = Deno.upgradeHttp(req);
+
+    (async () => {
+      const [conn, firstPacket] = await p;
+      const buf = new Uint8Array(1024);
+      const firstPacketText = new TextDecoder().decode(firstPacket);
+      assertEquals(firstPacketText, "bla bla bla\nbla bla\nbla\n");
+      const n = await conn.read(buf);
+      assert(n != null);
+      const secondPacketText = new TextDecoder().decode(buf.slice(0, n));
+      assertEquals(secondPacketText, "bla bla bla\nbla bla\nbla\n");
+      abortController.abort();
+      conn.close();
+    })();
+
+    return new Response(null, { status: 101 });
+  }, { port: 4501, signal });
+
+  await Promise.all([server, client()]);
+});
+
 function chunkedBodyReader(h: Headers, r: BufReader): Deno.Reader {
   // Based on https://tools.ietf.org/html/rfc2616#section-19.4.6
   const tp = new TextProtoReader(r);