wp_validate_auth_cookie

wp_validate_auth_cookie是一個WordPress函式，用來驗證一個認證cookie: 這個函式用來確定一個使用者是否登入到一個網站並有一個有效的認證cookie: 該函式將一個cookie作為其輸入，如果cookie是有效的，則返回使用者ID，如果不是，則返回false。

驗證認證 cookie。

檢查包括確保認證cookie被設定並拉入內容（如果沒有使用$cookie）。

確保cookie沒有過期。驗證cookie中的雜湊值是否符合要求，並對兩者進行比較。

function wp_validate_auth_cookie( $cookie = '', $scheme = '' ) {
		$cookie_elements = wp_parse_auth_cookie( $cookie, $scheme );
		if ( ! $cookie_elements ) {
			/**
			 * Fires if an authentication cookie is malformed.
			 *
			 * @since 2.7.0
			 *
			 * @param string $cookie Malformed auth cookie.
			 * @param string $scheme Authentication scheme. Values include 'auth', 'secure_auth',
			 *                       or 'logged_in'.
			 */
			do_action( 'auth_cookie_malformed', $cookie, $scheme );
			return false;
		}

		$scheme     = $cookie_elements['scheme'];
		$username   = $cookie_elements['username'];
		$hmac       = $cookie_elements['hmac'];
		$token      = $cookie_elements['token'];
		$expired    = $cookie_elements['expiration'];
		$expiration = $cookie_elements['expiration'];

		// Allow a grace period for POST and Ajax requests.
		if ( wp_doing_ajax() || 'POST' === $_SERVER['REQUEST_METHOD'] ) {
			$expired += HOUR_IN_SECONDS;
		}

		// Quick check to see if an honest cookie has expired.
		if ( $expired < time() ) {
			/**
			 * Fires once an authentication cookie has expired.
			 *
			 * @since 2.7.0
			 *
			 * @param string[] $cookie_elements {
			 *     Authentication cookie components. None of the components should be assumed
			 *     to be valid as they come directly from a client-provided cookie value.
			 *
			 *     @type string $username   User's username.
			 *     @type string $expiration The time the cookie expires as a UNIX timestamp.
			 *     @type string $token      User's session token used.
			 *     @type string $hmac       The security hash for the cookie.
			 *     @type string $scheme     The cookie scheme to use.
			 * }
			 */
			do_action( 'auth_cookie_expired', $cookie_elements );
			return false;
		}

		$user = get_user_by( 'login', $username );
		if ( ! $user ) {
			/**
			 * Fires if a bad username is entered in the user authentication process.
			 *
			 * @since 2.7.0
			 *
			 * @param string[] $cookie_elements {
			 *     Authentication cookie components. None of the components should be assumed
			 *     to be valid as they come directly from a client-provided cookie value.
			 *
			 *     @type string $username   User's username.
			 *     @type string $expiration The time the cookie expires as a UNIX timestamp.
			 *     @type string $token      User's session token used.
			 *     @type string $hmac       The security hash for the cookie.
			 *     @type string $scheme     The cookie scheme to use.
			 * }
			 */
			do_action( 'auth_cookie_bad_username', $cookie_elements );
			return false;
		}

		$pass_frag = substr( $user->user_pass, 8, 4 );

		$key = wp_hash( $username . '|' . $pass_frag . '|' . $expiration . '|' . $token, $scheme );

		// If ext/hash is not present, compat.php's hash_hmac() does not support sha256.
		$algo = function_exists( 'hash' ) ? 'sha256' : 'sha1';
		$hash = hash_hmac( $algo, $username . '|' . $expiration . '|' . $token, $key );

		if ( ! hash_equals( $hash, $hmac ) ) {
			/**
			 * Fires if a bad authentication cookie hash is encountered.
			 *
			 * @since 2.7.0
			 *
			 * @param string[] $cookie_elements {
			 *     Authentication cookie components. None of the components should be assumed
			 *     to be valid as they come directly from a client-provided cookie value.
			 *
			 *     @type string $username   User's username.
			 *     @type string $expiration The time the cookie expires as a UNIX timestamp.
			 *     @type string $token      User's session token used.
			 *     @type string $hmac       The security hash for the cookie.
			 *     @type string $scheme     The cookie scheme to use.
			 * }
			 */
			do_action( 'auth_cookie_bad_hash', $cookie_elements );
			return false;
		}

		$manager = WP_Session_Tokens::get_instance( $user->ID );
		if ( ! $manager->verify( $token ) ) {
			/**
			 * Fires if a bad session token is encountered.
			 *
			 * @since 4.0.0
			 *
			 * @param string[] $cookie_elements {
			 *     Authentication cookie components. None of the components should be assumed
			 *     to be valid as they come directly from a client-provided cookie value.
			 *
			 *     @type string $username   User's username.
			 *     @type string $expiration The time the cookie expires as a UNIX timestamp.
			 *     @type string $token      User's session token used.
			 *     @type string $hmac       The security hash for the cookie.
			 *     @type string $scheme     The cookie scheme to use.
			 * }
			 */
			do_action( 'auth_cookie_bad_session_token', $cookie_elements );
			return false;
		}

		// Ajax/POST grace period set above.
		if ( $expiration < time() ) {
			$GLOBALS['login_grace_period'] = 1;
		}

		/**
		 * Fires once an authentication cookie has been validated.
		 *
		 * @since 2.7.0
		 *
		 * @param string[] $cookie_elements {
		 *     Authentication cookie components.
		 *
		 *     @type string $username   User's username.
		 *     @type string $expiration The time the cookie expires as a UNIX timestamp.
		 *     @type string $token      User's session token used.
		 *     @type string $hmac       The security hash for the cookie.
		 *     @type string $scheme     The cookie scheme to use.
		 * }
		 * @param WP_User  $user            User object.
		 */
		do_action( 'auth_cookie_valid', $cookie_elements, $user );

		return $user->ID;
	}
endif;

if ( ! function_exists( 'wp_generate_auth_cookie' ) ) :
	/**
	 * Generates authentication cookie contents.
	 *
	 * @since 2.5.0
	 * @since 4.0.0 The `$token` parameter was added.
	 *
	 * @param int    $user_id    User ID.
	 * @param int    $expiration The time the cookie expires as a UNIX timestamp.
	 * @param string $scheme     Optional. The cookie scheme to use: 'auth', 'secure_auth', or 'logged_in'.
	 *                           Default 'auth'.
	 * @param string $token      User's session token to use for this cookie.
	 * @return string Authentication cookie contents. Empty string if user does not exist.
	 */