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<?php
/** SessionHandlerInterface
*
* as of php's documentation (check manual)
* https://www.php.net/manual/en/class.sessionhandlerinterface.php
*/
interface SessionHandlerInterface
{
/* Methods
*--------------------------------------------------------------------------
*/
public function open(string $path, string $name) : bool;
public function close() : bool;
public function read(string $id) : string|false;
public function write(string $id, string $data) : bool;
public function destroy(string $id) : bool;
public function gc(int $max_lifetime) : int|false;
}
/** TODO: (thoughts)
* ... for a brand-new session implementation
*
* In most cases, the session data does not require persistence.
* The session information could be cached to improve performance
*
* So (in theory) we could create a two-dimension session mechanism
*
* + a fast dimension
* : could be file-based (using local FS [php's default?] or redis/memcached)
*
* + a shared dimension
* : implemented in a shared database
*
* Posible algo:
* ... (check later on this comment-block: session life-cycle )
*
* open :
* close : on both
* read : check Local; if not exist check database; set session_id($id)
* write : on both
* destroy : on both
* gc : on server
*
* when regenerating session_id, keep database informed about the new session_id
* when closing, keep database informed about the session end-of-life.
*
* a session timeout on the local leg will trigger a confirm-session-from-db
*
* garbage collector on the db should remove expired sessions of some X seconds
* and earier (X needs to be determined by practice/expirience/tries)
*
* (+) in order to keep tracking of the session between multiple servers through
* the (shared) database, a unique secret-between-the-servers id can be used
*
* so...
*
* #1
* -> someone visits website through server A
* -> server A creates a new session-id for the visitor and a shared-session-id
* -> saves both into database
*
* later...
*
* #2
* -> the same device is connected (via loadbalancer) into server B
* -> server B don't have the session-id (send by the client) but gets it from db
* (is session-id do not exist on the db, then this is a new session)
*
* = now both server A and B have the same session-id localy
*
* later...
*
* #3
* -> some server (let's say B) regenerates the visitors session-id
* -> if later the visitor falls into server A, the A will retrieve the new
* session id through the #2 scenario
*
* this way
* + any server can update/regenerate the visitor's session-id
* + the visitor can be served from both servers randomly
* + all session variables exist on the database (always)
* + all session variables exist on all servers synced-on-demand
*
*
* stucture of session:
* ---
* - shared-session-id: (secret + persistent); exposed between servers **primary
* - session-id: (may change/regenerate/update); exposed to the client **indexed
* - data: serialized array
* - creation_timestamp:
* - last_touched_timestamp:
* - expiration_timestamp: should point to the future or session has expired
* - csrf_token:
* - JWT_token
* - AES-key (this way private data can be kept in browser)
*
*
* what will kept on browser/client (via cookie)
* ---
* - session-name => session-id
* - user info => AES_ectypted(serialized[t=>csfr_token, u=> user_id, s=>SIGNATURE])
*
*
* Writable file-system shall change
* (local writable file-system tree)
* ---
* /html/storage
* |
* |-- cache : query-caches
* |
* `-- session : FS\sessions
* |
* `-- indexes : share-session-id indexes
*
*
*
* NOTE: Session life-cycle
*
* session_start() * firsts time
* ---
* ::open(path,PHPSESSID) -> (session_id not exist) -> false
* ::create_sid -> '123def'
* ::read('123def') ?-or/and- ::close()
*
*
* session_start() * next times
* ---
* ::open(path, PHPSESSID) -> (session_id exist) -> true
* ::read('123def') -> return data -> will fill $_SESSION[*]
*
*
* $_SESSION['foo'] = 'bar';
* ---
* ::write('123def', 'foo|s:3:"bar";') -> ['foo' => "bar"]
* ::close()
*
*
* session_regenerate_id();
* ---
* ::create_sid() -> def123
*
*
* session_reset()
* ---
* ::open()
* ::read('def123')
*
*
* session_write_close()
* ---
* ::write('123def', 'foo|s:3:"bar";')
* ::close()
*
*
* session_destroy()
* ---
* ::destroy('def123')
* ::close()
*
*/
|
