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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.import { decodeHex, encodeHex } from "../encoding/hex.ts";
const encoder = new TextEncoder();
function splitByLast(value: string, separator: string): [string, string] {  const index = value.lastIndexOf(separator);  return index === -1    ? [value, ""]    : [value.slice(0, index), value.slice(index + 1)];}
/** * Returns a promise with the signed cookie value from the given cryptographic * key. * * @example * ```ts * import { signCookie } from "https://deno.land/std@$STD_VERSION/http/unstable_signed_cookie.ts"; * import { setCookie } from "https://deno.land/std@$STD_VERSION/http/cookie.ts"; * * const key = await crypto.subtle.generateKey( *   { name: "HMAC", hash: "SHA-256" }, *   true, *   ["sign", "verify"], * ); * const value = await signCookie("my-cookie-value", key); * * const headers = new Headers(); * setCookie(headers, { *   name: "my-cookie-name", *   value, * }); * * const cookieHeader = headers.get("set-cookie"); * ``` */export async function signCookie(  value: string,  key: CryptoKey,): Promise<string> {  const data = encoder.encode(value);  const signature = await crypto.subtle.sign("HMAC", key, data);  const signatureHex = encodeHex(signature);  return `${value}.${signatureHex}`;}
/** * Returns a promise of a boolean indicating whether the signed cookie is valid. * * @example * ```ts * import { verifyCookie } from "https://deno.land/std@$STD_VERSION/http/unstable_signed_cookie.ts"; * import { getCookies } from "https://deno.land/std@$STD_VERSION/http/cookie.ts"; * * const key = await crypto.subtle.generateKey( *   { name: "HMAC", hash: "SHA-256" }, *   true, *   ["sign", "verify"], * ); * * const headers = new Headers({ *   Cookie: "location=tokyo.37f7481039762eef5cd46669f93c0a3214dfecba7d0cdc0b0dc40036063fb22e", * }); * const signedCookie = getCookies(headers)["location"]; * if (signedCookie === undefined) throw new Error("Cookie not found"); * await verifyCookie(signedCookie, key); * ``` */export async function verifyCookie(  signedCookie: string,  key: CryptoKey,): Promise<boolean> {  const [value, signatureHex] = splitByLast(signedCookie, ".");  if (!value || !signatureHex) return false;
  const data = encoder.encode(value);  const signature = decodeHex(signatureHex);
  return await crypto.subtle.verify("HMAC", key, signature, data);}
/** * Parses a signed cookie to get its value. * * Important: always verify the cookie using {@linkcode verifyCookie} first. * * @example * ```ts * import { verifyCookie, parseSignedCookie } from "https://deno.land/std@$STD_VERSION/http/unstable_signed_cookie.ts"; * import { getCookies } from "https://deno.land/std@$STD_VERSION/http/cookie.ts"; * * const key = await crypto.subtle.generateKey( *   { name: "HMAC", hash: "SHA-256" }, *   true, *   ["sign", "verify"], * ); * * const headers = new Headers({ *   Cookie: "location=tokyo.37f7481039762eef5cd46669f93c0a3214dfecba7d0cdc0b0dc40036063fb22e", * }); * const signedCookie = getCookies(headers)["location"]; * if (signedCookie === undefined) throw new Error("Cookie not found"); * await verifyCookie(signedCookie, key); * const cookie = parseSignedCookie(signedCookie); * ``` */export function parseSignedCookie(signedCookie: string): string {  return splitByLast(signedCookie, ".")[0];}