Fatfree php (v3.6.5) dependency injection CONTAINER - dependency-injection

Question

Does anybody have a simple example of usage?
https://fatfreeframework.com/3.6/quick-reference#CONTAINER page
seem to me not really explanatory, but generally i need to figure a nice way to auto-inject $db_connection object just when/where needed, e.g.
In class's beforeRoute() method for smooth route resolving

Answer 1

When porting selfoss to use DI, I chose Dice as suggested in the docs you linked. I set up the container to use only a single shared instance of the DB class and pass it the connection string:
$f3 = Base::instance();
$dice = new Dice\Dice;
$host = $f3->get('db_host');
$database = $f3->get('db_database');
$dsn = "pgsql:host=$host; dbname=$database";
$dbParams = [
$dsn,
$f3->get('db_username'),
$f3->get('db_password')
];
$dice->addRule(DB\SQL::class, [
'constructParams' => $dbParams,
'shared' => true,
]);
$f3->set('CONTAINER', function($class) use ($dice) {
return $dice->create($class);
});
Then F3 will use the Dice container to create classes so controllers and any of their dependencies will be passed the instantiated dependencies in the constructor:
namespace daos;
class Items {
private DB\SQL $db;
public function __construct(DB\SQL $db) {
$this->db = $db;
}
public function fetchAll() {
$entries = $this->db->exec(…);
…
}
}
See the selfoss source code for a full example of how to configure the dependency container.

Answer 2

So, i've opted for singleton:
// Database class
class DB
{
private static $_instance = null;
private $dbconn = null;
// config files should better be located in more secure dir
const DB_HOST = '127.0.0.1';
const DB_NAME = 'my_db_name';
const DB_USER = 'my_db__user';
const DB_PASS = 'my_db_passw';
const CHARSET = 'utf8';
const DB_PREFIX = '';
///////////////////////////////////
private function __construct () {
$this->dbconn=new DB\SQL(
'mysql:host='.self::DB_HOST.';port='.self::DB_PORT.';dbname='.self::DB_NAME,
self::DB_USER,
self::DB_PASSW,
$options = array(
\PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
\PDO::ATTR_PERSISTENT => FALSE)
);
}
////////////////////////////////////
public static function getInstance() {
if (!self::$_instance) {
self::$_instance = new DB();
}
return self::$_instance;
}
//////////////////////////////////
public function connect() {
if ($this->dbconn) {
echo 'Hooray - 1st stage connected!';
return $this->dbconn;
}
else echo '<br>Sad enough, no connection :(((';
}
///////////// ///////////////// ////////////////////
private function __clone() { }
private function __wakeup() { }
}

Answer 3

Sorry for dummyness, i've just discovered for myself built in \Prefab class (to be extended for singletons), so the above DB connection i'd rather do LIKE%:
class DB extends \Prefab {
private $dbconn;
// ..then just do connection thing
public function connect() {
//////
}
}