Laravel memcached - same session across domains

Question

I have seen topics about this but all were about using memcached / database about it and my approach is similar.

Here is what I have:

• I have 2 domains lets say: dev.com and dev.eu
• I want to persist the session + shopping cart when I go between those 2 domains. If I add something to cart in dev.com I want to see it in dev.eu too.
• I am using Laravel 5.6 and I am using memcached for sessions.
• Just to be clear both domains are pointed to the same server.

Thanks for any ideas

Here are my config files

session.php

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Default Session Driver
    |--------------------------------------------------------------------------
    |
    | This option controls the default session "driver" that will be used on
    | requests. By default, we will use the lightweight native driver but
    | you may specify any of the other wonderful drivers provided here.
    |
    | Supported: "file", "cookie", "database", "apc",
    |            "memcached", "redis", "array"
    |
    */

    'driver' => 'memcached',

    /*
    |--------------------------------------------------------------------------
    | Session Lifetime
    |--------------------------------------------------------------------------
    |
    | Here you may specify the number of minutes that you wish the session
    | to be allowed to remain idle before it expires. If you want them
    | to immediately expire on the browser closing, set that option.
    |
    */

    'lifetime' => env('SESSION_LIFETIME', 120),

    'expire_on_close' => false,

    /*
    |--------------------------------------------------------------------------
    | Session Encryption
    |--------------------------------------------------------------------------
    |
    | This option allows you to easily specify that all of your session data
    | should be encrypted before it is stored. All encryption will be run
    | automatically by Laravel and you can use the Session like normal.
    |
    */

    'encrypt' => false,

    /*
    |--------------------------------------------------------------------------
    | Session File Location
    |--------------------------------------------------------------------------
    |
    | When using the native session driver, we need a location where session
    | files may be stored. A default has been set for you but a different
    | location may be specified. This is only needed for file sessions.
    |
    */

    'files' => storage_path('framework/sessions'),

    /*
    |--------------------------------------------------------------------------
    | Session Database Connection
    |--------------------------------------------------------------------------
    |
    | When using the "database" or "redis" session drivers, you may specify a
    | connection that should be used to manage these sessions. This should
    | correspond to a connection in your database configuration options.
    |
    */

    'connection' => null,

    /*
    |--------------------------------------------------------------------------
    | Session Database Table
    |--------------------------------------------------------------------------
    |
    | When using the "database" session driver, you may specify the table we
    | should use to manage the sessions. Of course, a sensible default is
    | provided for you; however, you are free to change this as needed.
    |
    */

    'table' => 'sessions',

    /*
    |--------------------------------------------------------------------------
    | Session Cache Store
    |--------------------------------------------------------------------------
    |
    | When using the "apc" or "memcached" session drivers, you may specify a
    | cache store that should be used for these sessions. This value must
    | correspond with one of the application's configured cache stores.
    |
    */

    'store' => 'memcached',

    /*
    |--------------------------------------------------------------------------
    | Session Sweeping Lottery
    |--------------------------------------------------------------------------
    |
    | Some session drivers must manually sweep their storage location to get
    | rid of old sessions from storage. Here are the chances that it will
    | happen on a given request. By default, the odds are 2 out of 100.
    |
    */

    'lottery' => [2, 100],

    /*
    |--------------------------------------------------------------------------
    | Session Cookie Name
    |--------------------------------------------------------------------------
    |
    | Here you may change the name of the cookie used to identify a session
    | instance by ID. The name specified here will get used every time a
    | new session cookie is created by the framework for every driver.
    |
    */

    'cookie' => "app",

    /*
    |--------------------------------------------------------------------------
    | Session Cookie Path
    |--------------------------------------------------------------------------
    |
    | The session cookie path determines the path for which the cookie will
    | be regarded as available. Typically, this will be the root path of
    | your application but you are free to change this when necessary.
    |
    */

    'path' => '/',

    /*
    |--------------------------------------------------------------------------
    | Session Cookie Domain
    |--------------------------------------------------------------------------
    |
    | Here you may change the domain of the cookie used to identify a session
    | in your application. This will determine which domains the cookie is
    | available to in your application. A sensible default has been set.
    |
    */

    'domain' => null,

    /*
    |--------------------------------------------------------------------------
    | HTTPS Only Cookies
    |--------------------------------------------------------------------------
    |
    | By setting this option to true, session cookies will only be sent back
    | to the server if the browser has a HTTPS connection. This will keep
    | the cookie from being sent to you if it can not be done securely.
    |
    */

    'secure' => env('SESSION_SECURE_COOKIE', false),

    /*
    |--------------------------------------------------------------------------
    | HTTP Access Only
    |--------------------------------------------------------------------------
    |
    | Setting this value to true will prevent JavaScript from accessing the
    | value of the cookie and the cookie will only be accessible through
    | the HTTP protocol. You are free to modify this option if needed.
    |
    */

    'http_only' => true,

    /*
    |--------------------------------------------------------------------------
    | Same-Site Cookies
    |--------------------------------------------------------------------------
    |
    | This option determines how your cookies behave when cross-site requests
    | take place, and can be used to mitigate CSRF attacks. By default, we
    | do not enable this as other CSRF protection services are in place.
    |
    | Supported: "lax", "strict"
    |
    */

    'same_site' => null,

];

cache.php

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Default Cache Store
    |--------------------------------------------------------------------------
    |
    | This option controls the default cache connection that gets used while
    | using this caching library. This connection is used when another is
    | not explicitly specified when executing a given caching function.
    |
    | Supported: "apc", "array", "database", "file", "memcached", "redis"
    |
    */

    'default' => "memcached",

    /*
    |--------------------------------------------------------------------------
    | Cache Stores
    |--------------------------------------------------------------------------
    |
    | Here you may define all of the cache "stores" for your application as
    | well as their drivers. You may even define multiple stores for the
    | same cache driver to group types of items stored in your caches.
    |
    */

    'stores' => [

        'apc' => [
            'driver' => 'apc',
        ],

        'array' => [
            'driver' => 'array',
        ],

        'database' => [
            'driver' => 'database',
            'table' => 'cache',
            'connection' => null,
        ],

        'file' => [
            'driver' => 'file',
            'path' => storage_path('framework/cache/data'),
        ],

        'memcached' => [
            'driver' => 'memcached',
            'persistent_id' => null,
            'sasl' => [],
            'options' => [
                // Memcached::OPT_CONNECT_TIMEOUT  => 2000,
            ],
            'servers' => [
                [
                    'host' => '127.0.0.1',
                    'port' => 11211,
                    'weight' => 100,
                ],
            ],
        ],

        'redis' => [
            'driver' => 'redis',
            'connection' => 'default',
        ],

    ],

    /*
    |--------------------------------------------------------------------------
    | Cache Key Prefix
    |--------------------------------------------------------------------------
    |
    | When utilizing a RAM based store such as APC or Memcached, there might
    | be other applications utilizing the same cache. So, we'll specify a
    | value to get prefixed to all our keys so we can avoid collisions.
    |
    */

    'prefix' => "app_cache"

];

Answer 1

Unfortunately, this is impossible. Laravel's session management identifies the client based on a cookie sent to that client. Such cookies cannot be shared between different domains of type dev.com and dev.eu, only between seperate subdomains. For a detailed example of what can be done with cookies and domain restrictions see for example the answers to How do browser cookie domains work?