PHP code example of alejoluc / lazypdo

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

alejoluc / lazypdo example snippets

// autoloading, etc.
use alejoluc\LazyPDO\LazyPDO;

function expectsPDO(PDO $dependency) {
    //...
}

$lazypdo = new LazyPDO('mysql:host=localhost;dbname=db;charset=utf8', 'root', 'root');
expectsPDO($lazypdo); // Valid

// autoload, etc....
use alejoluc\LazyPDO\LazyPDO;

$pdo = new LazyPDO('mysql:host=localhost;dbname=db;charset=utf8', 'not_a_valid_user', 'pass');
$pdo->onConnectionError(function($ex) use ($app){
    $error = $ex->getMessage();
    $app->logError('PDO reported an error: ' . $error);
    $app->getDevelopers->angryEmail($error);
    $app->redirect('/database-maintenance');
    $app->shutdown();
});


$stmt = $pdo->prepare('SELECT ...'); // This will attempt a connection, the connection will fail, and the previously defined callback will handle the raised PDOException.

// joluc\LazyPDO\LazyPDO;

$pdo = new LazyPDO('mysql:host=localhost;dbname=information_schema;charset=utf8', 'root', 'root', [
    LazyPDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES       => false,
]);

// This will fail, there is no CHARACTER_SET table. To test the success scenario, change it to CHARACTER_SETS
$stmt = $pdo->prepare('SELECT * FROM CHARACTER_SET WHERE DEFAULT_COLLATE_NAME = ?');

if ($stmt === false) { // With this error mode, you must manually check errors
    $error = $pdo->errorInfo()[2];
    echo "Database error: $error";
    die();
}

$stmt->bindValue(1, 'utf8_general_ci');
$stmt->execute();

var_dump($stmt->fetchAll());

// joluc\LazyPDO\LazyPDO;

$pdo = new LazyPDO('mysql:host=localhost;dbname=information_schema;charset=utf8', 'root', 'root', [
    PDO::ATTR_ERRMODE                => LazyPDO::ERRMODE_EXCEPTION,
    LazyPDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES       => false,
]);

try {
    // This will fail, there is no CHARACTER_SET table. To test the success scenario, change it to CHARACTER_SETS
    $stmt = $pdo->prepare('SELECT * FROM CHARACTER_SET WHERE DEFAULT_COLLATE_NAME = ?');
    $stmt->bindValue(1, 'utf8_general_ci');
    $stmt->execute();

    var_dump($stmt->fetchAll());
} catch (PDOException $e) {
    echo "Database error: " . $e->getMessage();
    die();
}

// autoload, instantiate a pimple container into $c, store an hypothetical caching server connection into it, etc.
$c['db'] = function(){
    return new PDO('....');
};

function getUserData($userId, $db, $cacheConnection) {
    if ($cacheConnection->inCache('user:' . $userId)) {
        return $cacheConnection->getCached('user:' . $userId);
    } else {
        $stmt = $db->prepare('SELECT ...');
        // and so on and so on
    }
}

$data = getUserData('admin', $c['db'], $c['cache']); // You are accessing the 'db' key inside the Container, and a connection will try to be established because of that, although you can see in the getUserData() definition that no connection may be needed at all.

function getUserData($userId, $c) {
    if ($c['cache']->inCache('user:' . $userId)) {
        return $c['cache']->getCached('user:' . $userId);
    } else {
        $stmt = $c['db']->prepare('SELECT ...'); // PDO instantiation happens here, so it will not happen if the data is cached
        // and so on and so on
    }
}

getUserData('admin', $c);

// autoload, instantiate a pimple container into $c, store an hypothetical caching server connection into it, etc.
use alejoluc\LazyPDO\LazyPDO;
$c['db'] = function(){
    return new LazyPDO('....');
};

function getUserData($userId, $db, $cacheConnection) {
    if ($cacheConnection->inCache('user:' . $userId)) {
        return $cacheConnection->getCached('user:' . $userId);
    } else {
        $stmt = $db->prepare('SELECT ...'); // The connection will try to be established here, not on the getUserData() function call
    }
}

$data = getUserData('admin', $c['db'], $c['cache']); // No connection to the database will try to be established here because $c['db'] will return an instance of LazyPDO