Yii Error Handling Library

3.2.1 2024-03-07 07:46 UTC

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Last update: 2024-05-25 13:31:11 UTC



Yii Error Handler

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The package provides advanced error handling. The features are:

  • PSR-15 middleware for catching unhandled errors.
  • PSR-15 middleware for mapping certain exceptions to custom responses.
  • Production and debug modes.
  • Debug mode displays details, stacktrace, has dark and light themes and handy buttons to search for error without typing.
  • Takes PHP settings into account.
  • Handles out of memory errors, fatals, warnings, notices and exceptions.
  • Can use any PSR-3 compatible logger for error logging.
  • Detects response format based on mime type of the request.
  • Supports responding with HTML, plain text, JSON, XML and headers out of the box.
  • Has ability to implement your own error rendering for additional types.
  • Friendly exceptions support.


  • PHP 8.0 or higher.
  • DOM PHP extension.
  • JSON PHP extension.
  • mbstring PHP extension.


The package could be installed with Composer:

composer require yiisoft/error-handler

General usage

Creating an error handler:

use Yiisoft\ErrorHandler\ErrorHandler;
use Yiisoft\ErrorHandler\Renderer\HtmlRenderer;

 * @var \Psr\Log\LoggerInterface $logger

$errorHandler = new ErrorHandler($logger, new HtmlRenderer());

The error handler logs information about the error using any PSR-3 compatible logger. If for some reason you do not want to log error information, specify an instance of the \Psr\Log\NullLogger.

By default, the error handler is set to production mode and displays no detailed information. You can enable and disable debug mode as follows:

// Enable debug mode:

// Disable debug mode:

// Or define the environment dynamically:
$errorHandler->debug($_ENV['debug'] ?? false);

The error handler handles out-of-memory errors. To achieve it, memory is pre-allocated so that if a problem occurs with a lack of memory, the error handler can handle the error using this reserved memory. You can specify your own reserve size using the memoryReserveSize() method. If you set this value to 0, no memory will be reserved.

// Allocate 512KB. Defaults to 256KB.

The register() method registers the PHP error and exception handlers. To unregister these and restore the PHP error and exception handlers, use the unregister() method.

// Errors are being handled.
// Errors are not handled.

Rendering error data

The following renderers are available out of the box:

  • Yiisoft\ErrorHandler\Renderer\HeaderRenderer - Renders error into HTTP headers. It is used for HEAD requests.
  • Yiisoft\ErrorHandler\Renderer\HtmlRenderer - Renders error into HTML.
  • Yiisoft\ErrorHandler\Renderer\JsonRenderer - Renders error into JSON.
  • Yiisoft\ErrorHandler\Renderer\PlainTextRenderer - Renders error into plain text.
  • Yiisoft\ErrorHandler\Renderer\XmlRenderer - Renders error into XML.

If the existing renderers are not enough, you can create your own. To do this, you must implement the Yiisoft\ErrorHandler\ThrowableRendererInterface and specify it when creating an instance of the error handler.

use Yiisoft\ErrorHandler\ErrorHandler;

 * @var \Psr\Log\LoggerInterface $logger
 * @var \Yiisoft\ErrorHandler\ThrowableRendererInterface $renderer

$errorHandler = new ErrorHandler($logger, $renderer);

For more information about creating your own renders and examples of rendering error data, see here.

Using middleware for catching unhandled errors

Yiisoft\ErrorHandler\Middleware\ErrorCatcher is a PSR-15 middleware that catches exceptions that appear during middleware stack execution and passes them to the handler.

use Yiisoft\ErrorHandler\Middleware\ErrorCatcher;

 * @var \Psr\Container\ContainerInterface $container
 * @var \Psr\Http\Message\ResponseFactoryInterface $responseFactory
 * @var \Psr\Http\Message\ServerRequestInterface $request
 * @var \Psr\Http\Server\RequestHandlerInterface $handler
 * @var \Yiisoft\ErrorHandler\ErrorHandler $errorHandler
 * @var \Yiisoft\ErrorHandler\ThrowableRendererInterface $renderer

$errorCatcher = new ErrorCatcher($responseFactory, $errorHandler, $container);

// In any case, it will return an instance of the `Psr\Http\Message\ResponseInterface`.
// Either the expected response, or a response with error information.
$response = $errorCatcher->process($request, $handler);

The error catcher chooses how to render an exception based on accept HTTP header. If it is text/html or any unknown content type, it will use the error or exception HTML template to display errors. For other mime types, the error handler will choose different renderer that is registered within the error catcher. By default, JSON, XML and plain text are supported. You can change this behavior as follows:

// Returns a new instance without renderers by the specified content types.
$errorCatcher = $errorCatcher->withoutRenderers('application/xml', 'text/xml');

// Returns a new instance with the specified content type and renderer class.
$errorCatcher = $errorCatcher->withRenderer('my/format', new MyRenderer());

// Returns a new instance with the specified force content type to respond with regardless of request.
$errorCatcher = $errorCatcher->forceContentType('application/json');

Using middleware for mapping certain exceptions to custom responses

Yiisoft\ErrorHandler\Middleware\ExceptionResponder is a PSR-15 middleware that maps certain exceptions to custom responses.

use Yiisoft\ErrorHandler\Middleware\ExceptionResponder;

 * @var \Psr\Http\Message\ResponseFactoryInterface $responseFactory
 * @var \Psr\Http\Message\ServerRequestInterface $request
 * @var \Psr\Http\Server\RequestHandlerInterface $handler
 * @var \Yiisoft\Injector\Injector $injector
$exceptionMap = [
    // Status code with which the response will be created by the factory.
    MyNotFoundException::class => 404,
    // PHP callable that must return a `Psr\Http\Message\ResponseInterface`.
    MyHttpException::class => static fn (MyHttpException $exception) => new MyResponse($exception),
    // ...

$exceptionResponder = new ExceptionResponder($exceptionMap, $responseFactory, $injector);

// Returns the expected response, or the response associated with the thrown exception,
// or throws an exception if it does not present in the exception map.
$response = $exceptionResponder->process($request, $handler);

In the application middleware stack Yiisoft\ErrorHandler\Middleware\ExceptionResponder must be placed before Yiisoft\ErrorHandler\Middleware\ErrorCatcher.


  • When ErrorCatcher catches an error it dispatches \Yiisoft\ErrorHandler\Event\ApplicationError event.

Friendly Exceptions

HtmlRenderer supports friendly exceptions.

Code blocks in solution markdown support language syntax highlight:

Language Aliases
Bash bash, sh, zsh
CSS css
HTML, XML xml, html, xhtml, rss, atom, xjb, xsd, xsl, plist, svg
JavaScript javascript, js, jsx
JSON json
PHP php
Plaintext plaintext, txt, text
SQL sql

For example:

    <p>This text is normal.</p>
    <p><b>This text is bold.</b></p>


If you need help or have a question, the Yii Forum is a good place for that. You may also check out other Yii Community Resources.


The Yii Error Handler is free software. It is released under the terms of the BSD License. Please see LICENSE for more information.

Maintained by Yii Software.


The Yii Error Handler use code of Highlight.js by Ivan Sagalaev and other contributors.

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