Yii - Configurations

Configurations are used to create new objects or initiapzing the existing ones. Configurations usually include a class name and a pst of initial values. They may also include a pst of event handlers and behaviors.

The following is an example of the database configuration −

<?php
   $config = [
       class  =>  yiidbConnection ,
       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 quapfied 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 apppcation 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 vapdation
             cookieVapdationKey  =>  ymoaYrebZHa8gURuopoHGlK8fLXCKjO ,
         ],
          cache  => [
             class  =>  yiicachingFileCache ,
         ],
          user  => [
             identityClass  =>  appmodelsUser ,
             enableAutoLogin  => true,
         ],
          errorHandler  => [
             errorAction  =>  site/error ,
         ],
          mailer  => [
             class  =>  yiiswiftmailerMailer ,
            // 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  =>  yiilogFileTarget ,
                   levels  => [ error ,  warning ],
               ],
            ],
         ],
          urlManager  => [
            // showScriptName  => false,
            // enablePrettyUrl  => true,
            // enableStrictParsing  => true,
            // suffix  =>  / 
         ],
          db  => require(__DIR__ .  /db.php ),
      ],
       modules  => [
          hello  => [
             class  =>  appmoduleshelloHello ,
         ],
      ],
       params  => $params,
   ];
   if (YII_ENV_DEV) {
      // configuration adjustments for  dev  environment
      $config[ bootstrap ][] =  debug ;
      $config[ modules ][ debug ] = [
          class  =>  yiidebugModule ,
      ];
      $config[ bootstrap ][] =  gii ;
      $config[ modules ][ gii ] = [
          class  =>  yiigiiModule ,
      ];
   }
   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 apppcation config
   $config = require(__DIR__ .  /../config/web.php );
   //create, config, and process request
   (new yiiwebApppcation($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 ],
             pnkOptions  => [ 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::setApas( @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  =>  appcommands ,
       modules  => [
          gii  =>  yiigiiModule ,
      ],
       components  => [
          cache  => [
             class  =>  yiicachingFileCache ,
         ],
          log  => [
             targets  => [
               [
                   class  =>  yiilogFileTarget ,
                   levels  => [ error ,  warning ],
               ],
            ],
         ],
          db  => $db,
      ],
       params  => $params,
   ];
?>

The default configurations can be specified by calpng 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 yiiwidgetsLinkPager class, so that all pnk pagers will show at most three buttons, you can use the following code.

Yii::$container->set( yiiwidgetsLinkPager , [
    maxButtonCount  => 3,
]);