Nov 21, 2019

Level 4

PHP Pracitioner episode 16, making a router

Hello, i have been trying to grasp myself around this episode and i think i finally figured everything out, but not quite. In the lecture Jeffrey has a config file that looks like the code below

$app = [];

$app['config'] = require 'config.php';

require 'core/Router.php'; require 'core/Request.php'; require 'core/database/QueryBuilder.php'; require 'core/database/Connection.php'; $config = require 'config.php';

$app['database'] = new QueryBuilder( Connection::make($app['config']['database']) );

Can someone explain this last piece of code, having a hard time grasping why do we pass ['config']['database'].

Code for QueryBuilder:

class QueryBuilder {

protected $pdo;

public function __construct($pdo) {

    $this->pdo = $pdo;
    
}

public function selectAll($table) {

    $statement = $this->pdo->prepare("select * from {$table}");

    $statement->execute();

    return $statement->fetchAll(PDO::FETCH_CLASS);

}

}

Code for Connection class:

class Connection {

public static function make($config) {

    try {

        return new PDO(
          
            $config['connection'] . ';dbname=' . $config['name'],
            $config['username'],
            $config['password'],
            $config['options']

        );

    } catch (\Throwable $th) {
        
        die($th->getMessage());

    }

}

}

Thanks in advance

bugsysha

6 years ago

Level 61

Can you reformat the first part since it's hard to read?

Markk

6 years ago

Level 4

Sorry, but the "code" feature doesn't work properly i guess.. Hope this makes it clearer

$app = [];

$app['config'] = require 'config.php';

require 'core/Router.php'; require 'core/Request.php'; require 'core/database/QueryBuilder.php'; require 'core/database/Connection.php'; $config = require 'config.php';

$app['database'] = new QueryBuilder(

Connection::make($app['config']['database'])

);

Edit: I refactor it, but when i post it, it get's messed up...

manelgavalda

6 years ago

Level 50

$databaseConfig = $app['config']['database']);

The Connection class is the responsable of connecting to the database, so you are passing the configuration of your database that is actually inside your config file so it knows how to make the connection.

$connection = Connection::make($databaseConfig);

Then the QueryBuilder is the class responsable to make the queries to the connected database, so it expects the connection ($pdo).

$app['database'] = new QueryBuilder($connection);

Then you save your QueryBuilder class inside the $app['database'] variable so you can then use the methods to query the database inside the QueryBuilder class like this.

$app['database']->selectAll('tableName')

1 like

ismaile

6 years ago

Best Answer

Level 30

Ok, let's take this steps by steps, you are passing to Connection::make the parameter $app['config']['database']. Let's look at the static function make, it accepts a $config variable and this variable is an associative array. Why is it an associative array ? Because, we have statements like $config['connection']. So$config must be equal to something like this:

array(
    'connection' => 'mysql',
    'name' => 'project',
    'username' => 'ausername',
    'password' => 'apassword',
    'options' => []
)

So, we know what make expects. What about the parameter passed: $app['config']['database']. We see in the code that:

$app['config'] = require 'config.php';

So, $app['config'] is equal to whatever is returned from the config file. Since once again in the parameter call, we are saying not only $app['config'] but $app['config']['database'], this means we are trying to access a database key in $app['config'], this means that config.php returns an associative array like this:

return array(
    'database' => array()
);

Then if we group the pieces together, the first piece of code shows what Connection::make expects as a parameter, this second one above shows what must be in config.php. So to give to Connection::make the proper information through $app['config']['database'], the database key in config.php must have all that information, so here is our config.php:

return array(
    'database' => array(
        'connection' => 'mysql',
        'name' => 'project',
        'username' => 'ausername',
        'password' => 'apassword',
        'options' => []
    )
);

1 like

Markk

6 years ago

Level 4

Wow, thanks for the explanation, now getting the whole picture.

1 like

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