Configuration / Advanced Configuration / Sessions

Note: You are currently reading the documentation for Bolt 3.7. Looking for the documentation for Bolt 5.2 instead?

By default, Bolt's sessions are managed behind the scenes for you by a configurable abstraction layer.

Configuration options are selected based on an order of precedence from varying locations, and merges options together.

Precedence is as follows:

• Options from $app['session.options']
• Options from php.ini, if enabled with $app['session.options.import_from_ini'] (enabled by default)
• Fallback default options hard-coded in Bolt's SessionServiceProvider

These defaults are limited to those that are useful, and secure.

Note: Under most circumstances you should not need to adjust these settings.

Setting options¶

Changing session settings for a Bolt site can be done either by editing the site's config.yml file, or via dependency injection.

in your config.yml, settings are done adding the required parameter key and value, to the session key, i.e.:

session:
    key: value

Setting via dependency injection is done by calling $app->share($app->extend()) on the 'session.options' container value, i.e.:

$app['session.options'] = $app->share($app->extend(
    'session.options',
    function ($options) {
        // Use the $options parameter as a key/value hash map.
        // $options['key'] = 'value';

        return $options;
    }
));

Browser cookies¶

By default, Bolt will inherit the settings cookies_lifetime, cookies_domain, and enforce_ssl (for cookie_secure) should no override options be set, as per the order of precedence explained in the introduction.

However, there are several override settings available, should you need more fine-grained control.

Life time¶

Time in seconds, that a cookie will be valid for. Setting this value to 0 means "until the browser is closed".

In .php.ini this setting is session.cookie_lifetime.

Base URI path¶

Specifies URI path to set in the session cookie.

In .php.ini this setting is session.cookie_path.

Override domain name¶

Specifies the domain to set in the session cookie. Default is null, meaning the host name of the server which generated the cookie.

In .php.ini this setting is session.cookie_domain.

Enforce HTTPS requests¶

Setting this to true will enforce a HTTPS connection requirement to set, and use, the session cookie.

In .php.ini this setting is session.cookie_secure.

Restricting request to the HTTP protocol¶

Marks the cookie as accessible only through the HTTP protocol, blocking access to requests by things such as JavaScript.

This setting can effectively help to reduce identity theft through XSS attacks, although browser support may vary.

Setting in your config.yml:

In .php.ini this setting is session.cookie_httponly.

Session ID generation¶

Session IDs are randomly generated to uniquely identify a user's session. Bolt internally handles this generation in a fashion close to how PHP 7.1+ now does to better ensure the uniqueness of the generated ID.

By default, both PHP & Bolt use an ID length of 32, which should provide only a small chance of collisions, or predictability, of the generated ID.

On hosts with a consistent amount of available CPU resources, and a focus on security, you should consider a number of 48 or greater. However, this will increase the server load, and amount of time taken to generate session IDs.

An example of generating 1,000 session IDs on PHP 7.0 and an Intel i5-5200:

Maximum value supported is 256.

In PHP 7.1+ the .php.ini this setting is session.sid_length.

Session storage handler¶

Session storage handling, by default, is our filesystem layer. However, we also support Redis & Memcached for more advanced use-cases.

Setting in your config.yml:

In .php.ini this setting is session.save_handler.

Note: Some web hosting providers may implement alternative session handling that is not compatible with Bolt's.
Should you encounter exceptions from SessionServiceProvider indicating problems with PHP's system save path, set save_handler: filesystem, and the save_path option shown below.

Using the Redis handler¶

When using Redis as the handler, the following options are also under the connection subkey, of the session options:

If the native \Redis library is available, it will be used as the handler for Redis, if not available, it will instead check for the PHP implementation of the native library, \Predis\Client and use that.

Example configuration:

session:
    save_handler: redis
    connection:
        host: redis.example.com
        persistent: true
        prefix: myprefix.

Using the Memcached handler¶

When using Memcached as the handler, the following options are also under the connection subkey, of the session options:

Example configuration:

session:
    save_handler: memcached
    connection:
        host: memcached.example.com
        weight: 0
        expiretime: 86400
        prefix: myprefix.

Saved session file path¶

Session data is cached in between requests. Bolt puts these files in a hidden directory of the cache, and is not cleared by the normal cache clearing functionality in Bolt.

Instead, it uses garbage collection to manage deletion of expired sessions. See the section below on garbage collection for details on configuration.

Note: Manually deleting session data on a live server is never advised. Should this ever be required on a live server, ensure all users are logged off, and place the site into maintenance mode first.

In .php.ini this setting is session.save_path.

Using the Filesystem handler¶

When using the default filesystem handler, the save_path parameter needs to be in the form of {mount point}://{path}.

See the Overview of Bolt's Filesystem page for details on the mount points available in Bolt.

Warning: If you set this to a world-readable directory, such as /tmp, other users on the server may be able to hijack sessions, or extract potentially sensitive data.

Using the Redis handler¶

When using Redis as the handler, save_path should be defined in the format tcp://IPADDRESS:PORT, with a default of tcp://127.0.0.1:6379.

Using the Memcached handler¶

When using Memcached as the handler, save_path should be defined in the format IPADDRESS:PORT, with a default of 127.0.0.1:11211.

Garbage collection¶

Session garbage collection is the removal of sessions older than the configured maximum life time.

The need to perform garbage collection is determined based on a random probability calculation during the initialisation of each session.

Maximum life time¶

The maximum life time setting specifies the number of seconds after which session data will be seen as 'garbage' and potentially cleaned up.

In .php.ini this setting is session.gc_maxlifetime.

Probability & divisor¶

The setting gc_divisor coupled with gc_probability define the probability that the garbage collection (GC) process is performed.

In Bolt's session storage handler, the probability is calculated by generating a random number between 0 and gc_divisor. If the value of gc_probability is greater than the random number, garbage collection will be performed, and session files older than the maximum configured life time are removed.

Note: To disable garbage collection, set gc_probability to -1.

In .php.ini these settings are:

• session.gc_probability
• session.gc_divisor