Configurations are used to create new objects or initializing the existing ones. Configurations usually include a class name and a list of initial values. They may also include a list of event handlers and behaviors.
The following is an example of the database configuration −
<?php
$config = [
'class' => 'yii\db\Connection',
'dsn' => 'mysql:host = localhost;dbname = helloworld',
'username' => 'vladimir',
'password' => '12345',
'charset' => 'utf8',
];
$db = Yii::createObject($config);
?>
The Yii::createObject() method takes a configuration array and creates an object based on the class named in the configuration.
The format of a configuration −
[ //a fully qualified class name for the object being created 'class' => 'ClassName', //initial values for the named property 'propertyName' => 'propertyValue', //specifies what handlers should be attached to the object's events 'on eventName' => $eventHandler, //specifies what behaviors should be attached to the object 'as behaviorName' => $behaviorConfig, ]
The configuration file of a basic application template is one of the most complex −
<?php
$params = require(__DIR__ . '/params.php');
$config = [
'id' => 'basic',
'basePath' => dirname(__DIR__),
'bootstrap' => ['log'],
'components' => [
'request' => [
// !!! insert a secret key in the following (if it is empty) - this
//is required by cookie validation
'cookieValidationKey' => 'ymoaYrebZHa8gURuolioHGlK8fLXCKjO',
],
'cache' => [
'class' => 'yii\caching\FileCache',
],
'user' => [
'identityClass' => 'app\models\User',
'enableAutoLogin' => true,
],
'errorHandler' => [
'errorAction' => 'site/error',
],
'mailer' => [
'class' => 'yii\swiftmailer\Mailer',
// send all mails to a file by default. You have to set
// 'useFileTransport' to false and configure a transport
// for the mailer to send real emails.
'useFileTransport' => true,
],
'log' => [
'traceLevel' => YII_DEBUG ? 3 : 0,
'targets' => [
[
'class' => 'yii\log\FileTarget',
'levels' => ['error', 'warning'],
],
],
],
'urlManager' => [
//'showScriptName' => false,
//'enablePrettyUrl' => true,
//'enableStrictParsing' => true,
//'suffix' => '/'
],
'db' => require(__DIR__ . '/db.php'),
],
'modules' => [
'hello' => [
'class' => 'app\modules\hello\Hello',
],
],
'params' => $params,
];
if (YII_ENV_DEV) {
// configuration adjustments for 'dev' environment
$config['bootstrap'][] = 'debug';
$config['modules']['debug'] = [
'class' => 'yii\debug\Module',
];
$config['bootstrap'][] = 'gii';
$config['modules']['gii'] = [
'class' => 'yii\gii\Module',
];
}
return $config;
?>
In the above configuration file, we do not define the class name. This is because we have already defined it in the index.php file −
<?php
//defining global constans
defined('YII_DEBUG') or define('YII_DEBUG', true);
defined('YII_ENV') or define('YII_ENV', 'dev');
//register composer autoloader
require(__DIR__ . '/../vendor/autoload.php');
//include yii files
require(__DIR__ . '/../vendor/yiisoft/yii2/Yii.php');
//load application config
$config = require(__DIR__ . '/../config/web.php');
//create, config, and process request
(new yii\web\Application($config))->run();
?>
Many widgets also use configurations as shown in the following code.
<?php
NavBar::begin([
'brandLabel' => 'My Company',
'brandUrl' => Yii::$app->homeUrl,
'options' => [
'class' => 'navbar-inverse navbar-fixed-top',
],
]);
echo Nav::widget([
'options' => ['class' => 'navbar-nav navbar-right'],
'items' => [
['label' => 'Home', 'url' => ['/site/index']],
['label' => 'About', 'url' => ['/site/about']],
['label' => 'Contact', 'url' => ['/site/contact']],
Yii::$app->user->isGuest ?
['label' => 'Login', 'url' => ['/site/login']] :
[
'label' => 'Logout (' . Yii::$app->user->identity->username . ')',
'url' => ['/site/logout'],
'linkOptions' => ['data-method' => 'post']
],
],
]);
NavBar::end();
?>
When a configuration is too complex, a common practice is to create a PHP file, which returns an array. Take a look at the config/console.php configuration file −
<?php
Yii::setAlias('@tests', dirname(__DIR__) . '/tests');
$params = require(__DIR__ . '/params.php');
$db = require(__DIR__ . '/db.php');
return [
'id' => 'basic-console',
'basePath' => dirname(__DIR__),
'bootstrap' => ['log', 'gii'],
'controllerNamespace' => 'app\commands',
'modules' => [
'gii' => 'yii\gii\Module',
],
'components' => [
'cache' => [
'class' => 'yii\caching\FileCache',
],
'log' => [
'targets' => [
[
'class' => 'yii\log\FileTarget',
'levels' => ['error', 'warning'],
],
],
],
'db' => $db,
],
'params' => $params,
];
?>
The default configurations can be specified by calling the Yii::$container->set() method. It allows you to apply default configurations to all instances of the specified classes when they are called via the Yii::createObject() method.
For example, to customize the yii\widgets\LinkPager class, so that all link pagers will show at most three buttons, you can use the following code.
\Yii::$container->set('yii\widgets\LinkPager', [
'maxButtonCount' => 3,
]);