README

SessionWare

A PSR7 session management middleware.

Automatic control of session timeout.

Generates a 80 character long session_id using random_bytes, a truly cryptographically secure pseudo-random generator, instead of session.hash_function hash algorithm.

Important considerations

Be aware that this middleware needs some session ini settings to be set to specific values:

session.use_trans_sid to false session.use_cookies to true session.use_only_cookies to true session.use_strict_mode to false session.cache_limiter to '' (empty string)

This values will prevent session headers to be automatically sent to user. It's the developer's responsibility to include corresponding cache headers in response object, which should be the case in the first place instead of relying on PHP environment settings.

You can use juliangut/cacheware which will automatically set the corrent session ini settings and add the corresponding cache headers to response object.

By using session_regenerate_id() during execution cryptographically secure session ID will be replaced by default PHP session.hash_function generated ID (not really secure). To prevent this from happening use \Jgut\Middleware\Session helper method regenerateSessionId() instead:

\Jgut\Middleware\Session::regenerateSessionId();

Installation

Composer

composer require juliangut/sessionware

Usage

require 'vendor/autoload.php';

use \Jgut\Middleware\SessionWare

$configuration = [
  'name' => 'myProjectSessionName',
  'lifetime' => 1800, // 30 minutes
];

$sessionMiddleware = new SessionWare($configuration);

// Get $request and $response from PSR7 implementation
$request = new Request();
$response = new Response();

$response = $sessionMiddleware($request, $response, function() { });

// Session is started, populated with default parameters and response has session cookie header

Integrated on a Middleware workflow:

require 'vendor/autoload.php';

use \Jgut\Middleware\SessionWare

$configuration = [
  'name' => 'myProjectSessionName',
  'lifetime' => SessionWare::SESSION_LIFETIME_NORMAL, // 15 minutes
];
$defaultSessionParams = [
  'default_timezone' => 'UTC',
]

$app = new \YourMiddlewareAwareApplication();
$app->addMiddleware(new SessionWare($configuration, $defaultParameters));
$app->run();

Session helper

There is an extra Session helper to abstract access to the $_SESSION variable. This is usefull for example when NOT accessing global variables is important for you (such as when using PHP_MD to statically analise your code)

In order to benefit from SessionWare cryptographically secure generated session id DO use

$session = new \Jgut\Middleware\Session;
$session->regenerate();

// Or can be called statically
\Jgut\Middleware\Session::regenerateSessionId()

Config

$sessionMiddleware = new SessionWare([
  'timeoutKey' => '__SESSIONWARE_TIMEOUT_TIMESTAMP__'
  'name' => 'SessionWareSession',
  'savePath' => '/tmp/SessionWareSession',
  'lifetime' => SessionWare::SESSION_LIFETIME_NORMAL,
  'domain' => 'http://example.com',
  'path' => '/',
  'secure' => false,
  'httponly' => true,
]);

Default values mimic those provided by default PHP installation so the middleware can be used as a direct drop-in with automatic session timeout control

timeoutKey

Parameter stored in session array to control session validity according to lifetime parameter. Defaults to

\Jgut\Middleware\SessionWare::SESSION_TIMEOUT_KEY_DEFAULT = '__SESSIONWARE_TIMEOUT_TIMESTAMP__';

It is advised not to change this value unless it conflicts with one of your own session keys (which is unlikely if not directly impossible)

name

Assigns session name, default PHP PHPSESSID session name will be used if none provided.

Review Important note below.

savePath

This configuration is used only if default 'files' session save handler is selected in session.save_handler.

Assigns the path to store session files. If none provided sys_get_temp_dir(), session_save_path() and session 'name' will be used to compose a unique path.

Review Important note below.

lifetime

Number of seconds for the session to be considered valid. uses session.gc_maxlifetime and session.cookie_lifetime to discover PHP configured session lifetime if none provided. Finally it defaults to SessionWare::SESSION_LIFETIME_DEFAULT (24 minutes) if previous values are not available or their value is zero.

There are six session lifetime constants available for convenience:

• SESSION_LIFETIME_FLASH = 5 minutes
• SESSION_LIFETIME_SHORT = 10 minutes
• SESSION_LIFETIME_NORMAL = 15 minutes
• SESSION_LIFETIME_DEFAULT = 24 minutes
• SESSION_LIFETIME_EXTENDED = 1 hour
• SESSION_LIFETIME_INFINITE = PHP_INT_MAX, around 1145 years on x86_64 architecture

path, domain, secure and httponly

Shortcuts to session.cookie_path, session.cookie_domain, session.cookie_secure and session.cookie_httponly. If not provided configured cookie params will be used, so can be set using session_set_cookie_params() before middleware run.

Events

You can listen to timeout events to perform actions accordingly. There are currently two events

• pre.session_timeout triggered right before session is wiped when session timeout is reached
• post.session_timeout triggered right after session has been restarted due to session timeout

Events provide sessionId as parameter:

$sessionware = new SessionWare($configuration);
$sessionware->addListener('pre.session_timeout', function($sessionId) {
    echo sprintf('session "%s" timed out', $sessionId);
})
$sessionware->addListener('post.session_timeout', function($sessionId) {
    echo sprintf('new session "%s" created', $sessionId);
})

Important note

Using default 'files' session save handler

If you define a session 'lifetime' you MUST set a session 'savePath' or a session 'name' (different to PHPSESSID). This is to separate session files from other PHP scripts session files, for the garbage collector to handle expired files removal correctly.

Be aware that if this condition is not met starting a session might remove session files from other script/application as they are all located in the same directory and there is no way for the garbage collector to tell which script/application they belong to.

Using custom session save handler

Distinguishing between different script/application session files shouldn't be a problem in this case. But be carefull not to send cookie headers (setcookie) directly to the client but to include them in the response object instead.

Register your custom session save handler before running this middleware to prevent savePath to be created.

Contributing

Found a bug or have a feature request? Please open a new issue. Have a look at existing issues before.

See file CONTRIBUTING.md

License

See file LICENSE included with the source code for a copy of the license terms.