Started to implement server

vendor/deno.land/std@0.191.0/io/limited_reader.ts

@@ -0,0 +1,31 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// This module is browser compatible.
+
+/**
+ * A `LimitedReader` reads from `reader` but limits the amount of data returned to just `limit` bytes.
+ * Each call to `read` updates `limit` to reflect the new amount remaining.
+ * `read` returns `null` when `limit` <= `0` or
+ * when the underlying `reader` returns `null`.
+ */
+import type { Reader } from "../types.d.ts";
+
+export class LimitedReader implements Reader {
+  constructor(public reader: Reader, public limit: number) {}
+
+  async read(p: Uint8Array): Promise<number | null> {
+    if (this.limit <= 0) {
+      return null;
+    }
+
+    if (p.length > this.limit) {
+      p = p.subarray(0, this.limit);
+    }
+    const n = await this.reader.read(p);
+    if (n == null) {
+      return null;
+    }
+
+    this.limit -= n;
+    return n;
+  }
+}