Started to implement server

vendor/deno.land/std@0.178.0/encoding/base64url.ts

@@ -0,0 +1,70 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+/**
+ * {@linkcode encode} and {@linkcode decode} for
+ * [base64 URL safe](https://en.wikipedia.org/wiki/Base64#URL_applications) encoding.
+ *
+ * This module is browser compatible.
+ *
+ * @example
+ * ```ts
+ * import {
+ *   decode,
+ *   encode,
+ * } from "https://deno.land/std@$STD_VERSION/encoding/base64url.ts";
+ *
+ * const binary = new TextEncoder().encode("foobar");
+ * const encoded = encode(binary);
+ * console.log(encoded);
+ * // => "Zm9vYmFy"
+ *
+ * console.log(decode(encoded));
+ * // => Uint8Array(6) [ 102, 111, 111, 98, 97, 114 ]
+ * ```
+ *
+ * @module
+ */
+
+import * as base64 from "./base64.ts";
+
+/*
+ * Some variants allow or require omitting the padding '=' signs:
+ * https://en.wikipedia.org/wiki/Base64#The_URL_applications
+ * @param base64url
+ */
+function addPaddingToBase64url(base64url: string): string {
+  if (base64url.length % 4 === 2) return base64url + "==";
+  if (base64url.length % 4 === 3) return base64url + "=";
+  if (base64url.length % 4 === 1) {
+    throw new TypeError("Illegal base64url string!");
+  }
+  return base64url;
+}
+
+function convertBase64urlToBase64(b64url: string): string {
+  if (!/^[-_A-Z0-9]*?={0,2}$/i.test(b64url)) {
+    // Contains characters not part of base64url spec.
+    throw new TypeError("Failed to decode base64url: invalid character");
+  }
+  return addPaddingToBase64url(b64url).replace(/\-/g, "+").replace(/_/g, "/");
+}
+
+function convertBase64ToBase64url(b64: string): string {
+  return b64.replace(/=/g, "").replace(/\+/g, "-").replace(/\//g, "_");
+}
+
+/**
+ * Encodes a given ArrayBuffer or string into a base64url representation
+ * @param data
+ */
+export function encode(data: ArrayBuffer | string): string {
+  return convertBase64ToBase64url(base64.encode(data));
+}
+
+/**
+ * Converts given base64url encoded data back to original
+ * @param b64url
+ */
+export function decode(b64url: string): Uint8Array {
+  return base64.decode(convertBase64urlToBase64(b64url));
+}