Yii – Error Handling
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Yii includes a built-in error handler. The Yii error handler does the following −
- Converts all non-fatal PHP errors into catchable exceptions.
- Displays all errors and exceptions with a detailed call stack.
- Supports different error formats.
- Supports using a controller action to display errors.
To disable the error handler, you should define the YII_ENABLE_ERROR_HANDLER constant to be false in the entry script. The error handler is registered as an application component.
Step 1 − You can configure it in the following way.
return [ ''components'' => [ ''errorHandler'' => [ ''maxSourceLines'' => 10, ], ], ];
The above configuration sets the number of source code lines to be displayed to 10. The error handler converts all non-fatal PHP errors into catchable exceptions.
Step 2 − Add a new function called actionShowError() to the SiteController.
public function actionShowError() { try { 5/0; } catch (ErrorException $e) { Yii::warning("Ooops...division by zero."); } // execution continues... }
Step 3 − Go to the URL http://localhost:8080/index.php?r=site/show-error. You will see a warning message.
If you want to show the user that his request is invalid, you may throw the yiiwebNotFoundHttpException.
Step 4 − Modify the actionShowError() function.
public function actionShowError() { throw new NotFoundHttpException("Something unexpected happened"); }
Step 5 − Type the address http://localhost:8080/index.php?r=site/show-error in the address bar. You will see the following HTTP error.
When the YII_DEBUG constant is true, the error handler will display errors with a detailed call stack. When the constant is false, only the error message will be displayed. By default, the error handler shows errors using these views −
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@yii/views/errorHandler/exception.php − the view file is used when errors should be displayed with call stack information.
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@yii/views/errorHandler/error.php − the view file is used when errors should be displayed without call stack information.
You can use dedicated error actions to customize the error display.
Step 6 − Modify the errorHandler application component in the config/web.php file.
<?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'' => ''yiicachingFileCache'', ], ''user'' => [ ''identityClass'' => ''appmodelsUser'', ''enableAutoLogin'' => true, ], ''errorHandler'' => [ ''errorAction'' => ''site/error'', ], //other components... ''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; ?>
The above configuration defines that when an error needs to be displayed without the call stack, the site/error action will be executed.
Step 7 − Modify the actions() method of the SiteController.
public function actions() { return [ ''error'' => [ ''class'' => ''yiiwebErrorAction'', ], ]; }
The above code defines, that when an error occurs, the error view will be rendered.
Step 8 − Create a file called error.php under the views/site directory.
<?php /* @var $this yiiwebView */ /* @var $name string */ /* @var $message string */ /* @var $exception Exception */ use yiihelpersHtml; $this->title = $name; ?> <div class = "site-error"> <h2>customized error</h2> <h1><?= Html::encode($this->title) ?></h1> <div class = "alert alert-danger"> <?= nl2br(Html::encode($message)) ?> </div> <p> The above error occurred while the Web server was processing your request. </p> <p> Please contact us if you think this is a server error. Thank you. </p> </div>
Step 9 − Go to the address http://localhost:8080/index.php?r=site/show-error, you will see the customized error view.
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