WordPress/wp-includes/session.php

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<?php
/**
* Abstract class for managing user session tokens.
*
* @since 4.0.0
*/
abstract class WP_Session_Tokens {
/**
* User ID.
*
* @since 4.0.0
*
* @var int User ID.
*/
protected $user_id;
/**
* Protected constructor.
*
* @param int $user_id User whose session to manage.
*/
protected function __construct( $user_id ) {
$this->user_id = $user_id;
}
/**
* Get a session token manager instance for a user.
*
* This method contains a filter that allows a plugin to swap out
* the session manager for a subclass of WP_Session_Tokens.
*
* @since 4.0.0
*
* @param int $user_id User whose session to manage.
*/
final public static function get_instance( $user_id ) {
/**
* Filter the session token manager used.
*
* @since 4.0.0
*
* @param string $session Name of class to use as the manager.
* Default 'WP_User_Meta_Session_Tokens'.
*/
$manager = apply_filters( 'session_token_manager', 'WP_User_Meta_Session_Tokens' );
return new $manager( $user_id );
}
/**
* Hashes a token for storage.
*
* @since 4.0.0
*
* @param string $token Token to hash.
* @return string A hash of the token (a verifier).
*/
final private function hash_token( $token ) {
return hash( 'sha256', $token );
}
/**
* Validate a user's session token as authentic.
*
* Checks that the given token is present and hasn't expired.
*
* @since 4.0.0
*
* @param string $token Token to verify.
* @return bool Whether the token is valid for the user.
*/
final public function verify_token( $token ) {
$verifier = $this->hash_token( $token );
return (bool) $this->get_session( $verifier );
}
/**
* Generate a cookie session identification token.
*
* A session identification token is a long, random string. It is used to
* link a cookie to an expiration time and to ensure that cookies become
* invalidated upon logout. This function generates a token and stores it
* with the associated expiration time.
*
* @since 4.0.0
*
* @param int $expiration Session expiration timestamp.
* @return string Session identification token.
*/
final public function create_token( $expiration ) {
/**
* Filter the information attached to the newly created session.
*
* Could be used in the future to attach information such as
* IP address or user agent to a session.
*
* @since 4.0.0
*
* @param array $session Array of extra data.
* @param int $user_id User ID.
*/
$session = apply_filters( 'attach_session_information', array(), $this->user_id );
$session['expiration'] = $expiration;
$token = wp_generate_password( 43, false, false );
$this->update_token( $token, $session );
return $token;
}
/**
* Updates a session based on its token.
*
* @since 4.0.0
*
* @param string $token Token to update.
* @param array $session Session information.
*/
final public function update_token( $token, $session ) {
$verifier = $this->hash_token( $token );
$this->update_session( $verifier, $session );
}
/**
* Destroy a session token.
*
* @since 4.0.0
*
* @param string $token Token to destroy.
*/
final public function destroy_token( $token ) {
$verifier = $this->hash_token( $token );
$this->update_session( $verifier, null );
}
/**
* Destroy all session tokens for this user,
* except a single token, presumably the one in use.
*
* @since 4.0.0
*
* @param string $token_to_keep Token to keep.
*/
final public function destroy_other_tokens( $token_to_keep ) {
$verifier = $this->hash_token( $token_to_keep );
$session = $this->get_session( $verifier );
if ( $session ) {
$this->destroy_other_sessions( $verifier );
} else {
$this->destroy_all_tokens();
}
}
/**
* Determine whether a session token is still valid,
* based on expiration.
*
* @since 4.0.0
*
* @param array $session Session to check.
* @return bool Whether session is valid.
*/
final protected function is_still_valid( $session ) {
return $session['expiration'] >= time();
}
/**
* Destroy all tokens for a user.
*
* @since 4.0.0
*/
final public function destroy_all_tokens() {
$this->destroy_all_sessions();
}
/**
* Destroy all tokens for all users.
*
* @since 4.0.0
*/
final public static function destroy_all_tokens_for_all_users() {
$manager = apply_filters( 'session_token_manager', 'WP_User_Meta_Session_Tokens' );
call_user_func( array( $manager, 'drop_sessions' ) );
}
/**
* Retrieve all sessions of a user.
*
* @since 4.0.0
*
* @return array Sessions of a user.
*/
final public function get_all_sessions() {
return array_values( $this->get_sessions() );
}
/**
* This method should retrieve all sessions of a user, keyed by verifier.
*
* @since 4.0.0
*
* @return array Sessions of a user, keyed by verifier.
*/
abstract protected function get_sessions();
/**
* This method should look up a session by its verifier (token hash).
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to retrieve.
* @return array|null The session, or null if it does not exist.
*/
abstract protected function get_session( $verifier );
/**
* This method should update a session by its verifier.
*
* Omitting the second argument should destroy the session.
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to update.
*/
abstract protected function update_session( $verifier, $session = null );
/**
* This method should destroy all session tokens for this user,
* except a single session passed.
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to keep.
*/
abstract protected function destroy_other_sessions( $verifier );
/**
* This method should destroy all sessions for a user.
*
* @since 4.0.0
*/
abstract protected function destroy_all_sessions();
/**
* This static method should destroy all session tokens for all users.
*
* @since 4.0.0
*/
abstract public static function drop_sessions();
}
/**
* Meta-based user sessions token manager.
*
* @since 4.0.0
*/
class WP_User_Meta_Session_Tokens extends WP_Session_Tokens {
/**
* Get all sessions of a user.
*
* @since 4.0.0
*
* @return array Sessions of a user.
*/
protected function get_sessions() {
$sessions = get_user_meta( $this->user_id, 'session_tokens', true );
if ( ! is_array( $sessions ) ) {
return array();
}
$sessions = array_map( array( $this, 'prepare_session' ), $sessions );
return array_filter( $sessions, array( $this, 'is_still_valid' ) );
}
/**
* Converts an expiration to an array of session information.
*
* @param mixed $session Session or expiration.
* @return array Session.
*/
protected function prepare_session( $session ) {
if ( is_int( $session ) ) {
return array( 'expiration' => $session );
}
return $session;
}
/**
* Retrieve a session by its verifier (token hash).
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to retrieve.
* @return array|null The session, or null if it does not exist
*/
protected function get_session( $verifier ) {
$sessions = $this->get_sessions();
if ( isset( $sessions[ $verifier ] ) ) {
return $sessions[ $verifier ];
}
return null;
}
/**
* Update a session by its verifier.
*
* Omitting the second argument destroys the session.
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to update.
*/
protected function update_session( $verifier, $session = null ) {
$sessions = $this->get_sessions();
if ( $session ) {
$sessions[ $verifier ] = $session;
} else {
unset( $sessions[ $verifier ] );
}
$this->update_sessions( $sessions );
}
/**
* Update a user's sessions in the usermeta table.
*
* @since 4.0.0
*
* @param array $sessions
*/
protected function update_sessions( $sessions ) {
if ( ! has_filter( 'attach_session_information' ) ) {
$sessions = wp_list_pluck( $sessions, 'expiration' );
}
if ( $sessions ) {
update_user_meta( $this->user_id, 'session_tokens', $sessions );
} else {
delete_user_meta( $this->user_id, 'session_tokens' );
}
}
/**
* Destroy all session tokens for a user, except a single session passed.
*
* @since 4.0.0
*
* @param $verifier Verifier of the session to keep.
*/
protected function destroy_other_sessions( $verifier ) {
$session = $this->get_session( $verifier );
$this->update_sessions( array( $verifier => $session ) );
}
/**
* Destroy all session tokens for a user.
*
* @since 4.0.0
*/
protected function destroy_all_sessions() {
$this->update_sessions( array() );
}
/**
* Destroy all session tokens for all users.
*
* @since 4.0.0
*/
public static function drop_sessions() {
delete_metadata( 'user', false, 'session_tokens', false, true );
}
}